Category: CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development

Category: CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development

CSIR NET Life Science Previous Year Questions and Solutions on Basic Concepts of Development

If you are preparing for CSIR NET Life Science, a strong foundation in the Basic Concepts of Development is essential. These concepts form the backbone of Developmental Biology and are frequently tested in the exam. Practicing previous year questions along with their solutions can help aspirants understand exam patterns, focus on important topics, and improve problem-solving skills.

This article provides a comprehensive guide on CSIR NET Life Science previous year questions and solutions related to Basic Concepts of Development, along with preparation strategies and resources.

What are the Basic Concepts of Development?

Basic Concepts of Development include the fundamental principles that govern how organisms grow, differentiate, and develop from a single cell to a fully functional organism. In the CSIR NET syllabus, the key areas include:

  • Cell differentiation and fate determination – How cells become specialized

  • Induction and competence – Role of signals in guiding development

  • Morphogen gradients – Spatial regulation of tissue patterning

  • Stem cells and regeneration – Understanding totipotency, pluripotency, and multipotency

  • Gene regulation in development – Role of transcription factors and signaling pathways

  • Developmental plasticity – How environment and signals influence development

Mastery of these concepts is crucial because CSIR NET questions often test both conceptual understanding and application.

Importance of Practicing Previous Year Questions

Solving previous year questions (PYQs) is a key strategy for CSIR NET Life Science preparation. Here’s why:

  1. Exam Familiarity: Understand the type of questions asked on basic developmental concepts.

  2. Identify High-Yield Topics: Frequent questions indicate important areas.

  3. Time Management: Learn to solve questions accurately within a limited time.

  4. Self-Assessment: Evaluate your understanding and identify weak areas.

Sample Previous Year Questions on Basic Concepts of Development

Here are some examples of CSIR NET Life Science previous year questions on basic concepts of development:

  1. Question: Define induction in developmental biology.
    Solution: Induction is a process in which one group of cells (the inducer) influences the fate or differentiation of another group of cells (the responder) through chemical signals.

  2. Question: What is the role of morphogens in embryonic development?
    Solution: Morphogens are signaling molecules that form concentration gradients and determine cell fate based on their position. Example: Bicoid protein in Drosophila anterior-posterior patterning.

  3. Question: Explain the difference between totipotent, pluripotent, and multipotent cells.
    Solution:

    • Totipotent: Can form all cell types, including extra-embryonic tissues (e.g., zygote).

    • Pluripotent: Can form all embryonic cell types but not extra-embryonic tissues (e.g., embryonic stem cells).

    • Multipotent: Can form multiple related cell types (e.g., hematopoietic stem cells).

  4. Question: What is competence in developmental biology?
    Solution: Competence refers to the ability of a group of cells to respond to inductive signals. Only competent cells can differentiate in response to an inducer.

  5. Question: Name one gene that regulates anterior-posterior axis formation in vertebrates.
    Solution: Hox genes are key regulators of anterior-posterior axis formation in vertebrate development.

How to Prepare Basic Concepts of Development for CSIR NET

  1. Understand Core Concepts: Focus on induction, competence, morphogens, cell fate, and stem cells.

  2. Use Diagrams: Draw diagrams for processes like morphogen gradients, induction, and cell differentiation. Visual learning helps in MCQs and diagram-based questions.

  3. Solve MCQs and PYQs: Practice previous year questions to reinforce learning.

  4. Relate Genes and Pathways: Understand signaling pathways and gene regulation, including Hox genes, Wnt, Notch, and BMP pathways.

  5. Revision: Regularly revise key terms, processes, and diagrams for long-term retention.

Recommended Resources

  1. Developmental Biology by Scott F. Gilbert – Comprehensive textbook for conceptual clarity.

  2. Lippincott’s Illustrated Reviews: Developmental Biology – Excellent for diagrams and concise explanations.

  3. CSIR NET Previous Year Question Papers PDF – For practice and exam pattern analysis.

  4. Online Test Series and Video Lectures – Useful for learning mechanisms and improving problem-solving speed.

Conclusion

Mastering Basic Concepts of Development is vital for CSIR NET Life Science aspirants. Regular practice of previous year questions and solutions strengthens conceptual understanding, improves exam confidence, and enhances accuracy.

Tip: Dedicate 20–30 minutes daily to solving PYQs on development, make concise notes, and practice diagrams to maximize your score.

69. The flowering repressor gene that is responsible for the vernalization requirement in Arabidopsis is: (1) CONSTANS (CO) (2) FLOWERING LOCUS D (FD) (3) FLOWERING LOCUS T (FT) (4) FLOWERING LOCUS C (FLC)

FLOWERING LOCUS C (FLC): The Key Repressor Gene Responsible for Vernalization Requirement in Arabidopsis

Given below are the list of proteins (Column X) and their functions (Column Y) during floral induction. Which one of the following options represents the correct match between column X and column Y? (1) A - i, B - ii, C - iii, D - iv (2) A - iii, B - iv, C - i, D – ii (3) A - ii, B - i, C - iv, D – iii (4)A - iv, B - iii, C - ii, D – i 

Key Proteins and Their Functions in Floral Induction: Correct Matching in Arabidopsis thaliana

In most angiosperms, flowers have a perianth that consists of whorls of organs. Select the statement that is INCORRECT about the floral organs in angiosperms. (1) All petals are not homologous (2) If there is only one whorl of organs, these structures are referred to as tepals (3) Sepals tend to be initiated almost simultaneously and never in a spiral sequence. (4) Both sepals and petals can act as protective organs for inner floral organs and also as organs to attract pollinators 

Understanding Floral Organ Development in Angiosperms: Correcting Common Misconceptions

66. Which one of the following options related to plant growth and development is matched correctly? (1) LEAFY: regulator of genomic imprinting (2) Xylogenesis: wood formation (3) FLOWERING LOCUS T (FT) (4) FLOWERING LOCUS C (FLC)

Understanding Xylogenesis: The Process of Wood Formation in Plants

65. AP1 (APETLA 1) is one of the floral meristem identifying genes. In wild type Arabidopsis thaliana plants transformed with AP1:GUS, β glucuronidase (GUS) activity is seen in floral meristem, only after the commitment to flowering. Ectopic expression of AP1::GUS in the EMBRYONIC FLOWER (emf) mutant background results in GUS activity throughout the shoots in four day old seedlings. These observations suggest that AP1 is: - (1) not involved in flowering (2) involved in repression of flowering. (3) involved in promoting flowering. (4) stimulation of flowering in the emf background 

the Role of APETALA1 (AP1) in Promoting Flowering and Floral Meristem Identity in Arabidopsis

Flowers represent a complex array of functionally specialized structures that differ substantially from the vegetative plant body in form and cell types. Following are statements made regarding floral meristems. A. Floral meristems can usually be distinguished from vegetative meristems by their larger size. B. The increase in the size of the meristem is largely a result of increased rate of cell division in central cells. C. The increase in the size of the meristem is due to larger size of the cells, which in turn results from rapid cell expansion only. D. A network of genes control floral morphogenesis in plants. Which combination of the above statements is true? (1) A, B and D (2) A, Band C (3) B, C and D (4) A, C and D 

Genetic and Cellular Control of Floral Meristem Development and Morphogenesis in Plants

63. Which one of the following statements about LEAFY (LFY), a regulatory gene in Arabidopsis thaliana, is correct? (1) LEAFY (LFY) is involved in floral meristem identity (2) LEAFY (LFY) is involved in leaf expansion. (3) LEAFY (LFY) 'is involved in root meristem identity. (4) LEAFY (LFY) is responsible far far-red light mediated seedling growth 

LEAFY (LFY) as a Master Regulator of Floral Meristem Identity in Arabidopsis thaliana

The control of flowering is a complex process involving several key regulatory genes. Some statements on flower development are given below: A. Two major types of genes regulate floral development: meristem identity genes and floral organ identity genes. B. The important genes in Arabidopsis that play key regulatory roles in meristem identity are: APETALA1, LEAFY and SUPPRESSOR OF CONSTANS1. C. The genes that determine floral organ identity were discovered as floral homeotic mutants. D. Most plant homeotic genes belong to a class of related sequences known as FAD box genes. Which one of the following combinations of the above statements is correct? (1) A, B and C (2) B, C and D (3) A, C and D (4) A, B and D 

APETALA2 Gene Expression in Sepal and Petal Development: Verification from the ABC Model of Arabidopsis Flowering

According to the ABC model of floral development in Arabidopsis as shown below Several genes/transcription factors e.g. AP 1, AP2, AP3, AG etc., are involved. Which one of the following statements is correct? (1) Apetala 2 (AP2) transcripts expressed during sepal and petal development. (2) Agamous AG is considered as class A gene. (3) AP1 expressed during carpel development. (4) AP3 expressed during sepal development. 

Expression and Role of APETALA2 in Sepal and Petal Development in Arabidopsis Flower

60. Which one of the following plant homeotic genes does NOT encode MADS- domain transcription factor involved in floral organ specification? (1) AP2                                                         (2) AP1 (3) AP3/P1                                                     (4) AG 

APETALA2: A Non-MADS-Domain Transcription Factor in Floral Organ Specification

Individual and overlapping expression of homoerotic genes in adjacent whorls of a flower determine the pattern of floral organ development. In an Arabidopsis mutant, floral organs are distributed as follows: Whorl 1 (outer most) — carpel Whorl 2 — stamens Whorl 3 – stamens Whorl 4 (inner most) — carpel Loss of function mutation in which one of the following genes would have caused the above pattern of floral organ development? (1) APETALA 2 (2) APETALA 3 (3) PISTILLATA (4) AGAMOUS 

Understanding the Role of AGAMOUS in Floral Organ Development and Mutant Phenotypes in Arabidopsis

58. Following are certain statements regarding the activities of homeotic genes of classes A, B and C involved in floral organ identity: A. Activity of A alone specifies sepals B. Activity of B alone specifies petals C. Activities of B and C form stamens D. Activity of C alone specifies carpels Which one of the following combinations of above statements is correct? (1) A, B and C                                                (2) A, B and D (3) B, C and D                                                (4) A, C and D 

Understanding the ABC Model of Floral Organ Identity: Roles of Class A, B, and C Genes in Arabidopsis

Based on ABC model during flower development, loss of class A activity results in the formation of only stamen and carpel. Which of the following floral organ identity genes controls the class A activity? (1) APETALA 1 and APETALA 2 (2) APETALA 3 and PISTILLATA (3) Only PISTILLATA (4) Only AGAMOUS 

APETALA1 and APETALA2: Key Regulators of Class A Activity in Arabidopsis Floral Organ Development

56. In Agamous mutant (flower within flower phenotype) which of the following statements is valid? (1) Class A genes are expressed in the first two whorls, Class B genes are expressed in the second and third whorls and Class C genes are expressed in the third and fourth whorls. (2) Class A genes are not expressed. Class B and C genes are expressed in all the whorls. (3) Class A genes are not expressed. Class B genes are expressed in the second and the third 

Understanding AGAMOUS Mutant Phenotype and Gene Expression Patterns in Arabidopsis Floral Development

Plants with apetala2 mutation show a phenotype that lacks (1) sepals only. (2) both sepals and petals. (3) petals only. (4) stamens only.

