In dark-adapted rod cells, a high level of cGMP keeps cGMP-gated nonselective cation channels open, leading to hyperpolarization of the plasma membrane and neurotransmitter release. 

B - Light absorption generates activated rhodopsin, R*, which binds inactive, GDP-bound Gαt protein and mediates the exchange of GDP for GTP . 

C- The free Gαt∙GTP activates PDE by binding to its inhibitory γ subunits and dissociating them from the catalytic α and β subunits . Relieved of their inhibition, the α and β subunits of PDE hydrolyze GMP to cGMP . 

D- The resulting decrease in cytosolic cGMP leads to dissociation of cGMP from the cation channels in the plasma membrane and the closing of those channels . 

E- The membrane then becomes transiently hyperpolarized, and neurotransmitter release is reduced. 

#Question id: 27947

#Unit 1. Structure and Function of Biomolecules

For each molecule of glucose degraded to pyruvate, two molecules of ATP are generated from ADP and Pi, and two molecules of NADH are produced by the reduction of NAD+. The hydrogen acceptor in this reaction is NAD+  this NAD+ bound to a

#Question id: 27948

#Unit 1. Structure and Function of Biomolecules

#Question id: 27949

#Unit 1. Structure and Function of Biomolecules

Which of the following reaction is catalyzed by enzyme phosphohexose isomerase (phosphoglucose isomerase)

#Question id: 27950

#Unit 1. Structure and Function of Biomolecules

Some of the properties of Hexokinases I, II, III & IV is given

a. Hexokinases I, II, and III shows hyperbolic curve of glucose binding while Hexokinase IV shows sigmoidal curve 

b. Accumulation of glucose 6-phosphate inhibits hexokinases I–III by feedback mechanism 

c. Accumulation of glucose 6-phosphate allosterically inhibits hexokinases I–III.

d. The allosteric effector of Hexokinase IV is fructose 6-phosphate.

Which of the following is incorrect  

#Question id: 27951

#Unit 1. Structure and Function of Biomolecules

#Question id: 27952

#Unit 1. Structure and Function of Biomolecules