Lecture 30: Pentose Phosphate Pathway

Question 1

What is the purpose of the Pentose Phosphate pathway?

Answer 1

Alternate pathway for oxidation of glucose, synthesizes pentoses, produces NADPH

Question 2

What is the rate limiting step of the Pentose Phosphate pathway?

Answer 2

The initial Glucose-6-phosphate dehydrogenase step

Question 3

What condition is marked by low levels of NADPH, which inhibits altered G6PD and leads to low levels of reduced glutathione in red blood cells?

Answer 3

Hemolytic anemia

Question 4

What is needed to maintain healthy red blood cell membranes?

Answer 4

Reduced glutathione

Question 5

What is significant about the oxidative phase of the pentose phosphate pathway?

Answer 5

NADPH is formed which can be fed into glutathione reduction or fatty acid synthesis

Question 6

What is significant about the non-oxidative phase of the pentose phosphate pathway?

Answer 6

Depending on the cell’s energy needs, intermediates can be fed back into other pathways such as glycolysis, gluconeogenesis, TCA, etc.

Question 7

Mode 1 of PPP

Answer 7

Much more ribose-5-phosphate than NADPH required; doesn’t commit to glycolysis or NADPH (ribose focused)

Question 8

Mode 2 of PPP

Answer 8

The needs for NADPH and ribose-5-phosphate are balanced; both are generated

Question 9

Mode 3 of PPP

Answer 9

Much more NADPH than ribose-5-phosphate required; all geared toward NADPH production

Question 10

Mode 4 of PPP

Answer 10

Both NADPH and ATP are required; NADPH generated, glycolysis also occurs to make ATP