Role of APETALA2 Gene in Sepal and Petal Development in Arabidopsis Flowers

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants? (1) Sepals and petals. (2) Petals and stamens. (3) Stamens and carpels. (4) Sepals and stamens. 

Impact of APETALA3/PISTILLATA Mutation on Petal and Stamen Development in Arabidopsis Flowers

Which of the floral whorls is affected in agamous (ag) mutants (1) Sepals and petals (2) Petals and stamens (3) Stamens and carpels (4) Sepals and carpels 

AGAMOUS Gene Function in Floral Organ Development: Impact on Stamens and Carpels

Floral organ development is controlled by overlapping expression of 'A' class, 'B' class and 'C' class genes in different whorls. In an Arabidopsis mutant, the flowers had sepals, sepals, carpels and carpels in the four whorls. Mutation in which one of the following is the cause for the mutant phenotype? (1) 'A' class gene alone (2) 'B' class gene alone (3) 'A' and 'B' class genes (4) 'C' class gene alone 

Impact of B-Class Gene Mutation on Floral Organ Identity in Arabidopsis: The ABC Model Explained

51. Among the following which gene product migrates from leaves to shoot meristem during transition of shoot meristem into floral meristem? (1) Flowering locus T                             (2) Flowering locus D (3) Leafy                                                       (4) Apetala 1

Role of Flowering Locus T (FT) as a Mobile Signal from Leaves to Shoot Apical Meristem in Floral Transition

In plants gene 'sepallata' is NOT involved in formation of organ (1) Sepals (2) Petals (3) Stamens (4) Carpels 

Role of SEPALLATA Genes in Floral Organ Development: Excluding Sepals from SEP Function

Three classed of genes A, B and C regulates the development of flower in Arabidopsis. If a loss-of-function mutation occurs in the B-type genes, what will be the composition of the flower whorls? (1) sepals-petals-stamens-carpels (2) sepals-sepals-stamens-carpels (3) sepals-sepals-carpels-carpels (4) petals-petals-stamens-stamens 

Impact of B-Type Gene Mutation on Flower Whorl Composition in Arabidopsis: Understanding the ABC Model

Organ Identity genes are responsible for correct positioning of floral organs on floral meristem. Mutation in them will lead to (1) Loss of all organs from whorls (2) More number of organs in certain whorls (3) Appearance of organs at incorrect positions (4) No flower 

Role of Organ Identity Genes in Floral Organ Positioning and Development

Light signals for flowering is received by (1) Flower bud (2) Apical bud (3) Leaves (4) Flower bract 

Leaves as Primary Photoreceptors for Flowering Signal Reception in Plants

46. Following are certain statements regarding root growth and differentiation in plants: A. Root hair, endodermis, xylem and phloem reach maturation in elongation zone of a developing root. B. The root epidermal cells that are incapable of forming root hairs are called atrichoblasts. C. Quiescent center is present just above root cap. D. In Arabidopsis, an auxin transporter (ABCB4) plays a role in root hair emergence by maintaining intracellular auxin concentration. Which one of the following combination of statements is correct? (1) A, B and C                                                (2) B, C and D (3) A, C and D                                                (4) A, B and D

Root Growth and Differentiation: Role of Atrichoblasts, Quiescent Center, and ABCB4-Mediated Auxin Transport

Given below are statements related to different aspects of plant growth and development. A. Leaf longevity is increased in ethylene insensitive mutants eir1-1 and ein2 of Arabidopsis. B. Programmed cell death (PCD) is responsible for the formation of prickles, thorns and spines in plants. C. Senescence and PCD occur only in the development of vegetative tissues and does not occur in reproductive tissues D. Re-differentiation of organelles is an integral component during initial stages of senescence in plants. Which one of the following represents the combination of all correct statements? (1) A, C and D (2) B and C (3) A, B and D (4) C and A 

Ethylene Insensitivity, Programmed Cell Death, and Organelle Redifferentiation in Plant Growth and Senescence

Change in leaf morphology is observed during transition from vegetative to reproductive phase in several plants. The following statements are proposed to explain the above observation: A. Alteration in the gene content of leaves of reproductive phase from those of vegetative phase. B. Differential methylation pattern of genes influencing leaf development and morphology. C. Mutation in transcription factor that prevents its association with promoter elements of genes regulating leaf development. D. Small RNA mediated inhibition of gene expression of a homeotic gene. Which one of the following options represents a correct combination of statements that could explain the observed changes? (1) B and C (2) A and D (3) B and D (4) A and C 

Epigenetic and Small RNA Regulation of Leaf Morphology During Vegetative to Reproductive Phase Transition in Plants

43. Given below are factors/terms associated with various aspects of plant growth and development: Which one of the following options represents the most appropriate match between all terms of Column A and Column B? (1) A-ii, B-iii, C-iv, D-l                                       (2) A-iii, B-, C-iv, D-ii (3) A-ii, B-iv, C-, D- iii                                                (4) A-iv, B-i, C-ii, D-iii

Key Factors in Plant Growth and Development: Photosynthesis, Hormones, Nutrition, and Cytoskeletal Dynamics

42. Genetic screens for mutants affecting development of leaf trichomes have led to the discovery of genes regulating trichome patterning - especially trichome density and spacing, as depicted in the figure below.42. Genetic screens for mutants affecting development of leaf trichomes have led to the discovery of genes regulating trichome patterning - especially trichome density and spacing, as depicted in the figure below. The following statements are made in this regard: A. GLABRAI (GLI) mutant plant will show fewer or no trichomes. B. Cells that form trichomes strongly express the GLABRA2 (GL2) and TRYPTICON (TRY) genes. C. TRY protein acts as a positive regulator of trichome cell differentiation in the surrounding cells. D. Addition of exogenous JA will reduce the number of leaf trichomes. Which one of the following options represents the combination of all correct statements? (1) A and B                                                    (2) B and C (3) C and D                                                    (4) A and D

Genetic Regulation of Leaf Trichome Development in Arabidopsis: Roles of GL1, GL2, TRY, and Jasmonic Acid

41. The following diagram represents a longitudinal section through an Arabidopsis shoot apical meristem (SAM) and leaf primordium at its flank. The dorsal (D) and ventral (V) domains are marked. The D and V genes are expressed in the dorsal and ventral domains, respectively Consider the following statements describing the phenotypes of leaf polarity. A. Loss of D function makes the leaf ventralized whereas its overexpression dorsalizes the leaf. B. Loss of V function makes the leaf dorsalized whereas its overexpression ventralizes the leaf. C. Loss of microRNA miR166 dorsalizes the leaf whereas its overexpression ventralizes the leaf. D. miR166 functions by inhibiting its target mRNA. Which one of the following functional models best describes the above results?

Genetic Regulation of Leaf Polarity in Arabidopsis: Roles of D Genes, V Genes, and miR166

Members of the WUSCHEL RELATED HOMEOBOX (WOX) transcription factor family play an important role during zygote elongation and division in Arabidopsis. Following are certain statements regarding the expression of different members of WOX gene family during zygote elongation. (A) WOX2 and WOX8 are present in both the egg cell and the zygote. (B) WOX2 is present in the apical and basal cell. (C) WOX8 along with WOX9 regulates the development of basal lineage. (D) WOX8 and WOX9 are directly activated in the zygote by the transcription factor WRKY2. Which one of the following options represents combination of all correct statements? (1) A, B and C (2) A, B and D (3) A, C and D (4) B, C and D 

Role of WOX Gene Family and WRKY2 in Arabidopsis Zygote Elongation and Early Embryo Patterning

39. Consider the following facts regarding the control of shoot apical meristem (SAM) size in Arabidopsis (a) Loss of the CLAVATA1 (CLV1) gene leads to bigger SAM (b) Loss of the CLAVATA3 (CLV3) gene leads to bigger SAM (c) Loss of the WUSCHEL (WUS) gene leads to smaller SAM (d) Loss of both CLV1 and WUS leads to smaller SAM (e) Loss of both CLV3 and WUS leads to smaller SAM (f) Loss of both CLV1 and CLV3 leads to bigger SAM (g) Over expression of CLV3 leads to smaller SAM (h) Over expression of CLV3 in the loss of function mutant of CLV1 leads to bigger SAM. Based on the above information, which of the following genetic pathways describes the   relationship among CLV1, CLV3 and WUS most appropriately

CLAVATA-WUSCHEL Feedback Regulation in Arabidopsis Shoot Apical Meristem Size Control

38. Extensive molecular genetic studies on miR156, miR172, SPL genes and AP2- like genes have yielded the following functional model on the juvenile → adult → reproductive transition in Arabidopsis Based on these results, the following schematic diagram has been proposed to predict the expression kinetics of these genetic factors: Which of the following combinations is most likely to be correct? (1) a-miR156; b-SPL genes; c -miR172; d - AP2 like genes (2) a-miR156; b-miR172; c-:-SPL genes; d - AP2 like genes (3) a-miR 172; b-SPL genes; c-AP2 like genes; d-miR156 (4) a-miR156; b-AP2 like genes; c. miR172; d-SPL genes

Genetic Regulation of Juvenile to Adult and Reproductive Phase Transition in Arabidopsis: Roles of miR156, SPL Genes, miR172, and AP2-like Genes

Identification of genes that are associated with the development of male and/or female gametophyte and embryogenesis in plants is facilitated by T-DNA mediated insertional mutagenesis. In an experiment, a transgenic plant was generated by insertion of T-DNA (containing a Kanamycin-resistance gene) into a gene "A". Self-pollination of the To plant generated F1 progeny that segregated in a 2 : 1 ratio for resistance : sensitivity to Kanamycin. These observations indicate that (1) the mutant allele did not segregate from the wild type allele. (2) mutation in gene "A" induces lethality in the male gametophyte. (3) mutation in gene "A" induces lethality in the female gametophyte. (4) mutation in gene "A" induces zygotic lethality. 

T-DNA Insertional Mutagenesis in Arabidopsis: Understanding Zygotic Lethality Through Segregation Distortion

36. Mutation in a gene x in Arabidopsis thaliana results in more number of lateral root formation. Which one of the following is the correct statement? (1) The gene product acts as a positive factor of lateral root formation. (2) The gene product acts as a negative regulator of lateral root formation. (3) The gene product is not likely to be involved in lateral root formation. (4) The gene product promotes replication for lateral root development 

Gene Regulation of Lateral Root Formation in Arabidopsis: Negative Regulators and Mutant Phenotypes

35. Which one of the following root initials gives rise to the root vascular system, including the pericycle? (1) Columella initials (2) Epidermal-lateral root cap initials (3) Cortical-endodermal initials (4) Stele initials 

Stele Initials: Originators of the Root Vascular System and Pericycle in Higher Plants

34. The group of cells which generates the vascular tissues including the pericycle in roots of higher plants are called (1) procambium.                                            (2) protoderm. (3) ground meristem.                                                            (4) apical meristem.

Procambium: Origin and Role in Vascular Tissue Development in Roots of Higher Plants

The following statements have been proposed for plant vegetative development: (A) Lateral roots develop from epidermal cells. (B) Shoots axillary meristem develops from shoot apical meristem during differentiation of leaf primordia. (C) Root cap is made of dead cells. (D) Lateral meristem and cylindrical meristem found in roots and shoots results in secondary growth. Which of the above statements are true? (1) (A) and (B) (2) (B) and (D) (3) (A), (B) and (D) (4) (C) and (D) 

Vegetative Development in Plants: Root Cap Cells and Secondary Growth by Lateral Meristems

32. Due to the presence of cellulose in the cell wall of plants, leaf shape is determined in the leaf primorida by (1) rates of cell division. (2) planes of cell division. (3) cell migration. (4) cell-cell interactions. 

