25. During glycolysis in plants, alanine and related 10 acids are directly produced from which one of i'he following precursors? (1) 3-Phosphoglycerate (2) Phosphoenolpyruvate (3) Pyruvate (4) Acetyl-CoA

Pyruvate as the Direct Precursor of Alanine and Related Amino Acids in Plant Glycolysis

24. Glycolysis and citric acid cycle contribute precursors to many biosynthesis pathway in plants. column X lists names of the precursors and column Y lists the product synthesized. Column X Column Y A. Hexose phosphate (i) Aspartate B. Pyruvate (ii) Alanine C. Pentose phosphate (iii) Cellulose D. Oxaloacetate (iv) Nucleotides Which one of the following options represents the correct match between column X and Y? (1) A-ii, B-iii, C-i and D-iv (2) A-iii, B-ii, C-iv and D-i (3) A-iv, B-i, C-iii and D-ii (4) A-i, B-ii, C-iii and D-iv

Key Biosynthetic Precursors from Glycolysis and Citric Acid Cycle in Plants

23. First committed precursor in biosynthesis of chlorophyll is: (1) delta-aminolevulinic acid (2) Porphobilinogen (3) Protoporphyrin IX (4) coproporphyrinogen III

First Committed Precursor in Chlorophyll Biosynthesis

22. Following are certain statements regarding respiratory metabolism on plants: A. Respiratory quotient during partial breakdown of carbohydrate (alcoholic fermentation) will be infinity. B. Respiratory quotient indirectly provides inforrnation about (i) nature of the substrate used for respiration and (ii) the relative rate of competing respiratory processes. C. Breakdown of organic adds in mature fruit will exhibit a respiratory quotient value of more than one since organic acids are relatively oxygen-rich compared to other common substrates. D. Anabolic metabolism can influence respiratory quotient by removing reduction equivalents for respiration leading to decrease in oxygen uptake. Which one of the following combination of the above statement is correct? (1) Only A (2) Only B and C (3) Only D (4) A,B,C and D

Respiratory Quotient in Plant Metabolism

21. Which of the following staternents with respect to altenate oxidase activity on cyanide- resistant respiration in plants. is not correct? (1) Alternate oxidase accepts electrons directly from cytochrorre C (2) Some plants exhibit thermogenesis during inflorescence development. (3) Transcription of alternate oxidase gene is often induced by various abiotic stresses. (4) When electrons pass to alternate oxidase, two sites of proton pumping are bypassed.

Alternative Oxidase in Cyanide-Resistant Respiration in Plants

20. According to the current model of alternative oxidase regulation, the following factors cause induction of atternative oxidase (A) significant increase on the ubiquitin pool in the cytosol. (B) Presence of a-keto acids (like pyruvate and glyoxylate. (C) cold stress. (D) increase in cytosolic ATP concentration. Which one of the following combinations of above statements is true? (1) (A) and (D) (2) (B) and (C) (3) (A) and (B) (4) (A) and (C)

Factors Inducing Alternative Oxidase Expression in Plants

19. Following are certain statements with regard to plant respiration: A. Metabolism of glucose into pyruvate through glycolysis generates NADH and not NADPH. B. Metabolism of glucose through oxidative pentose phosphate cycle does not produce NADPH. C. Cyanide forms a complex with haem iron of cytochromeoxidase leading to prevention of change in valency, which in turn stops electron transport in the respiratory chain. D. Alternative oxidase is insensitive to cyanide and has higher km than that of cytochrome oxidase. Which one of the following combination is correct? (1) A,B and C (2) B,C and D (3) B and D (4) A,C and D

Key Concepts about Plant Respiration

18. The chemical salicyl hyrooxamic add (SHAM) inhibits (1) Cytochrome oxidase (2) Alternate oxidase (3) ATP synthase (4) NADH-dehydrogenase

Salicylhydroxamic Acid (SHAM) Inhibition of Alternative Oxidase in Plant Respiration

