The diagram below represents a hypothetical operon in the bacterium E. coli.  The operon consists of two structural genes (A and B) that code for the enzymes A-ase and B-ase, respectively, and also includes P (promoter) and O (operator) regions as shown.

 When a certain compound (X) is added to the growth medium of E. coli, the separate enzymes A-ase and B-ase are both synthesized at a 50-fold higher rate than in the absence of X (which has a molecular weight of about 200).  Which one of the following statements is true of such an operon?

#Question id: 10378

#Unit 6. System Physiology – Plant

Nod factor as signaling agents binds with the nod factor receptor NFR on the basis for host–symbiont specificity, which of the following is incorrect?

#Question id: 10379

#Unit 6. System Physiology – Plant

Upon binding to Nod factors, activates the kinase activity of NFR1, this kianse activity of NFR1 activates which type of set of receptors?

#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?