Role of Cell Division Planes in Determining Leaf Shape in Plants

31. Following are certain statements regarding seed development in plants: A. During final phase of development embryo's of "orthodox" seeds became tolerant to desiccation, dehydrate losing up to 90% of water B. Dormant seeds will germinate upon rehydration while quiescent seeds require additional treatments or signals for the germination C. Precocious germination is germination of seeds without passing through the normal quiescent and/or dormant stage of development D. Abscisic acid is known to inhibit precocious germination Which one of the following combinations is correct? (1) A, B and C                                                          (2) A, B and D (3) B, C and D                                                         (4) A, C and D 

Seed Development in Plants: Desiccation Tolerance, Dormancy, and Precocious Germination

Following statements are made in relation to the five widely recognized stages of Arabidopsis embryogenesis: A. The fusion of haploid egg and sperm takes place in globular stage B. Rapid cell division in two regions on either side of the future shoot apex forms heart stage C. The cell elongation throughout the embryo axis and further development result in torpedo stage D. The embryo loses water and becomes metabolically inactive in the zygotic stage Which combination of the above statements is correct? (1) A and B (2) B and C (3) C and D (4) D and A 

Key Stages of Arabidopsis Embryogenesis: Heart and Torpedo Morphogenesis Explained

In which of the following stages of Arabidopsis embryogenesis do the visible distinctions between the adaxial and abaxial tissues of the cotyledons become initially apparent? (1) Globular stage (2) Zygotic stage (3) Torpedo stage (4) Mature stage 

Torpedo Stage of Arabidopsis Embryogenesis: First Visible Adaxial-Abaxial Tissue Differentiation in Cotyledons

In which stage of Arabidopsis embryogenesis is hypophysis first observed? (1) Octant (2) Dermatogen (3) Globular (4) Transition 

Globular Stage of Arabidopsis Embryogenesis: Initial Appearance of Hypophysis and Root Meristem Formation

During which one of the following stages of Arabidopsis embryogenesis, cell elongation throughout the embryonic axis and further development of the cotyledons occur? (1) Globular stage. (2) Torpedo stage. (3) Heart stage. (4) Mature stage. 

Torpedo Stage of Arabidopsis Embryogenesis: Cell Elongation and Cotyledon Development

During development of embryos in plants, PIN proteins are involved in (1) establishment of auxin gradients (2) regulation of gene expression (3) induction of programmed cell death (4) induction of cell division 

Role of PIN Proteins in Establishing Auxin Gradients During Plant Embryo Development

In mature Arabidopsis embryo, root apical meristem consists of cells derived from (1) embryo and apical suspensor cells (2) embryo only (3) suspensor only. (4) hypophysis only. 

Origin of Root Apical Meristem in Arabidopsis: The Role of Hypophysis

Distyly is A. presence of two styles in a flower B. presence of two lengths of styles in a species C. a form of dichogamy. D. a form of herkogamy. Which one of the following options represents all correct statements? (1) B only (2) A and C (3) B and C (4) B and D 

Distyly in Flowering Plants: Floral Dimorphism and Reciprocal Herkogamy Explained

23. Autogamy refers to (1) self-abortion of gametes (2) flower failing to open (3) self-pollination of flowers (4) cross-pollination of flowers 

Autogamy in Plants: Self-Pollination Mechanism and Its Biological Significance

In certain plants, the mechanism where timing of anther dehiscence and stigma receptivity do not coincide to avoid self-pollination is called (1) dichogamy (2) herkogamy (3) monoecy (4) Dioecy 

Dichogamy in Plants: Mechanism for Avoiding Self-Pollination Through Temporal Separation

21. Given below are statements regarding apomixis, i.e. asexual reproduction through seeds Sporophytic apomicts often produce a mix of clonal and sexual progeny B. In gametophytic apomixis, the unreduced central cell gives rise to apomictic embryo C. In pseudogamy the endosperm is formed in the absence of fertilization D. Apomixis can potentially be used to maintain hybrid vigour over many generations Which one of the following options represents the combination of all correct statements? (1) A and C (2) B and C (3) C and D (4) A and D

Key Features of Apomixis in Plants: Sporophytic Apomixis and Maintenance of Hybrid Vigor

20. Following are certain statements regarding apomixis in plants: A. Apomixis cannot be used to maintain hybrid vigor over many generations in plants. B. In sporophytic apomixis maternal genotype is maintained. C. There is an event of meiosis during gametophytic apomixis and is also referred as apomeiosis. D. In diplospory, meiosis of the megaspore mother cell is aborted, resulting in two unreduced spores, out of which one forms the female gametophyte. Which one of the following combinations is correct? (1) A and B                                                    (2) A and C (3) B and C                                                    (4) B and D 

Understanding Apomixis in Plants: Maintenance of Maternal Genotype and Apomeiosis in Diplospory

Match the two columns following asexual reproduction of plants and apomixes: (1) A - (i); B - (ii); C - (iii); D - (iv) (2) A - (ii); B - (iii); C - (iv); D - (i) (3) A - (ii); B – (i); C - (iii); D - (iv) (4) A - (ii); B – (i); C - (iv); D - (iii) 

Asexual Reproduction in Plants: Types and Mechanisms of Apomixis Explained

During embryo germination in a grass family an absorptive organ that forms interface between the embryo and the starchy endosperm tissue is called (1) Coleorhiza (2) Coleoptile (3) Scutellum (4) Mesocotyl 

Role of Scutellum in Grass Seed Germination: Nutrient Absorptive Organ Connecting Embryo and Endosperm

17. A few statements on early developmental stages in plants are given below: A. The cells of flower are diploid in nature. B. Only some specialized cells in reproductive organs undergo meiosis produce haploid cells. C. The haploid cells produced in (B) above, undergo a few normal mitotic cell divisions. D. All the progeny cells produced in (B) above, differentiate either into haploid egg cells or into haploid sperm cells. Which one of the following combinations of above statements is correct? (1) A, B and C                                                (2) B, C and D (3) A, C and D                                                (4) A, B and D

Early Plant Developmental Stages: Meiosis, Mitosis, and Gamete Formation

The development of anthers and male gametophytes is highly conserved among angiosperms. Following are some of the events associated with pollen development, in random order. (a) Microsporogenesis in pollen sac to produce a tetrad. (b) Asymmetric division forming immature pollen grain. (c) Archespore division. (d) Division of generative cell to form two sperm cells. (e) Callose digestion to form free microsperes. Which of the following option represent the correct series of events during pollen development? (1) (a), (b), (c), (d), (e) (2) (c), (a), (e), (b), (d) (3) (a), (c), (d), (b), (e) (4) (c), (e), (a), (b), (d) 

Stages of Pollen Development in Angiosperms: From Archespore to Mature Gametophyte

Which of the following statement is WRONG? (1) Megasporocyte develops within the megasporangium of the ovule (2) Megasporocyte undergoes meiosis to produce four haploid megaspores (3) All the four megaspore undergo several mitotic division to form female gametophyte in most angiosperms (4) Female gametophyte is haploid 

Megasporogenesis and Female Gametophyte Development in Angiosperms: Clarifying Common Misconceptions

Which one of the following statements regarding double fertilization in plants is correct? (1) The same sperm cell fuses with both egg cell and central cell. (2) Two sperm cells fuse with the egg cell. (3) One sperm cell fuses with the egg cell and second with the central cell. (4) Two sperm cells fuse with the central cell. 

Double Fertilization in Plants: Fusion of Sperm with Egg and Central Cell Explained

Sperm cell behaviour during double fertilization in Arabidopsis can be stated as follows. Identify the INCORRECT statement: (1) Pollen tube bursts and discharges sperm cells. (2) Pollen cells produce pollen tubes and enter into female gametophyte. (3) The receptive antipodal cells break down when pollen tube enters the female gametophyte. (4) One sperm nucleus fuses with the egg cell and the other fuses with the central cells. 

Sperm Cell Behavior in Arabidopsis Double Fertilization: Correcting Misconceptions About Antipodal Cells

During reproductive development in plants: (A) male and female gametes are produced as a result of two mitotic divisions after meiosis (B) vegetative cells in pollen contribute to pollen development (C) antipodal provide nourishment to developing embryo (D) Pollen tube ruptures and releases both the male gametes in one of the degenerated synergids Which of the above statement are true? (1) A and B (2) B and D (3) B and C (4) A and D 

Plant Reproductive Development: Roles of Vegetative Cells, Synergids, and Gamete Formation

During double fertilization in plants, one sperm fuses with the egg cell and the other sperm fuses with (1) synergid cell (2) central cell (3) antipodal cell (4) nucellar cell 

Double Fertilization in Angiosperms: Fusion of Sperm with Egg and Central Cell

10. In Arabidoposis gene responsible for formation shoot meristem is (1) Leafy                                                       (2) Agamous (3) Clavata                                                    (4) Wus 

WUSCHEL Gene: Master Regulator of Shoot Meristem Formation in Arabidopsis

Which one of the following transcription factors is important for delimiting the meristematic and elongation zones of roots? (1) SCARECROW (SCR) (2) SHORT ROOTS (SHR) (3) PLETHORA (PLOT) (4) SPEECHLESS (SPCH)

Role of PLETHORA Transcription Factor in Root Meristem and Elongation Zone Regulation

Which would be the result of mutation in SCARECROW genes responsible for radial patterning in roots of higher plants? (1) No apical root formation (2) Root hair will fail to develop (3) Roots with missing cell layer that normally generates cortex and endodermis. (4) Roots will be positively geotropic 

Role of SCARECROW Gene in Root Radial Patterning: Effects of Mutation on Cortex and Endodermis Formation

Which of the following represents the gametophyte generation in plants (1) Ovule (2) Megaspore (3) Embryo sac (4) Egg 

Understanding the Gametophyte Generation in Plants: The Role of the Embryo Sac

In plant lateral root initiates from (1) Pericycle (2) Cortex (3) Pith (4) Endodermisv

Origin of Lateral Roots in Plants: Role of the Pericycle in Root Development

Factor responsible for formation of embryonic axis during early developmental pathway of plant is (1) Auxin gradient (2) Morphogens (3) Orientation of embryo sac (4) Plane of Cell Division 

Role of Auxin Gradient in Embryonic Axis Formation During Early Plant Development

During gametophytic self-incompatibility the primary response is (1) The interaction between the SRK and SCR/SP11 and downstream cellular and molecular events, leading eventually to pollen inhibition (2) S-RNase probably causes degradation of the ribosomal RNA (rRNA) inside ovule of female plant (3) Formation of concentric ring from Golgi (4) Ca2+-dependent signaling cascade in incompatible pollen inhibiting elongation 

Gametophytic Self-Incompatibility: Molecular Mechanism of SRK and SCR/SP11 Interaction Leading to Pollen Inhibition

The development of sporophyte directly from gametophytic tissue without fusion of gametes is termed as (1) Apogamy (2) Apospory (3) Adventive embryony (4) Apomixis

Apogamy in Plants: Asexual Development of Sporophyte from Gametophyte Without Fertilization

Generally the number of cells present in gametophyte of angiosperm are- (1) 7 (2) 8 (3) 3 (4) 5 

Cellular Structure of Angiosperm Gametophytes: Understanding the 7-Cell Female Gametophyte

1. Apomixis is reproduction in which (1) Fusion of gametes but no fusion of central cell (2) Egg form complete plant (3) Pollen forms seeds (4) Seeds are formed without union of gametes

Apomixis in Plants: Asexual Seed Formation Without Fertilization

67. In the avian embryo, the blastocoel-like fluid-filled cavity is formed between: (1) epiblast and hypoblast (2) hypoblast and yolk (3) primary hypoblast and secondary hypoblast (4) Koller's sickle and Posterior Marginal Zone 

Formation and Role of the Blastocoel-like Cavity in Avian Embryo Development

The early embryonic development in amphibians and aves serve as two different model plans of development. In the former the germ layer formation is initiated from a fluid-filled ball like blastula, while in the latter the germ layer formation is initiated on a flat blastodisc. Given below are some of the terms for amphibian embryo in column l and from avian embryo in column ll: Which of the following is the all correct match of the terms in Column l with that of Column ll? (1) A-iv, B-iii, C-ii, D-v, E-l (2) A-iv, B-ii, C-iii, D-v, E-i (3) A-v, B-i, C-ii, D-iv, E-iii (4) A-i, B-ii, C-iii, D-iv, E-v 

Comparative Terms in Amphibian and Avian Embryonic Development: Blastocoel, Primitive Streak, and Organizer Equivalents

65. The major structural characteristic of avian gastrulation is the primitive streak, which becomes the blastopore lips of amniotic embryos. Migration through the primitive streak is controlled by Fgf8. What would happen if the Fgf8 protein, which repels migrating cells away from the streak, is over expressed in the primitive streak? (1) The yolk sac will be deformed. (2) Wnt signalling will be activated and orientation of the primitive streak will change (3) Cells of the streak will not form the paraxial mesoderm. (4) Cells generate mesodermal portions of the embryo

Impact of Fgf8 Overexpression on Primitive Streak and Mesoderm Formation during Avian Gastrulation

Following statements were made about the events occurring during chick development. A. The fertilized chick egg undergoes discoidal meroblastic cleavage; however the cleavage does not extend into the yolk cytoplasm. B. Development of primary hypoblast is mediated by localized migration of a group of highly specified and connected cluster of 30-40 cells. C. By the stage XIII of chick embryogenesis and little prior to primitive streak formation, the formation of the hypoblast is just complete. D. Hansen's node of the chick embryo signifies a region at the anterior end of the primitive streak with regional thickening of cells. E. Inhibition of Wnt planar cell polarity pathway in the epiblast causes the mesoderm and endoderm to form centrally instead of peripherally. Which one of the following combinations represents all correct statements? (1) A, B and D (2) A, C and E (3) A, B and C (4) A, C and D 

Key Events in Chick Embryogenesis: Cleavage, Hypoblast Formation, Primitive Streak, and Hensen’s Node

Hensenis node is established as the avian equivalent of the amphibian dorsal blastopore lip. The following observations are presumed to be support of the same. A. It is the region whose cells induce and pattern a second embryonic axis when transplanted into other locations of the gastrula. B. It is equivalent in terms of tissue structure. C. It expresses the same marker genes as the Spemann's organizer in Amphibians. D. The same micro RNA can interfere with the formation of pre-chordal plate in both Hensen's node and Spemann's organizer. Choose the correct set among the following: (1) A and D (2) A and C (3) B and C (4) A and B 

Hensen’s Node as the Avian Equivalent of the Amphibian Spemann Organizer: Axis Induction and Genetic Markers

The part of the embryo from which the ectoderm, mesoderm and endoderm are formed in chick is known as (1) primitive streak (2) hypoblast (3) epiblast (4) cytotrophoblast 

Chick Embryo Germ Layer Formation: Role of the Epiblast and Primitive Streak in Early Development

Cells from an early frog blastula were remove from the animal pole and used to replace cells from the vegetal pole of the blastula. The following events may be expected. A. Transplanted cells would develop normally as part of the cells of the vegetal pole. B. Transplanted cells would develop as cells of the animal pole of the adult on the vegetal pole. C. Region of the animal pole from where the cells were removed would be missing in the adult. D. Remaining cells in the animal pole would compensate for the cells that were removed. Which of the following are true? (1) B, C and D (2) A, B and D (3) A, B and C (4) A, C and D 

Fate and Compensation of Frog Blastula Cells: Animal Pole to Vegetal Pole Transplantation Outcomes

In an experiment, activin-secreting beads were placed on unspecified cells from an early Xenopus embryo. The activin then diffused from the beads. If the beads contained 1nM of activin, it elicited expression of Xbra gene in cells near to the beads. If the beads contained 4 nM activin, the expression of Xbra was elicited in cells, but only at a distance of several cell diameters away from the beads. In the latter case, expression of goosecoid gene was observed near the source bead. Beads with no activin did not elicit the expression of the two genes. Following statements were made regarding the observations and the role of activin in determining cell fate. A. High concentration of activin activates goosecoid, whereas lower concentrations activate Xbra. B. Lower concentrations of activin help specify the dorsal-most structures of the frog's embryo C. Concentrations of activin that do not lead to expression of the two genes specifies the cell to become blood vessels and heart Which of the above statement(s) are correct? (1) A only (2) C only (3) A and C (4) B and C 

Activin Morphogen Gradient in Xenopus: Concentration-Dependent Gene Activation and Cell Fate Specification

59. A "morphogen" can determine the fate of a cell by its concentration. Given below are some statements on the experiment performed to study the gradient- dependent effect of the morphogen, activin on cell fate by placing activin (4 nm)-secreting beads on unspecified cells from an early Xenopus embryo: A. Beads without activin did not elicit expression of either Xbra or goosecoid genes. B. Cells nearest to the beads getting highest concentration of activin induced goosecoid gene whose product is a transcription factor, specifies the frog's dorsal-most structures. C. Cells nearest to the beads getting highest concentration of activin induced Xbra gene whose product is a transcription factor, specifies the frog's dorsal-most structures. D. Cells farthest from the beads getting negligible activin activate Xbra gene and become blood vessels and heart E. Cells farthest from the beads getting negligible activin, activated neither Xbra nor goosecoid and the default gene expression instructed the cells to become blood vessels and heart. Which of the above observations and conclusions drawn are correct? (1) A, B and C                                                          (2) B, C and D (3) C, D and E                                                          (4) A, B and E

Activin Morphogen Gradient in Xenopus: Differential Gene Activation and Cell Fate Determination

In Xenopus, the Noggin protein, accomplishes two major functions of the organizer: it induces dorsal ectoderm to form neural tissues, and it dorsalizes mesoderm cells. Which one of the following observations is correct with respect to Noggin? (1) If a plasmid clone expressing Noggin protein is microinjected into a lithium chloride treated Xenopus gastrula, it should rescue the abnormalities induced by lithium chloride treatment. (2) If a plasmid clone expressing Noggin protein is microinjected into UV-treated embryo which does not give rise to neural tube, it will rescue the abnormality. (3) RNA in situ hybridization of noggin cDNA on Xenopus embryo will show its presence in all regions except the dorsal blastopore lip. (4) Microinjection of noggin mRNA into the embryo region fated to make the ventral part will promote its ventralization. 

Noggin in Xenopus Embryos: Rescuing Dorsal Structures and Neural Tube Formation after UV Treatment

Injection of Noggin mRNA in cells that will become the future ventral side of a frog embryo mimics the effect of an organizer graft to the ventral side. This experiment demonstrates that A. Noggin is a transcription factor B. Noggin induces ventral fates C. Noggin is involved in organizer fate D. Noggin is required to induce a secondary axis Which one of the following options represents correct combination of statement/s? (1) A and C (2) C and D (3) A and B (4) B and C 

Noggin mRNA Injection in Frog Embryos: Mimicking Organizer Function and Inducing Secondary Axis Formation

56. The following statements are made regarding the amphibian early-embryonic development: A. The Nieuwkoop center cells are mesodermal in origin. B. Chordin, Noggin and Goosecoid are secreted by the Organizer. C. The default fate of the ectoderm is to become neural tissue. D. BMP levels are high in the presumptive dorsal mesoderm.

Understanding Amphibian Early Embryonic Development: Nieuwkoop Center, Organizer Secretions, Neural Induction, and BMP Signaling

Following statements are made regarding amphibian development: A. Fibronectin plays an important role in enabling the mesodermal cells to migrate into the embryo. B. Organizer secrete proteins that block the BMP signal, which allows the ectodermal cells to become epidermis. C. Wnt signalling causes a gradient of B-catenin along the anterior-posterior axis of the neural plate, which appears to specify the regionalization of the neural tube. D. The more ventral blastomeres in the endoderm have high expression of nodal-related proteins. Which one of the following options represents the combination of all correct statements? (1) A and B (2) A and C (3) B and C (4) C and D 

Roles of Fibronectin, BMP Inhibition, Wnt Signaling, and Nodal Proteins in Amphibian Development: Migration, Neural Induction, and Patterning

Which one of the following statements with respect to amphibian development is correct? (1) The organizer is itself induced by the Nieuwkoop Centre located in the dorsal most mesodermal cells. (2) The organizer functions by secreting proteins like Noggin, Chordin and Follistatin that blocks BMP signal that would otherwise dorsalize the (3) In the presence of BMP activators the ectodermal cells form neural tissue. (4) Wnt signalling causes a gradient of β-catenin along the anterior-posterior axis of the neural tube that appears to specify the regionalization of the neural tube.

Key Principles of Amphibian Development: The Nieuwkoop Centre, Organizer Function, BMP Signaling, and Wnt in Neural Patterning

52. In Xenopus embryos, β-catenin plays an important role in the Dorsal/Ventral axis development. What would you expect if the endogenous glycogen synthase kinase 3 (GSK3) is knocked out by a dominant negative form of GSK3 in the ventral cells of the early embryos? (1) Blocking of GSK3 on the ventral side has no effect. A normal embryo will form. (2) The resulting embryo will only have ventral sides (3)A second axis will form (4) The dorsal fate is suppressed. 

Dominant Negative GSK3 in Xenopus Ventral Cells: Induction of Secondary Axis and Role in Dorsal-Ventral Axis Formation

51. The presence of β-catenin in the nuclei of blastomeres in the dorsal portion of the amphibian embryo is one of the determinants for laying down the dorso-ventral axis. What will be the outcome of expressing a dominant negative form of GSK3 in the ventral cells of early embryo ? (1) The dorsal cells will be ventralized (2) A second axis will be formed (3) The primary organizer will not be formed (4) The embryo will develop normally 

Dominant-Negative GSK3 Expression in Ventral Amphibian Embryos: Mechanism, Outcome, and Axis Duplication

In amphibian oocyte, the germplasm which gets segregated during cleavage to give rise to primordial germ cells (PGC's) is normally (1) distributed evenly throughout the oocyte. (2) localized at animal pole. (3) localized at vegetal pole. (4) aggregated in central part of oocyte. 

