Pentose Phosphate Pathway

Question 1

the pentose phosphate pathway is the alternate pathway for the oxidation of

Answer 1

glucose

Question 2

The pentose phosphate pathway synthesizes ______, _______, and _____

Answer 2

pentoses, ribose, and doexyribose

Question 3

The pentose phosphate pathway produces ______ needed for reductive biosynthesis, ex. cholesterol synthesis

Answer 3

NADPH

Question 4

what is the initial rate limiting step

Answer 4

-Glucose 6-Phosphate dehydrogenase

Question 5

• Glucose-6-phosphate dehydrogenase is deficient in what disease

Answer 5

hemolytic anemia

Question 6

G6PD catalyzes

Answer 6

glucose-6-phosphate + (NADP+) —–> NADPH + (H+) + 6-Phosphoglucono-delta-lactone)

Question 7

What reaction does Glutathione reductase catalyze

Answer 7

Oxidized glutathione (GSSG) + NADPH + H+ ——–> Reduced glutathione

Question 8

Glutathione reductase is inhibited by low levels of ______, leading to low levels of reduced glutathione in red blood cells

Answer 8

NADPH

Question 9

What causes hemolytic anemia

Answer 9

altered PPP leads to low NADPH which is required by Glutathione reductase to reduce glutathione

Question 10

What are the two phases of the PPP

Answer 10

phase one is oxidative

phase two is nonoxidative

Question 11

The complete oxidation of G-6-P to ribulose 5-P in phase 1 of the PPP requires how many NADP+

Answer 11

2

Question 12

Lactonase catalyzes

Answer 12

6-Phosphoglucono-gamma-lactone + H2O ——–> 6-phosphogluconate + (H+)

Question 13

6-Phosphogluconate dehydrogenase catalyzes

Answer 13

6-Phospho-gluconate + (NADP+) ——–> Ribulose 5-Phosphate + CO2

Question 14

What mode of the PPP meets the needs of much more ribose-5-phosphate than NADPH

Answer 14

Mode 1

Question 15

Mode 1 of the PPP

Answer 15

• is non-oxidative
• much more ribose-5-phosphate than NADPH
• Makes ribose 5-P from Fructose-6-P and Glyceraldehyde 3-P

Question 16

Mode 2 of the PPP

Answer 16

• meets the needs for equal NADPH and ribose 5-P

- oxidative- G-6-P with 2 NADP+ ——> 2NADPH + CO2+ Ribose-5-Phosphate (note it initially makes Ribulose-5-Phosphate)

Question 17

What mode of PPP is used when needs for NADPH and ribose-5-P are balanced

Answer 17

Mode 2

Question 18

What mode of the PPP is used when the needs for NADPH are much more than the needs for ribose-5-P

Answer 18

Mode 3

Question 19

Mode 3 of PPP

Answer 19

• both oxidative and non-oxidative
• formation of ribose-5-P and 2NADPH from Glucose-6-P but then Ribose-5-P is used to make Fructose-6-P and glyceraldehyde-3-P

Question 20

what mode of the PP is used when both NADPH and ATP are needed

Answer 20

Mode 4

Question 21

Mode 4 of PPP

Answer 21

• both oxidative and non-oxidative
• • formation of ribose-5-P and 2NADPH from Glucose-6-P but then Ribose-5-P is used to make Fructose-6-P and glyceraldehyde-3-P, which is then used in glycolysis to make Pyruvate and ATP

Question 22

What negatively inhibits G6PD

Answer 22

NADPH