17. The alternative pathway of respiration can be inhibited by (1) Cyanide (2) SHAM (3) Arachidonic add (4) Ampicillin

SHAM as Inhibitor of Alternative Respiratory Pathway in Plants

16. In arum lily, the temperature of inflorescence rise around 10°C as compare to plant during blooming. The natural trigger for heat production in the inflorescences of Saummatum guttatum (voodoo lily), a thermogenic plant, and identified it as salicylic add which allow expression of (1) NADH Dehydrogenase (2) Cytochrome oxidase (3) Alternate oxidase (4) Uncoupling protein

Salicylic Acid Induced Heat Production in Thermogenic Plants

15. Following statements are related to oxidative phosphorylation A. Redox reactions of electron transport chain coupled with ATP synthesis are collectively called oxidative phosphorylation. B.Three major processes: glycolysis, oxidative pentose phosphate pathway and citric acid cycle are related to oxidative phosphorylation. C.Electron transport proteins are bound to outer of the two mitochondria! membranes. D.In the electron transport chain electrons are transferred to oxygen from NADH. Which one of the following combinations of above statements is correct? (1) A and D (2) B and C (3) C and D (4) A and C

Key Concepts of Oxidative Phosphorylation and ETC

14. The oxidation pentose phosphate pathway provides the reducing equivalents for nitrite reduction in plastids (leucoplasts) of non-green tissues. Which one of the following statements would be correct for the above mentioned pathway? (1) Glutamate synthesized from NH4+ is translocated from cytosol to leucoplast (2) alpha-ketoglutarate is translocated from cytosol to leucoplast. (3) Glucose-6-phosphate is translocated and moves from leucoplast to cytosol. (4) Triose Phosphate is translocated from cytosol to leucoplast.

Alpha-Ketoglutarate Transport

13. Which one of the following statements is INCORRECT about the role of oxidative pentose phosphate pathway in plant metabolism? (1) Generation of NADPH required to drive biosynthetic reactions. (2) Production of pentose phosphate for the synthesis of nucleic acids. (3) Formation of erythrose 4-phosphate for biosynthesis of aromatic amino acids. (4) Production of NADH to generate ATP

Role of Oxidative Pentose Phosphate Pathway in Plant Metabolism

12. Pyruvate dehydrogenase complex has sophisticated regulatory mechanisms including reversible phosphorylation. Various metabolites are also able to modulate the dehydrogenase complex. Which one of the following statements is NOT correct? (1) Pyruvate stimulates the kinase. (2) Pyruvate inhibits the kinase. (3) Ammonia stimulates the kinase. (4) Ammonia inhibits pyruvate oxidation.

Regulation of Pyruvate Dehydrogenase Complex by Metabolites and Phosphorylation

11. During episodes of anoxia in plants, pyruvate produced in glycolysis is initially fermented to lactate. During later stage, there is an increase in the fermentation to ethanol and decrease in the fermentation to lactate, a phenomena which helps plants survive anoxia. Which of the following statements is correct about this change of fermentation flux from lactate towards ethanol? (1) The cytosolic pH increases, thus activating both lactate dehydrogenase and pyruvate decarboxylase ativity (2) cytosolic pH increases, thus inhibiting lactate The cytosolic pH increases, thus inhibiting lactate dehydrogenase activity and activating pyruvate decarboxylase activity. (3) The cytosolic pH decreases, thus activating both lactate dehydrogenase and pyruvate decarboxylase activity. (4) The cytosolic pH decreases, thus inhibiting lactate dehydrogenase and activating pyruvate decarboxylase activity

Shift from Lactate to Ethanol Fermentation in Plants Under Anoxia

10. Pyrurate dehydrogenase is subject to feedback inhibition by its products in glycolysis. Some of the chemical compounds which might be involved in the process, are listed below: A. NADH B. FADH C. Acetyl-CoA D. Acetaldehyde Which one of the following combinations of above chemical compounds is involved in feedback inhibition of pyruvate dehydrogenase? (1) A and B (2) B and C (3) C and D (4) A and C

Feedback Inhibition of Pyruvate Dehydrogenase

9. Ribulose bisphosphate carboxylase (Rubisco) catalyzes both carboxylation and oxygenation of ribulose-1,5bisphosphate. The latter reaction initiates a physiological process known as 'photorespiration'. The following are certain statements on photorespiration: (A) The active sites on Rubisco for carboxylation and oxygenation are different. (B) One of the steps in photorespiration is conversion of glycine to serine. (C) 50% of carbon lost in chloroplast due to oxygenation is recovered through photorespiration. (D) The pathway of photo respiration involves chloroplast, peroxisorne and mitochondria. Which one of the following combinations of above statements is correct? (1) A and C (2) A and D (3) B and D (4) C and D

Organelles Involved in Photorespiration Process

8. Following are certain statements regarding photorespiration pathway in plants: (A) The first two-carbon (2C) compound synthesized by the action of Rubisco in the chloroplast is glycolate (B) Glycolate exits the chloroplast and enters peroxisomes. (C) Glycolate that is synthesized during C2 cycle ente the chloroplast from mitochondria. (D)Glycine is transported from peroxisornes mitochondria. Which one of the following combinations is INCORRECT? (1) A and B only (2) A and C only (3) B,C and D (4) A, C and D

Photorespiration Pathway and Metabolite Transport Between Organelles

7. Which of the following statements are associated with the process of photorespiration in plants? (A) Photorespiration takes place in mainly C3 plants. (B) Photorespiration takes place in mainly C4 plants. (C) Photorespiration takes place in both C3 and C4 plants. (D) Glycolate is oxidized to glyoxylate in the peroxisome. (E) Glycolate is oxidized to glyoxylate in the mitochondira. (1) (A) and (D) (2) (C) and (D) (3) (B) and (E) (4) (C) and (E)

Photorespiration in C3 and C4 Plants

6. In which one of the following subcellular organelles in serine synthesized during the oxidative photosynthetic carbon (C2) pathway? (1) Chloroplast (2) Mitochondria (3) Peroxisome (4) Rough endoplasmic reticulum

Serine Synthesis Organelle in C2 Oxidative Photosynthetic Cycle

5. During the operation of C2 oxidative photosynthetic cycle, which of the following metabolites is transported from chloroplast to peroxisome? (1) Glycerate (2) Serine (3) Glycine (4) Glycolate

Glycolate Transport from Chloroplast to Peroxisome in Photorespiration

4. Which one of the following metabolites moves from rnitochondria to peroxisome during the operation of the C2 oxidative photosynthetic cycle? (1) Glycerate (2) Glycolate (3) Glycine (4) Serine

Glycine Transport

3. During photorespiration which organelle is involved in conversion of glycolate into glyoxylate? (1) Mitochondria (2) Peroxisomes (3) Chloroplast (4) Nucleus

Site of Glycolate to Glyoxylate Conversion in Photorespiration

2. The organelle of C3 plants, where glyoxylate is formed is (1) Chloroplast (2) Peroxisome (3) Mitochondria (4) Cytosol

Organelle Responsible for Glyoxylate Formation in C3 Plants

1. Direct oxidation of photo respiratory peroxides in plants is carried out by- (1) Superoxide Dismutase (2) Glutathione Synthase (3) Catalase (4) Glutathione reductase

Direct oxidation of photo respiratory peroxides in plants

CSIR NET Life Science Previous Year Questions and Solution PHOTORESPIRATION AND RESPIRATION

First Committed Precursor in Chlorophyll Biosynthesis

23. First committed precursor in biosynthesis of chlorophyll is: (1) delta-aminolevulinic acid                 (2)  Porphobilinogen (3) Protoporphyrin IX                         (4) coproporphyrinogen III The first committed precursor in the biosynthesis of chlorophyll is delta-aminolevulinic […]

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