Vegetal Pole Localization of Germplasm in Amphibian Oocytes: Key to Primordial Germ Cell Segregation

49. The dorsal-most vegetal cells of the amphibian embryo that is capable of inducing the organizer is called as Nieuwkoop centre and is marked by the presence of (1) Chordin (2) β-catenin (3) Goosecoid (4) Nanos

Nieuwkoop Center in Amphibian Embryo: Function and Molecular Markers

Which one of the following statements regarding amphibian development is correct? (1) The Nieuwkoop centre is formed on the dorsal side of the embryo due to accumulation of β-catenin which helps activate the siamois and twin genes (2) The entodermal cells form neural tissues in the presence of BMP molecules. (3) Brain formation requires the activation of both Wnt and BMP pathway. (4) There is a gradient of Nodal-related protein across the endoderm with low concentration on the dorsal side of the embryo 

Understanding Amphibian Development: The Role of the Nieuwkoop Centre and β-Catenin

In the table below Column I lists terms related to development and Column II contains their descriptions not in a sequential manner. Select the option with all correct matches between Column I and Column II. (1) A-i, B-iii, C-ii, D-iv (2) A-ii, B-i, C-iv, D-iii (3) A-iii, B-i, C-ii, D-iv (4) A-iv, B-ii, C-i, D-iii

Spemann organizer: dorsal blastopore lip mesoderm cells organizing embryo

46. The group of cells of amphibian blastula capable of inducing the organizer is called as (1) Hensen's node                                                      (2) Nieuwkoop centre (3) Dorsal blastopore lip                                  (4) Hypoblast 

Nieuwkoop Center: The Inducer of the Amphibian Organizer in Blastula Embryos

45. Which protein secreted by the amphibian organizer induces neural tissue formation by inhibiting Bone Morphogenetic Protein? (1) β-catenin.                                                 (2) Noggin. (3) Dickkopf.                                                 (4) Dishevelled.

Noggin: The Key Protein from the Amphibian Organizer that Induces Neural Tissue by Inhibiting BMP

44. In case of is Xenopus levis which cells make up the Knewkoop center and Spemann's organizer? (1) endodermal and mesodermal, respectively (2) mesodermal and endodermal, respectively (3) endodermal and ectodermal, respectively (4) ectodermal and endodermal, respectively 

Cells Comprising the Nieuwkoop Center and Spemann’s Organizer in Xenopus laevis: Endoderm and Mesoderm Explained

43. The blastopore region of amphibian embryo that secretes BMP inhibitors and dorsalizes the surrounding tissue is known as (1) Brachet's cleft                                            (2) Nieuwkoop center (3) Hensen's node                                           (4) Spemann's organizer 

Role of Spemann’s Organizer in Amphibian Embryos: BMP Inhibition and Dorsalization Explained

42. The initial dorsal-ventral axis in amphibian embryos is determined by (1) the point of sperm entry. (2) gravity. (3) the point of contact with the uterus. (4) genetic differences in the cells. 

How the Initial Dorsal-Ventral Axis Is Determined in Amphibian Embryos: The Crucial Role of Sperm Entry

The lateral separation of amphibian embryo at two celled stage will result in (1) Identical twins (2) Two embryos joined at belly region (3) Single embryo (4) Two embryos missing various organs 

What Happens When an Amphibian Embryo is Laterally Separated at the Two-Celled Stage? Identical Twins Explainedv

40. The grafting of the dorsal lip of the blastopore from an early Xenopus gastrula onto the ventral side of an early embryo will result in two complete embryos. Thus dorsal can be designated as (1) Primary organizer (2) Cytoplasmic determinant (3) Morphogen (4) Commitment

 The Role of the Dorsal Lip as the Primary Organizer in Xenopus Embryonic Development

Dorsal lip of amphibian is equivalent to chick's (1) Hensen's node (2) Primitive grove (3) Animal pole (4) Vegetal pole 

Understanding the Equivalent of the Amphibian Dorsal Lip in Chick Embryos: Hensen’s Node

38. The specification of sea urchin micromeres involves the activation of a repressor protein Pmar1, which represses the expression of hesC, which also encodes a repressor protein. One of the genes controlled by HesC is Delta, whose expression is used as a marker for micromere lineage. The image below represents a sea urchin embryo on which whole mount in situ hybridization (WMISH) was performed using delta probe, indicated by the area 'A'. The rest of the embryo is labeled 'B'. The table below summarizes a set of experiments (column A) and the area in which hybridization is observed (column B) Which one of the following options is a correct match between columns A and B? (1) A-ii, B-iii, C-l                                              (2) A-ii, B-iii, C-iv (3) A-i, B-ii, C-iv                                              (4) A-i, B-ii, C-iii

 Gene Regulatory Network and Delta Expression in Sea Urchin Micromere Specification

37. In sea urchins, a group of cells at the vegetal pole become specified as the large micromere cells. These cells are determined to become skeletogenic mesenchyme cells that will leave the blastula epithelium to ingress into the blastocoel. This specification is controlled by the expression of Pmar1 which is a repressor of HesC. HesC represses the genes encoding transcription factors activating skeleton forming genes. The gene regulatory network is given below. Below, column I lists the experiments carried with mRNA/antisense RNA of different genes injected into single-celled sea urchin embryo while column II lists the developmental outcomes: Match the following: Which of the following combinations is correct? (1) A-2, B-1, C-1, D-2                                                (2) A-1, B-1, C-2, D-2 (3) A-1, B-2, C-2, D-1                                                (4) A-2, B-2, C-2, D-2

Gene Regulatory Network Controlling Micromere Specification in Sea Urchin Embryos

Given below are few statements regarding the role of Disheveled (Dsh) and β-catenin (β-cat) in the development of sea urchin. A. Dsh is localized in the vegetal cortex of the oocyte before fertilization and in the region of the 16-cell embryo about to become the micromeres. B. Dsh is localized in the cytosol of the oocyte during oogenesis and in the micromere forming blastomeres of a 16- cell embryo. C. β-cat accumulates predominantly in the micromeres and somewhat in the veg2 tier cells. D. Treatment of embryos with lithium chloride does not allow the accumulation of β-cat in the nuclei of all blastula cells, and the animal cells thus become specified as endoderm and mesoderm. E. When β-cat is prevented from entering the nucleus, the embryo develops as a ciliated ectodermal ball. Which one of the following options represents a combination of correct statements? (1) B, C and E (2) A, C and D (3) A, C and E                                                          (4) B, D and E 

Understanding the Role of Disheveled and β-Catenin in Early Sea Urchin Embryonic Development

Following statements with respect to development in sea urchin were put forth: A. The cell fates are determined both by autonomous and conditional modes of specification. B. Large micromeres are conditionally specified. C. Large micromeres produce paracrine and juxtacrine factors that specify the fates of their neighbours. D. B-catenin is not required for the specification of the micromeres. Which one of the following options represents the combination of all correct statements? (1) A and B (2) A and C (3) C and D (4) B and D 

 Autonomous and Conditional Cell Fate Specification in Sea Urchin Embryos

Impact of GSK-3 Inhibition on β-Catenin Nuclear Accumulation and Cell Fate in Sea Urchin Embryos

33. In a given experiment, transplantation o micromeres from the vegetal pole of a 16-cell sea urchin embryo onto the animal pole of a host 16-cell sea Urchin embryo would initiate: (1) The transplanted micromeres to invaginate into the blastocoel to create a new set of skeletogenic mesenchyme cells (2) The transplanted micromeres to ingress into the blastocoel to create a new set of skeletogenic mesenchymal cells (3) The transplanted micromeres will mingle with the host micromeres to ingress into the blastocoel to create skeletogenic mesenchyme cells. (4) The transplanted micromeres will form the secondary archenteron 

Sea Urchin Micromere Transplantation: Formation of Skeletogenic Mesenchyme Cells Through Ingression

When the 4 blastomere pairs of the 8-cell stage tunicate embryo are dissociated, each forms most of the structures it would have formed had it remained in the embryo. However, the notochord and nervous system get specified only if different blastomeres get the chance to interact. Given below are certain interpretations formulated from the above results: A. Each pair of blastomeres forming respective structures indicate autonomous specification B. Each pair of blastomeres forming respective structures indicate conditional specification C. The notochord and nervous system development indicate autonomous specification D. The notochord and nervous system development indicate conditional specification. Which combination of interpretations is most appropriate? (1) A and C (2) B and D (3) A and D (4) B and C 

 Autonomous and Conditional Specification in Tunicate Embryonic Development

31. Which one of the following about development of sea urchin embryos is TRUE? (1) Each blastomere of a 4-cell stage possesses a portion of the original animal-vegetal axis and if isolated and allowed to develop will form a complete but smaller size larva. (2) Each blastomere of a 8-cell stage has the capacity to form a complete embryo but by the 16-cell stage, blastomeres will develop according to their presumptive fate. (3) Any blastomere isolated till the pluteus larva formation will regulate to go on and develop into a full sized embryo. (4) After an intricate recombination at the 16 cell stage, the resulting embryo looses its ability to form a complete larva. 

Understanding Sea Urchin Embryo Development: Cellular Potency and Axis Formation

Dreisch performed the "pressure plate experiment" to alter the distribution of nuclei in a 8-cell sea urchin embryo. He obtained normal larvae from these embryos. Following possible conclusions could be drawn: A. Prospective potency of the blastomeres is less than the actual prospective fate. B. Sea urchin embryo is a "harmonious equipotential system" implying that cell interaction is critical for normal development. C. Prospective potency of the blastomere is greater than the actual prospective fate. D. Prospective potency of the blastomere is equal to the prospective fate. Which one of the following combinations of statements represents the correct inference from the experiment? (1) A and B (2) Band C (3) B only (4) D only 

 Driesch’s Pressure Plate Experiment Reveals Equipotentiality and Potency in Sea Urchin Embryos

29. Driesch performed famous 'pressure plate" experiments involving intricate recombination with 8- celled Sea urchin embryo. This procedure reshuffled the nuclei that normally would have been in the region destined to form endoderm into the presumptive ectoderm region. If segregation of nuclear determinants had occurred, resulting embryo should have been disordered. However, Driesch obtained normal larvae form these embryos possible interpretations regarding the 8-celled sea urchin embryo are: A. The prospective potency of an isolated blastomere is greater than its actual prospective fate B. The prospective potency and prospective fate of blastomere were identical C. Sea-urchin embryo is a "harmoniously equipotential system" because all of its potentially independent parts interacted together to form single embryo. D. Regulative development occurs where location of a cell in the embryo determines its fate. Which of the interpretation(s) is/are true? (1) only A                                                      (2) only D (3) only A and B                                             (4) A, C and D 

Driesch’s Pressure Plate Experiment: Insights into Regulative Development in Sea Urchins

28. With respect to the extra embryonic structures formed in the mammals, the possible functional attributes have been designated: A. Allantoin stores urinary waste and helps mediate gas exchange. It is derived from splanchnopleure at the caudal end of the primitive streak. B. Amnion is a water sac and protects the embryo and its surrounding amniotic fluid. This epithelium is derived from somatopleure. C. Chorion is essential for gas exchange in amniote embryos. It is generated from the splanchnopleure. Yolk sac is the last embryonic membrane to form and is derived from somatopleure. Which of the above statements are correct? (1) A and B (2) A and C (3) B and C (4) A and D

Mammalian Extraembryonic Structures: Origins and Functional Roles

12. Maternal effect genes are extremely important in establishing the anterior-posterior polarity of the Drosophila embryo. Mutant phenotypes arise when genes of this family are mutated. The following table enlists genes and phenotypes observed on mutation of these genes but not correctly matched. Which one of the following combinations is correctly matched? (1) A - ii, B - i, C - iii, D - iv, (2) A - i, B - iii, C - iv, D - ii, (3) A - iv, B - ii, C - i, D - iii, (4) A - iii, B - iv, C - ii, D – i

