TLS Online TPP Program

#Question id: 10342


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?

#Unit 6. System Physiology – Plant
  1. A and D         
  2. B and C
  3. C and D             
  4. A and B
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TLS Online TPP Program

#Question id: 24211

#Unit 1. Molecules and their Interaction Relevant to Biology

Plot of hexokinase IV (Glucokinase) is different While Hexokinases I, II, and III have similar kinetic properties. So, in given graph which of the following represents hexokinase IV and Hexokinases I, II, and III
a. i is representing Hexokinases IV
b. ii is representing Hexokinases I, II, and III
c. i is representing Hexokinases I, II, and III
d. ii is representing Hexokinases IV
Choose the correct option

TLS Online TPP Program

#Question id: 24210

#Unit 1. Molecules and their Interaction Relevant to Biology

The human genome encodes four different hexokinases (I to IV), all of which catalyze the same reaction. If Two or more enzymes that catalyze the same reaction but are encoded by different genes are called to be

TLS Online TPP Program

#Question id: 24209

#Unit 1. Molecules and their Interaction Relevant to Biology

Two enzyme having same reaction mechanism using same cofactor such as PDC and KDC

TLS Online TPP Program

#Question id: 24208

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the true substrate for hexokinase

TLS Online TPP Program

#Question id: 14146

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following

Column A Column B 
A. Cyanide1. Inhibit cytochrome oxidase
B. Piericidin A2. Prevent electron transfer from Fe-S center to ubiquinone              
C. Antimycin A        3. Blocks electron transfer from cytochrome b to cytochrome c1
D. Valinomycin4. K+ ionophore

TLS Online TPP Program

#Question id: 543

#Unit 1. Molecules and their Interaction Relevant to Biology

If glucose labeled with 14C at C-1 (the aldehyde carbon) were metabolized in the liver, the first radioactive pyruvate formed would be labeled in: