Question

Pyruvate conversion to ethanol by yeast occurs

a) by a 10-step pathway

b) by a reaction that consumes ATP

c) to regenerate NAD+

d) under aerobic conditions (ample oxygen)

Gluconeogenesis

a) generates energy

b) is regulated

c) produces pyruvate at the expense of glucose

d) generates ATP and NADH

A type of reaction unique to gluconeogenesis compared to glycolysis is

a) isomerization between DHAP and GAP (dihydroxyacetone phosphate and glyceraldehyde-3-phosphate)

b) hydrolysis of phosphosugars

c) phosphorolysis to generate G-1-P (glucose-1-phosphate)

d) synthesis of pyruvate from PEP (phosphoenolpyruvate) in two steps

During arduous exercise

a) liver expends energy to synthesize glucose

b) lactate travels from the liver to the muscle where it is converted to pyruvate

c) cardiac muscle synthesizes glucose from pyruvate

d) energy production in cardiac muscle occurs solely by glycolysis

Answer 1

Ans-1- Pyruvate is converted into ethanol to regenerate NAD+ from NADH. Regenrated NAD+ is used in glycolysis to accept electrons. option C is correct.

Ans-2- gluconeogensis is the synthesis of glucose from a non-carbohydrate precursor like pyruvate. The process is under tight regulation and consumes 4 ATP, 2 GTP, and 2 NADH.

option C is correct.

Ans-3- in gluconeogenesis the first step is unique in which pyruvate is converted into PEP in two steps by two different enzymes. option D is correct.

Ans-4- under extreniuos excersize there is not enough oxygen available to muscle cells to produce ATP by aerobic respiration. So they produces ATP by substrate level phosphorylation only by using glycolysis.

option D is correct.