Accurate Gene-Phenotype Matching for Maternal Effect Genes in Drosophila Anterior-Posterior Polarity

Which one of the following mRNAs is a BMP inhibitor and can rescue the dorsal structures of ventralized Xenopus embryo when injected into it? (1) beta-catenin (2) Noggin (3) Disheveled (4) Siamos 

Noggin: A Key BMP Inhibitor That Rescues Dorsal Structures in Ventralized Xenopus Embryos

Following statements are made regarding animal development: A. The cell is first specified towards a given fate, suggesting that it would develop into this cell type, even in a neutral environment. B. Holoblastic rotational cleavage is observed in tunicates. C. Infolding of sheet of cells is called ingression. D. Conditional specification can be observed in sea urchin embryos. Which one of the following options represents the combination of all correct statements? (1) A and B (2) B and C (3) A and D (4) C and D 

Understanding Cell Fate Specification and Cleavage Patterns in Animal Development

Which one of the following statements with respect to development in amphibians is correct? (1) Gastrulation begins with the invagination of bottle cells, followed by coordinated involution of the mesodermal precursors and the epiboly of the prospective ectoderm (2) The organizer induces the Nieuwkoop centre (3) The organizer is formed by the accumulation of B- catenin (4) In the absence of BMP inhibitors ectodermal cells form neural tube BMP 

Key Steps in Amphibian Gastrulation: Invagination, Involution, and Epiboly Explained

23. Which one of the following developmental processes in animals is more dependent on cellular movements? (1) pattern formation                                                (2) morphogenesis (3) cell differentiation                                       (4) growth 

Morphogenesis: The Crucial Role of Cellular Movements in Animal Development

Movement of epithelial sheet spreading as a unit to enclose deeper layers of the embryo is termed as (1) Epiboly (2) Emboly (3) Involution (4) Ingression 

 Epiboly: The Coordinated Spreading of Epithelial Sheets During Embryonic Development

Which one of the following is NOT a typical movement pattern observed during gastrulation? (1) Involution (2) Epiboly (3) Furrowing (4) Delamination 

Understanding Typical and Atypical Cell Movements During Gastrulation

The splitting or migration or one sheet of cells into two sheets as seen during hypoblast formation in bird embryogenesis is termed as (1) delamination (2) ingression (3) involution                                                 (4) invagination

Delamination: The Splitting of Cell Sheets During Hypoblast Formation in Bird Embryos

Inward movement of an expanding outer layer spreading over the internal surface during gastrulation is termed as (1) invagination (2) Ingression (3) involution (4) delamination 

 Understanding Involution: A Key Morphogenetic Movement During Gastrulation

Bones of vertebrates embryonic are derived from (1) ectoderm (2) epiderm (3) mesoderm (4) endoderm

Understanding the Embryonic Origin of Vertebrate Bones: The Role of the Mesoderm

14. Human chorionic gonadotropin (hCG) is known to facilitate attachment of blastocyst to uterus. In women with mutation in hCG gene, biologically inactive hCG was formed but implantation occurred. When hcG was immune-neutralized in the uterus of normal woman, implantation failed. This suggests that for implantation in humans: (1) biologically active circulating hCG is not required. (2) blastocyst can produce the required hCG, which helps locally in uterine attachment. (3) trophoblastic cells do not require hCG for the invasion of uterus. (4) extra-embryonic tissue is not responsible for the attachment of embryo to uterus 

Why Local hCG Production by the Blastocyst Is Essential for Human Embryo Implantation

Compaction during early embryonic development involves activation of actin filaments. Which one of the following inhibitors would prevent formation of the blastula from the morula? (1) An inhibitor that would block the action of Glin. (2) A specific inhibitor for stabilizing the function of Axin. (3) A specific inhibitor for GSK3B (4) An inhibitor which would block Smad4

The Essential Role of Actin Filaments and Cofilin1 in Embryonic Compaction and Blastula Formation

49. The HIPPO signaling pathway is important for cell proliferation. It is regulated by the protein kinases MST1/2 and LATS1/2 and the transcriptional activators YAP and TAZ. Accordingly, the following events may be observed within a cell. (A) Activation of TEADs by phosphorylated YAP/TAZ. (B) Activation of YAP/TAZ on phosphorylation by MST/LATS (C) Activation of TEADs by dephosphorylated YAP/TAZ (D) Inactivation of MST / LATS by repressors Which one of the following situations can support progression of cancer? (1) A and B (2) B and C (3) C and D (4) A and D 49. The HIPPO signaling pathway is important for cell proliferation. It is regulated by the protein kinases MST1/2 and LATS1/2 and the transcriptional activators YAP and TAZ. Accordingly, the following events may be observed within a cell. (A) Activation of TEADs by phosphorylated YAP/TAZ. (B) Activation of YAP/TAZ on phosphorylation by MST/LATS (C) Activation of TEADs by dephosphorylated YAP/TAZ (D) Inactivation of MST / LATS by repressors Which one of the following situations can support progression of cancer? (1) A and B (2) B and C (3) C and D (4) A and D

The Hippo Signaling Pathway and Its Role in Cancer Progression

The figure above represents a late zebrafish gastrula. The following concepts may be proposed during further development of the embryo. A. The concentration of FGF decreases from the yolk towards the epidermis, along with the increase of BMP activity from the dorsal to the ventral axis. B. Increase in FGF activity in the epidermis with concomitant decrease in BMP activity towards the ventral axis. C. Neural induction in zebrafish is independent of the organizer and depends on activation of BMP signaling. D. In comparison, both Xenopus and chick embryos require activation of FGF for neural induction to occur in addition to BMP inhibition. Which of the above statements are true? (1) A and C (2) B and C (3) A and D (4) C and D 

Morphogen Gradients and Neural Induction in Zebrafish and Comparison to Other Vertebrates

48. Hippo pathway is responsible for the trophoblast and inner cell mass (ICM) differentiation during mammalian development. Which one of the following is true for ICM formation? (1) The Tead4 transcription factor, when active, promotes transcription of Cdx2 gene leading to ICM formation. (2) If LATS kinase phosphorylates the YAP transcriptional coactivator, the phosphorylated form of YAP does not enter the nucleus and gets degraded which leads to ICM formation. (3) In the absence of functional LATS protein, the YAP transcriptional cofactor can bind to Tead4 to activate Cdx2 gene promoting ICM (4) Synthesis of Cdx2 upregulates Oct4 and Nanog leading to ICM formation. 48. Hippo pathway is responsible for the trophoblast and inner cell mass (ICM) differentiation during mammalian development. Which one of the following is true for ICM formation? (1) The Tead4 transcription factor, when active, promotes transcription of Cdx2 gene leading to ICM formation. (2) If LATS kinase phosphorylates the YAP transcriptional coactivator, the phosphorylated form of YAP does not enter the nucleus and gets degraded which leads to ICM formation. (3) In the absence of functional LATS protein, the YAP transcriptional cofactor can bind to Tead4 to activate Cdx2 gene promoting ICM (4) Synthesis of Cdx2 upregulates Oct4 and Nanog leading to ICM formation.

Role of the Hippo Signaling Pathway in Mammalian Inner Cell Mass Formation

11. Gradients of morphogens determine the future dorsal- ventral and anterior-posterior axes of the developing embryo in many organisms. How is the anterior- posterior axis developed in C. elegans? (1) Sperm entry leads to reorganization of the cytoskeleton and redistribution of naturally packed PAR proteins, which in turn determine the anterior- posterior axis. (2) After fertilization β-catenin gets localized into the nucleus of the future anterior cells. (3) The P-granules are localized in a way consistent with a role as a morphogenetic determinant and they act through translational regulation to initiate anterior-posterior axis. (4) The localization of the maternally expressed polypeptide SKN-1 is responsible for the

How Sperm Entry and PAR Proteins Establish the Anterior-Posterior Axis in C. elegans

47. The following statements are made about mammalian development: (A) Zygote is a totipotent stem cell. (B) The cells of inner cell mass are said to be pluripotent. (C) The three regulatory transcription factors, Oct4, Nanog and Sox2 help maintain pluripotency of the inner cell mass. (D) Cdx2 upregulates Oct4 and Nanog. Which one of the following options represents the correct combination of the statements? (1) A and B (2) B and C (3) C and D (4) A and D

Key Facts About Totipotency and Pluripotency in Mammalian Development

10. Given below are fate map of two organisms and the pattern by which embryos undergo cleavage. Which of the following is/are the right combination(s)? (1) B only                                            (2) B and A (3) A and C                                          (4) B and D

Matching Fate Maps and Cleavage Patterns: Finding the Right Combination in Embryology

46. The pluripotency of the inner cell mass in mammals is maintained by a core of three transcription factors namely, (1) Oct 4, Sox 2 and Nanog (2) Oct 4, Sox 2 and Cdx2 (3) Sox 2, Nanog and Cdx2 (4) Oct 4, Cdx2 and Nanog

The Core Transcription Factors Maintaining Pluripotency in Mammalian Inner Cell Mass

45. The following demonstrates proposed functions of different genes which determine the decision to become either trophoblast or inner cell mass (ICM) blastomere during early mammalian development: Based on the above figure, which one of the following assumptions is correct? (1) The interplay between Cdx2 and Oct4 can influence the formation of ICM (2) The ICM would form even if expression of Oct4 was inhibited. (3) YAP and TEAD4 are upstream components of Cdx2 and can be inhibited by Nanog. (4) The expression of Stat3 is optional for maintaining pluripotency of the ICM.

