Following statement regarding to acrosome reaction in sea urchin.

A. Activation of the acrosome reaction serves as a barrier to intraspecies fertilizations.

B. The acrosome reaction is initiated by sulfate-containing polysaccharides in the egg jelly that bind to specific receptors located directly above the acrosomal vesicle on the sperm cell membrane.

C. These polysaccharides are often highly species specific, but egg jelly factors from one species of sea urchin generally activate the acrosome reaction in closely related species.

D. The elevated Ca2+ level in a relatively basic cytoplasm triggers the fusion of the acrosomal membrane with the adjacent sperm cell membrane, releasing enzymes that can lyse a path through the egg jelly to the vitelline envelope.

Which of the following statements are correct?

#Question id: 10380

#Unit 6. System Physiology – Plant

Two separate processes, the first involves a signaling pathway that facilitates the infection process itself and  the second involves the activation of a set of genes that regulate the formation of root nodules. Which of the following receptor is thought to participate in both processes?

#Question id: 10381

#Unit 6. System Physiology – Plant

symbiosis receptor-like kinase (SYMRK) is another type of receptor involves several function. Which of the following is incorrect?

#Question id: 10382

#Unit 6. System Physiology – Plant

Ureides are

#Question id: 10383

#Unit 6. System Physiology – Plant

The nitrogenase enzyme complex fixes N2 produces ammonia, The nitrogenase enzyme complex catalyzes this reaction by following characteristics given below;

a) It can be separated into two components—the Fe protein and the MoFe protein— neither of which has catalytic activity by itself

b) Fe protein is the smaller of the two components and has two identical subunits, each contains an iron–sulfur cluster, which participates in the redox reactions

c) The Fe protein is irreversibly inactivated by O2 while MoFe protein is activated by O2

d) MoFe protein has four subunits, each subunit has two Mo–Fe–S clusters

e) Ferredoxin serves as an electron donor to the Fe protein, and Fe protein reduces the MoFe protein without any hydrolysing ATP

f) Only prokaryotes have nitrogenase enzyme

Which of the following characteristics of nitrogenase enzyme complex is incorrect?

#Question id: 10384

#Unit 6. System Physiology – Plant

Nitrogenase enzyme complex catalyzes the molecular nitrogen fixation, this enzyme not only fixes nitrogen but also perform other reactions given below. Which one is not performed by nitrogenase?

#Question id: 10385

#Unit 6. System Physiology – Plant

The leaves of many species are able to bend toward the sun during its progress across the sky, a phenomenon known as