Atmospheric CO2 contains the naturally occurring stable carbon isotope 12C and 13C in the proportion of 98.9% and 1.1% respectively. Following are some of the statements regarding CO2 assimilation
A. Both C3 and C4 plants assimilates less 13CO2 than 12CO2
B. Both C3 and C4 plants assimilates less 12CO2 than 13CO2
C. C3 plants assimilate lesser 13CO2 than 12CO2 as compared to C4 plants.
D. C4 plants assimilate lesser 12CO2 than 12CO2 as compared to C3 plants
Which one of the following combinations of above statements is true?
A and B
A and C
C and D
A and D
D.
A and D
Both C3 and C4 plants assimilates less 13CO2 than 12CO2 and C4 plants assimilate lesser 12CO2 than 12CO2 as compared to C3 plants.
Which of the following is NOT a physiological characteristic of early successional plants?
High respiration rate
Inhibition by far red light
High transpiration rate
Low photosynthetic rate
Following are some statements for synthesis of secondary metabolites in plants.
A. Terpenes are synthesized by shikimic acid pathway and mevalonic acid pathway.
B. Alkaloids are nitrogen containing compounds and are synthesized by shikimic acid pathway.
C. Phenolic compounds are synthesized by shikimic acid pathway and mevalonic acid pathway.
D. Both alkaloids and terpenes are synthesized by mevalonic acid pathway and MEP pathway.
Which of the following combinations of the above statements are true?
A and D
A and C
B and C
B and C
Mutations in CONSTANS (CO) of Arabidopsis thaliana results in late flowering phenotype. Transcript levels of CO were determined in long day and short day seedlings. Which of the following would likely represent the transcript profile of CO?
| Long -day seedlings | Short - day seedlings |
| Long- day seedlings | Short- day seedlings |
| Long-day seedlings | Shgsort-day seedlin |
| Long-day seedlings | Short-dsay seedling |
Following are some statements regarding plant growth hormones.
A. Ethylene regulates abscission.
B. Gibberlins do not play any role in flowering.
C. Auxin and cytokinin promote cell division.
D. Over expression of cytokinin oxidase would promote root growth.
E. ABA inhibits root growth and promotes shoot growth at low water potential.
F. ABA promotes leaf senescenceindependent of ethylene.
Which one of the following combination of above statements is correct?
A, C and F
B, C and D
D, E and F
B, D and E
Following are some of the statements regarding the effect of CO2 concentration on photosynthesis in plants.
A. With elevated CO2 levels, C3 plants are much more responsive than C4 plants under well watered conditions.
B. In C3 plants, increasing intracellular CO2 partial pressure can stimulate photosynthesis only over a narrow range.
C. In C4 plants, CO2 compensation point is nearly zero.
Which one of the following combination of above statements is correct?
A and B
B and C
A and C
Only C
The quantum yield of photosynthetic carbon fixation in a C3 plant and C4 plant is tudied, as a function of leaf temperature. Following are some statements based on this study.
A. At lower temperature the quantum yield of C3 plant is lower than C4
B. In C4 plant quantum yield does not show a temperature dependence.
C. Since, the photorespiration is low in C4 plants because of CO2 concentrating mechanism, quantum yield is not affected.
D. At higher temperature the quantum yield of C3 plant is lower than C4
Which one of the following combination above statements is correct?
A, B and D
B, C and D
A, B and C
A, C and D
Chloroplast distribution in a photosynthesizing cell is governed by blue light sensing phototropin 2 (PHOT2). When the cells are irradiated with high intensity blue light, the clorplasts
Move to the side walls
Aggregate in the middle of the cell
Are sparsely distributed
Aggregate in small clusters
Which of the following features is NOT shown by glyphosate, a broad spectrum herbicide?
Little residual soil activity
Ready translocation in phloem
Inhibition of a chloroplast enzyme catalyzing the synthesis of aromatic amino acids
Inhibition of early steps in the biosynthesis of branched chain amino acids
During development of embryos in plants, PIN proteins are involved in
Establishment of auxin gradients
Regulation of gene expression
Induction of programmed cell death
Induction of cell division
