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 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

23.

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

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  

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 is NOT a physiological characteristic of early successional plants?

• High respiration rate  

• Inhibition by far red light 

• High transpiration rate 

• Low photosynthetic rate  

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   

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  

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