Some given  statements about biosynthesis of Abscisic acid ;

a) ABA is synthesized in almost all cells that contain chloroplasts or amyloplasts

b) ABA is a 15-carbon terpenoid, or sesquiterpenoid, which is synthesized in plants by an indirect pathway via 40-carbon carotenoid intermediates

c) Cleavage of the carotenoid by the enzyme NCED (9-cis-epoxycarotenoid dioxygenase) is a rate-limiting

d) Oxidation by ABA-8′-hydroxylases lead to ABA inactivation, ABA can also be inactivated by conjugation, but this is irreversible. Both types of inactivation are also tightly regulated.

Which of the following  combination from the above statements  is correct?

#Question id: 10355

#Unit 6. System Physiology – Plant

The conversion of ammonium to amino acids requires two enzymes such as GS and GOGAT,

a) High levels of light and carbohydrate—conditions that stimulate plastid GS and Fd-GOGAT

b) Conditions of ample energy inhibit GS and GOGAT

c) The stimulation of GS and GOGAT, they favor nitrogen assimilation into glutamine and glutamate, compounds that are rich in carbon and participate in the synthesis of new plant materials

d) In energy-limited conditions inhibit GS and GOGAT

Which of the following statements about GS and GOGAT is correct?

#Question id: 10358

#Unit 6. System Physiology – Plant

Which of the following essential micronutrients is associated with nitrate reductase enzyme found in higher plants?

#Question id: 10359

#Unit 6. System Physiology – Plant

Nitrate reductases of higher plants are composed of two identical subunits, each containing three prosthetic groups. Which of the following is not the prosthetic group of nitrate reductase;

#Question id: 10362

#Unit 6. System Physiology – Plant

Bacteria can convert atmospheric nitrogen into ammonia, Several form symbiotic associations with higher plants is given below;

               HOST PLANT                                                                          N-FIXING SYMBIONTS

A) Gunnera                                                                            i) Frankia

      B) Azolla                                                                                ii) Acetobacter

C) Leguminous                                                                     iii) Azospirillum

             D) Actinorhizal                                                                      iv) Nostoc

             E) Sugarcane                                                                         v) Anabaena

             F) Miscanthus                                                                       vi) Sinorhizobium

Which of the following combination with the host plants and n-fixing symbionts is CORRECT?

#Question id: 10368

#Unit 6. System Physiology – Plant

Free-living bacteria that are capable of fixing nitrogen are aerobic, facultative, or anaerobic. Some of the Aerobic nitrogen-fixing bacteria such as

#Question id: 10369

#Unit 6. System Physiology – Plant

Which type of the nitrogen-fixing bacteria are thought to maintain a low oxygen concentration (microaerobic conditions) through their high levels of respiration