Role of Cdx2 and Oct4 in Early Mammalian Embryonic Cell Fate Decisions

44. The following are certain statements regarding stem cells: (A) All types of stem cells have the ability to give rise to a complete embryo. (B) Multipotent stem cells are those whose commitment is limited to a relatively small subset of all possible cell types. (C) Stem cell niches allow controlled self-renewal and also survival of the cells that leave the niche. (D) The pluripotency of the stem cells in an embryo is essentially maintained by Fgf8, Nanog and TGFβ. (E) Adult cells may be reprogrammed to gain pluripotency by modifying the following genes: Oct 3/4, sox2, c-Myc, Klf-4. Which one of the following combinations of statements is correct? (1) A,B and D (2) B and E (3) C and E (4) A, C and D

Stem Cell Niches: Key Regulators of Self-Renewal and Cell Survival

The table below lists cleavage pattern and names of species. Match the cleavage patterns with the species. (1) A- i; B- ii; C- iii; D- iv (2) A- ii; B- iv; C- i; D- iii (3) A- iv; B- i; C- iii; D- ii (4) A- iii; B- i; C- iv; D- ii 

 Matching Embryonic Cleavage Patterns with Representative Species: A Comprehensive Guide

43. The decision to become either a trophoblast or inner cell mass blastomere is one of the first decisions taken by any mammalian embryo. Below is a diagrammatic representation of the different cells formed during development from the morula with the help of different molecules. Identify the molecules 1-4, sequentially. (1) cdx 2, Oct 4, Nanog, Stat 3 (2) cdx 2, Nanog, Stat 3, Oct 4 (3) cdx 2, Nanog, Oct 4, Stat 3 (4) cdx 2, Oct 4, Stat 3, Nanog

Sequential Role of Key Molecules in Mammalian Embryo Cell Fate Decisions

8. Match the following cleavage patterns with the species in which they occur. (1) A-iv, B-iii, C-i, D-ii                                       (2) A-iii, B-i, C-iv, D-ii (3) A-ii, B-iii, C-i, D-iv                                       (4) A-ii, B-iv, C-iii, D-i

 A Detailed Guide to Embryonic Cleavage Patterns and Their Species Associations

42. Following statement were given regarding decisions taken during development of mammalian embryos (A) Pluripotency of inner cell mass is maintain by a core of three transcription factors, Oct 4, Sox 2 and nanog. (B) Prior to blastocyst formation each blastomere expresses both Cdx 2 and the Oct 4 transcription factors and appears to be capable of becoming either ICM or trophoblast. (C) Both ICM and trophoblast cells synthesize transcription factors Cdx 2. (D) Oct4 activates Cdx2 expression enabling some cells to become trophoblast and other cells to become ICM. Which of the above statement are true? (1) A and B (2) A and C (3) Band D (4) B and C

Key Transcription Factors Governing Mammalian Embryonic Development

The pattern of embryonic cleavage specific to a species is determined by two major parameters. (A) The amount and distribution of yolk protein within the cytoplasm. (B) The factors in the cytoplasm that influence the angle mitotic spindles and the timings of its formation. Which of the following statements are true? (1) Species having teloecithal egg follow a holoblastic cleavage. (2) Species having isolecithal egg follow a holoblastic cleavage. (3) Species having centrolecithal egg follow a holoblastic cleavage. (4) Species having isolecithal egg follow a meroblastic cleavage.

How Yolk Distribution and Cytoplasmic Factors Determine Embryonic Cleavage Patterns

41. The embryonic stem cells in mammals are derived from: (1) Blastocoel (2) Inner cell mass (3) Trophoectoderm (4) Trophoendoderm

Origin of Embryonic Stem Cells in Mammals: The Inner Cell Mass

40. The cells of inner cell mass of a blastocyst stage mammalian embryo are (1) totipotent (2) pluripotent (3) multipotent (4) unipotent

Potency of Inner Cell Mass Cells in Mammalian Blastocyst: Pluripotency Explained

Centrolecithal eggs show (1) superficial cleavage (2) displaced radial cleavage (3) bilateral cleavage (4) discoidal cleavage 

Understanding Cleavage in Centrolecithal Eggs: The Superficial Cleavage Pattern

39. Which statement is true about progenitor cells? (1) They are same as stem cells (2) They are totipotent cells (3) They can divide but do not remain undifferentiated (4) They cannot divide

Understanding Progenitor Cells: Characteristics and Differences from Stem Cells

5. Amphibian zygote will generally undergo (1) Holoblastic radial cleavage. (2) Holoblastic rotational cleavage. (3) meroblastic bilateral cleavage. (4) meroblastic rotational cleavage. 

Understanding Amphibian Embryonic Development: Holoblastic Radial Cleavage Explained

38. If skin cells are converted into induced stem cell then they can (1) Only duplicate (2) Only differentiate (3) Differentiate and duplicate (4) Differentiate and duplicate such that number of stem cells remains constant

The Capabilities of Induced Stem Cells Derived from Skin: Differentiation and Self-Renewal

What is the pattern of cleavage observed in mammals? (1) Radial (2) Spiral (3) Rotational (4) Bilateral

 The Rotational Cleavage Pattern in Mammalian Embryonic Development

Which kind of cleavage is shown in mammals? (1) Holoblastic rotational (2) Meroblastic rotational (3) Holobastic radial (4) Meroblastic radial 

Understanding Mammalian Embryonic Cleavage: The Holoblastic Rotational Pattern

If an embryo undergoes 13 cleavage divisions during embryogenesis, then the size of the embryo compared to zygote (1) increases 13 times. (2) increases only 6-7 times. (3) increases in an exponential fashion. (4) Remains almost the same.

Why Embryo Size Remains Constant During Early Cleavage Divisions

37. Which one of the following statements about stem cells is correct? (1) Stem cells cannot be maintained in culture since they required a distinct in vivo (2) During asymmetric stem cell division, only one of the daughter cells is retained as a stem cell. (3) Stem cell derived transit-amplifying cells are differentiated cells which retain the capacity to divide further (4) Hematopoietic stem cells (HSCs) are totipotent stem cells

Understanding Asymmetric Stem Cell Division: Balancing Self-Renewal and Differentiation

The two major properties of stem cells are (1) unlimited self-renewal and multi potent differentiation (2) limited passage and transformation (3) unidirectional differentiation and commitment (4) limited life span and senescence

Fundamental Properties of Stem Cells: Unlimited Self-Renewal and Multipotent Differentiation

35. Instructive and permissive interactions are two major modes of inductive interaction during development. The following compares some properties of cell lines and cord blood stem cells. Cell lines which are stored in liquid nitrogen, can be retrieved for experiments, where they behave as per their original self. Cord blood can also be retrieved from liquid nitrogen for procuring stem cells. Unlike cell lines, the stem cells can be additionally induced to undergo differentiation into desired lineage, which are very different from their original self. The behaviour of cell lines and stem cells is analogous to which of the interactions? (1) Both cell lines and stem cells show instructive interaction (2) Cell lines show instructive interaction whereas stem cells show permissive interaction (3) Cell lines show permissive interaction whereas stem cells show instructive interaction (4) Both types of cells show permissive instruction

Understanding Instructive and Permissive Interactions in Cell Development: Analogies with Cell Lines and Stem Cells

34. Following are certain statements regarding morphogen gradients and cell specification. (A) Morphogens are always transcription factors. (B) Morphogens can be paracrine factors that are produced in one group of cells and travel to another population of cells (C) When the concentration of a morphogen drops below a certain threshold cells stop differentiating and never get determined to another fate. (D) Morphogen gradients are involved in conditional specification. Which combination of the above statements is true? (1) A and B (2) B and D (3) C and D (4) A and C

Understanding Morphogen Gradients and Their Role in Cell Specification

Which is true for amount of yolk and cleavage in egg of amphibian? (1) Mesolecithal and holoblastic cleavage (2) Isolecithal and holoblastic cleavage (3) Mesolecithal and meroblastic cleavage (4) Microlecithal and meroblastic cleavage 

Understanding Amphibian Eggs: Mesolecithal Yolk Amount and Holoblastic Cleavage

Positional Information and Developmental Plasticity in Drosophila Leg Transplantation Experiments

Positional Information and Developmental Plasticity in Drosophila Leg Transplantation Experiments

32. Which of the following cannot be used for determination of tissue lineage of a given progenitor cell population in an animal? (1) Marking progenitor cells with vital dye. (2) Transplanting equivalent progenitor cells from immunologically distinct but related organism. (3) Marking progenitor cells by genomic recombination coupled with reporter gene expression. (4) Marking progenitor cells by reporter gene expression under the control of a promoter — enhancer element specific for the given progenitor population.

Methods for Determining Tissue Lineage: Advantages and Limitations

31. When prospective neuroectoderm from an early amphibian gastrula is transplanted in the prospective epidermal region of a recipient (early gastrula) embryo, the donor tissue will give rise to (1) neural tube. (2) epidermis. (3) neural tube and notochord. (4) neural tube and epidermis.

Fate of Prospective Neuroectoderm in Early Amphibian Gastrula Transplantation Experiments

Human sperms are allowed to fertilize ova having non- functional ovastacin. The following possibilities may be of significance in the fusion of these gametes: A. The sperms will not fertilize ova. B. The sperms will bind and penetrate the zonapellucida but will not be able to fuse with ovum membrane. C. ZP2 will not be clipped by cortical granule protease. D. CD9 protein of egg membrane microvilli will not be able to interact with sperm membrane proteins in the absence of ovastacin. E. Polyspermy may occur frequently. Which combination of statements represent the outcome of the above event? (1) A and B (2) C and E (3) C and D (4) B and C

How Non-Functional Ovastacin Impacts Polyspermy Prevention in Human Fertilization

30. Which of the inferences (A-D) given below would you draw from the following tissue transplantation experiments performed with the early and late gastrula stages of the newt? (A) Cells of early newt gastrula exhibit conditional development. (B) Cells of early newt gastrula exhibit autonomous development (C) Cells of late newt gastrula exhibit conditional development. (D) Cells of late gastrula exhibit autonomous development. The correct inferences are: (1) (A) and (D) (2) (B) and (C) (3) (A) only (4) (D) only

Developmental Specification in Newt Gastrula: Insights from Tissue Transplantation Experiments

29. When the prospective neurons from an early gastrula of a frog were transplanted into the prospective epidermis region, the donor cells differentiated into epidermis. However, when a similar experiment was done with the late gastrula of frog, the prospective neurons developed into neurons only. These observations could possibly be explained by the following phenomena. (A) The early gastrula show conditional development whereas the late gastrula shows autonomous development. (B) The early gastrula show autonomous development whereas the late gastrula shows conditional development. (C) The prospective neurons from the early gastrula are only specified whereas those from the late gastrula are determined. (D) The prospective neurons from the early gastrula are determined whereas those from the late gastrula are specified. Which of the conclusions drawn above are correct? (1) A and B (2) A and C (3) A and D (4) B and C

Differentiation and Fate Determination in Frog Gastrula Neurons: Conditional vs Autonomous Specification

28. When 8-cell embryo of tunicates is separated into 4 blastomere pairs and allowed to grow independently in culture medium, then each blastomere pair can form most the cell types; however, cells for nervous system are not developed. The following statements are formed from the above observations: (A) Nervous system development demonstrated autonomous specification. (B) The other tissue types are formed due to conditional specification. (C) All the tissue types, except nervous tissues that developed demonstrated autonomous specification. (D) Nervous system development demonstrated conditional specification. The correct combination of statements that explains the above result is: (1) A and B (2) B and C (3) C and D (4) A and D

Specification of Tissue Lineages in Tunicate Embryos: Autonomous and Conditional Modes

27. C. elegans embryo uses both autonomous and conditional modes of specification. The following statement are about specification of cell lineages: (A) The signals from the P1 blastomere instructs the EMS cell for its further development. (B) In the absence of the instructive signal, the EMS cell will divide into two MS cells. (C) In the absence of the POP-1 signal, the prospective MS cell can take up the E fate. (D) The MOM-2 protein from the blastomere neighbouring the EMS cell instructs the dividing EMS blastomere to take up MS fate. Which one of the following options represent both correct statements? (1) A and B (2) B and C (3) C and D (4) A and D

Intercellular Signaling and Fate Specification of the EMS Blastomere in Caenorhabditis elegans Embryos

26. The following figure represents the interaction between different blastomeres in a 4-cell stage of C. elegans embryo: The following statements were made regarding the above: A. The fate of EMS blastomere is autonomously specified. B. The default fate of EMS blastomere is MS cell lineage. C. Conditional specification can be observed in the development of E cell lineage. D. Assuming that a receptor needs to be activated for E fate, a C. elegans embryo where the receptor is constitutively active, is likely to develop cells of E fate only, in all three of the above cases. Which one of the following options represents the combination of all correct statements? (1) A and C only (2) B and C only (3) A, B and C (4) B, C and D

Conditional Specification and Gene Regulation in the EMS Blastomere of Caenorhabditis elegans Embryos

25. C. elegans embryo uses both autonomous and conditional modes of specification. Conditional specification at the 4-cell stage can be seen in the development of the endoderm cell lineage and also in the establishment of dorsal-ventral axis. Following are few statements regarding this: (A) If the P2 cell is removed at the early 4-cell stage, the EMS cell will divide into two MS cells and no endoderm will be made. (B) In pop-1 deficient embryos, both EMS daughter cells become E cells. (C) When the position of ABa and ABp was reversed, their fates get reversed and no normal embryo forms. (D) In embryos whose mother have mutant glp-1, Abp is transformed into ABa cell. Which of the above statements are true? (1) A, B and D (2) A, B and C (3) B, C and D (4) A, C and D

Conditional Specification and Cell Fate in the 4-Cell Stage of Caenorhabditis elegans Embryos

A two-celled embryo is made of blastomeres A and B. If the two blastomeres are experimentally separated, the 'A' blastomere generates all the cells it would normally make. However, the 'B' blastomere in isolation makes only a small fraction of cells it would normally make. Based on the above observations only, which one of the following conclusions is correct? (1) 'A' blastomeres is autonomously specified while 'B' blastomere is conditionally specified (2) 'A' blastomeres is conditionally specified while 'B' blastomere is autonomously specified (3) Descendants of 'A' blastomeres are autonomously specified (4) Descendants of 'B' blastomeres can either be autonomously specified or conditionally specified.

