21. Capacitation of sperms in humans (1) occurs during copulation. (2) occurs after the acrosome reaction. (3) takes place in the ampulla of the oviduct. (4) takes place in the […]
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CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Conditional Specification and Cell Fate in the 4-Cell Stage of Caenorhabditis elegans Embryos
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 […]
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Understanding Autonomous and Conditional Specification in Early 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 […]
CSIR NET Life Science Previous Year Questions and Solution on Development Biology
How Progesterone Initiates Meiotic Resumption in Amphibian Oocytes
Amphibian oocytes remain for years in the diplotene stage of meiotic prophase. Resumption of meiosis is initiated by (1) gonodatropic hormone. (2) growth hormone. (3) oestrogen. (4) progesterone. Introduction […]
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Specification Patterns of AB and P1 Blastomeres in Early Caenorhabditis elegans Embryos
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 […]
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Cell Fate Determination in Caenorhabditis elegans: Autonomous and Conditional Specification of Blastomeres
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 […]
CSIR NET Life Science Previous Year Questions and Solution on Development Biology
Stepwise Process of Fertilization in Amphibians: From Sperm Chemoattraction to Sperm Entry
19. During fertilization in amphibians, the fusion of egg and sperm plasma is preceeded by (A) release of enzymatic contents from the acrosomal vesicle through exocytosis (B) binding and interaction […]
CSIR NET Life Science Previous Year Questions and Solution on applied ecology
The Crucial Role of Bindin and EBR1 in Sea Urchin Fertilization: Molecular Mechanisms and Egg Membrane Dynamics
18. Fertilization in sea urchin involves interaction of sperm Bindin with its receptor EBR1, a 350 kDa glycoprotein on the egg vitelline membrane. The plot given below shows the status […]
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Autonomous and Conditional Specification in Early Caenorhabditis elegans Embryo Development
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 […]
CSIR NET Life Science Previous Year Questions and Solution on Basic Concepts of Development
Example of Conditional Specification in Sea Urchin Embryo Development
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) […]
