During an experiments mutating the conserved cysteine in the LOV1 domain of phot1 does not affect phototropic responsiveness (the seedlings bend toward blue light) whereas the equivalent mutation in LOV2 abolishes the response. What will be the conclusion has been drawn from this experiments?

a)  LOV1 domain is secondarily responsible (primarily responsible is LOV2 domain) for kinase activation and LOV1 is not is coupled with the protein region Jα-helix that’s why it does not affect phototropic responsiveness

b) These studies have demonstrated that LOV2 domain is primarily responsible for kinase activation in response to blue light

c) This is due in part to the position of LOV2 within the phototropin molecule, where it is coupled to a protein region known as the Jα-helix

d) The function of LOV2 domain is thought to play a role in receptor dimerization by accomplishing the kinase activation in response to blue light

Which of the correct conclusion drawn from the above experiment?

#Question id: 10368

#Unit 6. System Physiology – Plant

Free-living bacteria that are capable of fixing nitrogen are aerobic, facultative, or anaerobic. Some of the Aerobic nitrogen-fixing bacteria such as

#Question id: 10369

#Unit 6. System Physiology – Plant

Which type of the nitrogen-fixing bacteria are thought to maintain a low oxygen concentration (microaerobic conditions) through their high levels of respiration

#Question id: 10370

#Unit 6. System Physiology – Plant

Rhizobial genes that participate in nodule formation are called nodulation (nod) genes. Only one of the nod genes, the regulatory and constitutively expressed and regulates the transcription of the other nod genes;

#Question id: 10371

#Unit 6. System Physiology – Plant

There are three essential nod gene for every bacterial species that is−NodA, NodB and NodC, that are required for synthesizing this basic structure such as;

a) NodA is an N-acyltransferase that catalyzes the addition of a fatty acyl chain

b) NodB is a chitin-oligosaccharide synthase that links the acetyl group of the terminal nonreducing sugar

c) NodC is a chitin-oligosaccharide synthase that links N-acetyl-D-glucosamine monomers

d) NodB is a chitin-oligosaccharide deacetylase that removes the acetyl group from the terminal nonreducing sugar

e) NodC is a chitin-oligosaccharide deacetylase that removes links N-acetyl-D-glucosamine monomers

Which of the following statements about NOD Factor is incorrect?

#Question id: 10372

#Unit 6. System Physiology – Plant

Nod genes, which NodD activates, code for nodulation proteins, most of which are involved in the biosynthesis of Nod factors such as;

 a) Nod factors are lipochitin oligosaccharide signal molecules

 b) Nod factor shave a chitin β-1→ 4-linked N-acetyl-D-glucosamine backbone

 c) These N-acetyl-D-glucosamine backbone varying in length from three to six sugar units

 d) A fatty acid chain on the C-2 position of the nonreducing sugar determine the length and degree of saturation of the fatty acyl chain by NodL

 Which of the following is incorrect?

#Question id: 10373

#Unit 6. System Physiology – Plant

The nodulation (nod) genes are classified as common nod genes or host specific nod genes. Some statements related to such classification are given below;

a) nod A is a common nod gene and nod Q is a host specific gene

b) nod B is a common nod gene and nod C is a host specific gene

c) nod C is a common nod gene and nod H is a host specific gene

d) nod H is a common nod gene and nod P is a host specific gene

Choose the correct answer from the above statements: