#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___
#Question id: 11818
#Unit 6. System Physiology – Plant
Cytokinin
signals to nuclear-localized response regulators by transferring the phosphate group to an
aspartate on the receiver domain of the ARR. The ARR response regulators are
encoded by multigene families, They fall into two basic classes:
I) Type-A ARRs
II)Type-B ARRs
a) The products of which are made up solely of a receiver
domain
b) Receiver domain also include an output domain containing
DNA-binding transcription activation
sites
c)
Which negatively regulate cytokinin signaling by interacting with other
proteins in a manner dependent on the phosphorylation state
d) Which are activated by phosphorylation, which enables
them to regulate the transcription of a set of target genes
e) Which are targeted by F-box proteins called KISS ME
DEADLY (KMD) proteins negatively regulates the cytokinin response
Which of the following are the correct explanation of the given ARRs types classes of response regulator?