Understanding Autonomous and Conditional Specification in Early Caenorhabditis elegans Embryos

23. The zygote of C. elegans exhibits rotational cleavage. When the first two blastomeres formed (P1 and AB) are experimentally separated, the following outcomes may be possible: (A) The P1 cell in isolation generates all the cells it would normally make, showing autonomous specification. (B) The P1 cell in isolation generates all the cells it would normally make, showing conditional specification. (C) The AB cell in isolation generates a small fraction of cell types it would normally make, showing conditional specification. (D) The AB cell in isolation generates a small fraction of cell types it would normally make, showing autonomous specification. Which one of the above combination of statements is true? (1) A and C (2) B and C (3) B and D (4) A and D

Specification Patterns of AB and P1 Blastomeres in Early Caenorhabditis elegans Embryos

At the 2-celled stage of Caenorabditis elegans development the blastomeres were experimentally separated and allowed to proceed in development. One of the blastomere (P1) developed generating all types of cells it would normally make while the other blastomere (AB) made only a fraction of the cell types it would normally make. The following conclusion could be drawn: (A) The determination of both P1 and AB was autonomous. (B) The determination of both P1 and AB was conditional. (C) The determination of P1 was autonomous and AB was conditional. (D) Both asymmetric division and cell-cell interactions specify cell fate in early development. Which of the above combinations is correct? (1) A and C (2) B and D (3) A and D                 (4) C and D

Cell Fate Determination in Caenorhabditis elegans: Autonomous and Conditional Specification of Blastomeres

21. During early cleavage of Caenorabditis elegans embryos, each asymmetrical division produces one founder cell which produces differentiated descendants and one stem cell. The very first cell division produces one anterior founder cell, namely AB and one posterior stem cell, namely P1. When these blastomeres are experimentally separated and allowed to proceed further with development, one could get the following possible outcomes: (1) P1 cell would develop autonomously while the AB would show conditional development. (2) P1 cells would show conditional development while AB would show autonomous development. (3) Both would show autonomous specification and result in mosaic development. (4) Both would show conditional specification and result in regulative development.

Autonomous and Conditional Specification in Early Caenorhabditis elegans Embryo Development

20. If the blastomeres of a 4 celled sea urchin embryo are isolated each blastomere can form a pluteus larvae. This is example of (1) Autonomous specification (2) Conditional specification (3) Determination (4) Mosaic development

Example of Conditional Specification in Sea Urchin Embryo Development

19. The fate of a cell or a tissue is specified when it is capable of differentiating autonomously on being placed in a neutral environment with respect to the developmental pathway. An embryo will show development pattern based on its type of specification: Based on the above facts it can be said that potency of a cell is: (A) Equal to its normal fate in regulative development (B) Greater than its normal fate in regulative development (C) Equal to its normal fate in mosaic development (D) Greater than its normal fate in mosaic development Which of the above statements are true? (1) (B) and (C) (2) (A) and (D) (3) (A) and (C) (4) (B) and (D)

Understanding Cell Potency and Fate Specification in Embryonic Development

Given are certain facts which define 'determination' of a developing embryo. A. Cells have made a commitment to a differentiation program. B. A phase where specific biochemical actions occur in embryonic cells. C. The cell cannot respond to differentiation signals. D. A phase where inductive signals trigger cell differentiation. Which of the above statements best define determination? (1) B and D (2) A and C (3) Only A                                                             (4) Only B

Defining Determination in Embryonic Development: Key Characteristics and Misconceptions

17. During development, if a cell has committed to a particular fate, it is said to be (1) pluripotent (2) totipotent (3) determined (4) differentiated

Cell Commitment in Development: Understanding Determination in Embryogenesis

16. In a transplantation experiment, the area of presumptive ectoderm from an early frog gastrula was transplanted to a region of the newt gastrula destined to become parts of the mouth. The resulting salamander larvae had frog like mouth parts (frog tadpole suckers) instead of balancers as observed during development of wild type newt embryo. This is an example of (1) Determination (2) Genetic specificity of interaction (3) Regional specificity of interaction (4) Autonomous specification

Genetic Specificity of Interaction Demonstrated in Cross-Species Embryonic Transplantation

15. In chick, development of wing feather, thigh feather and claws depends on epithelial specificity conferred by induction from mesenchymal components from different sources of the dermins. This may be attributed to? (1) Autocrine interaction (2) Regional specificity of induction (3) Receptor activation by hormones (4) Inactivation of genetic interactions

Regional Specificity of Induction in Chick Feather Development

14. Induction is an extrinsic process that depends on the position of a cell in the embryo. It is a process whereby one cell or group of cells can influence the developmental fate of another, and is a common strategy to control differentiation and pattern formation in development. The following statements were made regarding induction in a developing embryo. A. The inductive signal can be a protein secreted from the inducing cells that binds to receptors of a responding cell. B. Response to inductive signals depends on competence of the inducing cell. C. Instructive induction occurs when the responding cell is already committed to a certain fate. D. Lateral inhibition is an induction that results in differentiation of individual cells in a regularly spaced pattern. Which one of the following combination of statements is correct? (1) A and C (2) B and D (3) A and D (4) B and C

Key Concepts of Induction in Embryonic Development: Understanding Signal and Cellular Responses

Which one of the following best describes the ability of the cells to respond to a specific inducing signal? (1) Potency (2) Equivalence (3) Competence (4) Specification

Competence in Developmental Biology: Cells’ Ability to Respond to Inductive Signals

Learn about the concept of competence—the ability of cells to respond to specific inductive signals—and its critical role in embryonic development and cell communication.

Understanding Competence in Cell-to-Cell Communication During Development

11. Certain proteins or mRNAs that are regionally localized within the unfertilized egg and regulate development are called (1) gene regulators. (2) morphometric determinants . (3) cytoplasmic determinants. (4) mosaic forming factors.

Understanding Cytoplasmic Determinants in Embryonic Development

10. Following statements are being made regarding specification determination during animal development: A. During the course of commitment, the cell may not appear different from its nearest or most distant neighbors in the embryo and show no visible signs of differentiation; but its developmental fate is restricted. B. At the stage of specification, cell commitment is not labile. C. A cell or tissue is determined when it is capable of differentiating autonomously even when placed into another region of the embryo, or a cluster of differently specified cells in a petri- dish D. Cytoskeletal arrangements maintain positioning of nuclei in the syncytium, which enables specification of these nuclei by opposing morphogen gradients namely Bicoid and Caudal in Drosophila E. Capacity for "mosaic" development allows cells to acquire different functions as a result of interactions with neighbouring cells. Which of the above statements are correct? (1) A B and C (2) B, C and D (3) C, D and E (4) A, C and D

Understanding Specification and Determination in Animal Development

9. With respect to development of any organism, "conditional specification" would result in which type of development? (1) Regulative (2) Mosaic (3) Syncytial (4) Definitive

Conditional Specification and Its Role in Regulative Development

8. With respect to development of any organism, "autonomous specification" would result in which type of development? (1) Regulative. (2) Syncytial. (3) Mosaic. (4) Definitive.

Autonomous Specification and Its Role in Mosaic Development

7. If you remove a set of cells from an early embryo, you observe that the adult organism lacks the structure that would have been produced from those cells. Therefore, the organism seems to have undergone (1) autonomous specification. (2) conditional specification. (3) morphogenic specification. (4) syncytial specification.

Understanding Embryonic Specification: Autonomous vs Conditional and Morphogenic Specification

The biggest disadvantage of sexual reproduction against the asexual reproduction is (1) Only half of genetic material is passed to offspring from each parent (2) Lot of energy and time is consumed in locating mate (3) It brings unnecessary variations (4) After fertilization in many cases zygote fails to develop

Biggest Disadvantage of Sexual Reproduction Compared to Asexual Reproduction

6. The ability of cells to achieve their respective fates by interacting with other cells is known as (1) autonomous specification (2) conditional specification (3) induction (4) competence

Understanding Cell Fate Determination: The Role of Induction and Cell Interactions

5. In regulative development, the prospective potency of cells (1) Equal to prospective fate (2) More than prospective fate (3) Lesser than prospective fate (4) Not determined

Understanding Prospective Potency and Fate in Regulative Development

4. In an early embryonic transplantation experiment prospective skin cells were transferred near future muscle cell but then also it differentiates into skin cell. The cell would be termed (1) Determined (2) Committed (3) Totipotent (4) Differentiated

Understanding Cell Fate: Determined, Committed, Totipotent, or Differentiated?

3. Mosaic developmental pattern is always (1) Autonomous (2) Non autonomous (3) Conditional (4) Regulative

Mosaic Developmental Pattern Explained: Autonomous or Conditional?

2. Homeotic genes are responsible for (1) Maintaining gaps in segments (2) Provide gradient for anterior posterior axis of embryo (3) Codes secretory morphogens (4) Formation of organ at defined locations

Understanding the Role of Homeotic Genes in Development and Organ Formation

Sperms are morphologically fit but are unable to actively swim (hyper activation) due to lack of (1) Spermatogenesis (2) Spermiogenesis (3) Prostrate glands (4) Capacitation 

Why Morphologically Normal Sperms Fail to Exhibit Hyperactivation: The Role of Capacitation

1. Homeotic genes are responsible for (1) Development of anatomical structures (2) Homeostasis (3) Cell cycle regulation (4) Adaptation to stress

Homeotic Genes: Master Regulators of Developmental Anatomy

60. Which one of the following plant homeotic genes does NOT encode MADS- domain transcription factor involved in floral organ specification? (1) AP2                                                         (2) AP1 (3) AP3/P1                                                     (4) AG 
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development

APETALA2: A Non-MADS-Domain Transcription Factor in Floral Organ Specification

60. Which one of the following plant homeotic genes does NOT encode MADS- domain transcription factor involved in floral organ specification? (1) AP2                                                         (2) AP1 (3) AP3/P1                                                     (4) AG   […]

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