Nitrate reductase is an important enzyme for nitrate assimilation. Given below some regulation of nitrate reductase activity through phosphorylation and dephosphorylation.

a) Light, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby activates the enzyme

b) In Dark, and Mg2+ stimulate a protein kinase that phosphorylates the same serine residues, which then interact with a 14-3-3 inhibitor protein, and thereby inactivate nitrate reductase

c) In Light, and Mg2+ stimulate a protein kinase that phosphorylates the serine residues, and thereby activate nitrate reductase

d) In Dark, and other environmental factors stimulate a protein phosphatase that dephosphorylates a key serine residue in the hinge 1 region of nitrate reductase and thereby inactivates the enzyme

Which of the following statements about regulation of nitrate reductase is correct?

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#Question id: 11788

#Unit 7. System Physiology – Animal

During the first few years after menopause, follicle-stimulating hormone (FSH) levels are normally extremely high. A 56-year-old woman completed menopause 3 years ago. However, she is found to have low levels of FSH in her blood. Which of the following is the best explanation for this finding?

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#Question id: 11789

#Unit 1. Molecules and their Interaction Relevant to Biology

Starch is made up of amylose and amylopectin having (α1→4) and (α1→6) bonds, hence molecule have

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#Question id: 11790

#Unit 1. Molecules and their Interaction Relevant to Biology

Chitin is a polysaccharide

TLS Online TPP Program

#Question id: 11791

#Unit 1. Molecules and their Interaction Relevant to Biology

Cellulose act as hydrophobic molecule due to

TLS Online TPP Program

#Question id: 11792

#Unit 1. Molecules and their Interaction Relevant to Biology

Hyaluronic acid is an important glycosaminoglycan component of connective tissue. Hyaluronate molecules are composed of

A. D-glucuronic acid and N-acetyl-D-glucosamine

B. D-galactose and N-acetyl-D-glucosamine

C. β(1→4) and β(1→3) alternate linkages

D. β(1→4) and β(1→6) alternate linkages

Which of the above 2 combinations are correct

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#Question id: 11793

#Unit 1. Molecules and their Interaction Relevant to Biology

On the proteoglycan the glycosaminoglycan chain can bind to extracellular proteins through