CSIR UGC NET JRF Life Sciences (Unit 6 - Plant System Physiology) Previous Questions

1. Phenylalanine, a precursor of most of the phenolics in higher plants is a product of which one of the following pathways? (CSIR Life Science 2015 Dec)

 1. Shikimic acid pathway

 2. Malonic acid pathway

 3. Mevalonic acid pathway

 4. Methylerythritol pathway

Ans:  1. Shikimic acid pathway

2. For which one of the following physiological studies 12CO2 and 13CO2 are used? (CSIR Life Science 2015 Dec)

1. Estimate the rate of photosynthesis

2. Determine rate of photorespiration

3. The ratio of C4 and CAM pathways of CO2 fixation

4. The ratio of C3 and C4 pathways of CO2 fixation

Ans: 4. The ratio of C3 and C4 pathways of CO2 fixation

3. Gibberellic acid (GA) controls seed germination by directing breakdown of the stored starch. In which one of the following tissues of the barley seed, α- amylase gene is induced in response to GA? (CSIR Life Science 2015 Dec)

1. Endosperm

2. Coleoptile

3. Aleurone layer

4. Embryo

Ans: 3. Aleurone layer

4. The photosynthetic assimilation of atmospheric CO2 by leaves yield sucrose and starch as end products of two gluconeogenic pathways that are physically separated. Which one of the following combination of cell organelles are involved in such physical separation of the process? (CSIR Life Science 2015 Dec)

1. Sucrose in cytosol and starch in mitochondria.

2. Sucrose in chloroplasts and starch in cytosol.

3. Sucrose in mitochondria and starch in cytosol.

4. Sucrose in cytosol and starch in chloroplasts.

Ans:  4. Sucrose in cytosol and starch in chloroplasts.

5. Which one of the following best describes the symplast pathway of water flow from the epidermis to endodermis in a plant root? (CSIR Life Science 2016 June)

1. Water moves through cell walls and extracellular spaces without crossing any membrane

2. Water travels across the root cortex via the plasmodesmata

3. Water crosses the plasma membrane of each cell in its path twice, once on entering and once on exiting

4. Transport across the tonoplast

Ans: 2. Water travels across the root cortex via the plasmodesmata

6. The herbicide, dichlorophenyldimethylurea, is an inhibitor of (CSIR Life Science 2016 June)

1. shikimate pathway for biosynthesis of aromatic amino acids.

2. electron transport from P680 to P700.

3. branched chain amino acid pathway.

4. electron transport from P700 to ferredoxin.

Ans: 2. electron transport from P680 to P700.

7. Which one of the following compounds is NOT a part of alkaloid class of secondary metabolites? (CSIR Life Science, 2016 June)

1. Lignin

2. Indole

3. Tropane

4. Pyrrolidine

Ans: 1. Lignin

8. Which one of the following plant derived signalling molecules induces hyphal branching of arbuscular mycorrhizal fungi, a phenomenon that is observed at the initial stages of colonization by these fungi? (CSIR Life Science, 2016 June)

1. Salicylic acid

2. Abscisic acid

3. Strigolactones

4. Systemin

Ans:  3. Strigolactones