Thyroid hormones are thermogenic, their actions on target tissues result in heat production by following mechanisms:

i. stimulation of Na+-K+ ATPase

ii. increased O2 consumption

iii. increased metabolic rate

iv. increase in the number and activity of mitochondria

which of the following combinations are correct regarding heat production?

#Question id: 11812

#Unit 6. System Physiology – Plant

The  nitrogens  at the 3, 7, and 9 positions of the adenine ring of cytokinins can be conjugated to glucose residues, Alanine can also be conjugated to the nitrogen at the 9 positon, forming

#Question id: 11813

#Unit 6. System Physiology – Plant

Cytokinin-overproducing plants exhibit several characteristics that point to roles played by cytokinin in plant physiology and development:

a) shoot apical meristems of cytokinin-overproducing plants produce more leaves.

b) Adventitious shoots may form from unwounded leaf veins and petioles.

c) Leaf senescence is retarded.

d) more extreme cytokinin-overproducing plants are stunted, with greatly shortened internodes.

e) Apical dominance is greatly increased

Which of the following statements of above given overproducing cytokinin plants is correct?

#Question id: 11814

#Unit 6. System Physiology – Plant

Simplified biosynthetic pathway for cytokinin biosynthesis followed given such steps;

a) isopentenyl transferase (IPT), is the addition of the isopentenyl side chain from DMAPP (dimethylallyl diphosphate) to an adenosine moiety (AMP)

b) iPRTP or iPRDP is converted to ZTP or ZDP respectively by cytochrome P450 monooxygenase  and eventually is converted to zeatin

c) The ribotide and riboside forms of trans-zeatin can be interconverted, and free transzeatin can be formed from the ribotide by the LONELY GUY (LOG) family of cytokinin

Which of the following steps is true of the cytokinin biosynthesis?

#Question id: 11815

#Unit 6. System Physiology – Plant

Some given statements about  the cytokinin signalling pathway;

a)  Cytokinin receptor CRE1 probably functions as a monomer

b) Two other hybrid sensor kinases (AHK2 and AHK3) may also act as cytokinin receptors in Arabidopsis

c) Activated receptor activates their histidine kinase activity, The phosphate is transferred to an aspartate residue (D) on the fused receiver domains

d) The phosphate is then transferred to a conserved histidine present in an AHP protein that transfer the phosphate to an aspartate residue  located within the receiver domain of type-B ARRs only

e) The phosphorylation of the type-B ARR activates the output domain to induce transcription of genes encoding type-A ARRs.

f) The phosphorylated type-A ARRs feed back to negatively regulate cytokinin signaling, thus dampening cytokinin responses

Which of the following are the correct prediction about cytokinin signalling?

#Question id: 11816

#Unit 6. System Physiology – Plant

Which of the following given statements are correct predict about negatively regulate signalling pathway?

#Question id: 11817

#Unit 6. System Physiology – Plant

In the cytokinin pathway a phosphotransfer AHP1 protein is also known as___