#Question id: 11588
#Unit 7. System Physiology – Animal
Correct and appropriate signal transduction processes are generally under strong selective pressure and are determined by the properties of the molecules involved, the concentrations of signal and receptor molecules, and the binding affinities between signal and receptor. Therefore, a hormone action is very specific in a species at any one point in time. However, there are examples of very diverse functions of a specific hormone between groups of organisms. For example, thyroxin, which is produced in all vertebrates and many invertebrates, can trigger growth, differentiation, metamorphosis, maturation, reproduction, behavior, temperature tolerance, osmoregulation, or seasonal adaptation depending on the organism in which it is produced. What is the most logical explanation for such different responses triggered by thyroxin in organisms?
#Question id: 11589
#Unit 7. System Physiology – Animal
The body's reaction to parathyroid hormone (PTH), raising plasma levels of calcium, can be opposed by:
#Question id: 11590
#Unit 6. System Physiology – Plant
Seed germination may require gibberellins for one of several possible steps:
#Question id: 11591
#Unit 6. System Physiology – Plant
Gibberellins biosynthesis completes in almost three organelles
#Question id: 11592
#Unit 6. System Physiology – Plant
Gibberellin biosynthesis precursor is____
#Question id: 11593
#Unit 6. System Physiology – Plant
Following are given stages of gibberellin biosynthetic
pathway;
a) Geranylgeranyl diphosphate (GGPP) is converted to
ent-kaurene via copalyl diphosphate
(CPP) in endoplasmic reticulum
b) In the endoplasmic reticulum, conversion of ent-kaurene
into GA12 or GA53 depending on whether the GA is hydroxylated at carbon 13
c) the conversion of GA12 or GA53 into other GAs in cytosol
proceeds with a series of oxidations at carbon 20
d) GA20 is then oxidized to the active gibberellin, GA1, by
a 3β-hydroxylation reaction
Which of the following is the correct statements of GA biosynthesis?