Pentose Phosphate Pathway

Question 1

What facilitates the conversion of Glucose-6-P to 6-Phosphogluconolactone?

Answer 1

Glucose-6phosphate dehydrogenase
[NADP+ -> NADPH]

Question 2

What was released during the conversion of 6-Phosphogluconolactone to 6-phosphogluconate?

Answer 2

H2O was used, releasing H+

Question 3

What facilitates the conversion of 6-Phosphogluconolactone to 6-phosphogluconate?

Answer 3

Lactonase

Question 4

What were released during the conversion of 6-Phosphogluconate to ribulose-5-Phosphate?

Answer 4

CO2 (Decarboxylation)
NADP+ –> NADPH

Question 5

What facilitates the conversion of 6-Phosphogluconate to ribulose-5-Phosphate?

Answer 5

6-phosphogluconate Dehydrogenase

Question 6

What are the fates of Ribulose-5-Phosphate?

Answer 6

Ribose-5-phosphate via isomerization

Xylulose-5-phosphate via epimerase

Question 7

What will the fate be when ribulose-5-phosphate is isomerized?

Answer 7

Ribose-5-phosphate

Question 8

What will the fate be when ribulose-5-phosphate is epimerized?

Answer 8

Xylulose-5-phosphate

Question 9

Describe what happens in the isomerization of ribulose-5-phosphate to ribose-5-phosphate

Answer 9

Ketone was converted to aldehyde

Question 10

Differentiate ribulose-5-phosphate and xylulose-5-phosphate

Answer 10

Differ in Chirality

Just Note: xylulose-5-phosphate is a diastereomer

Question 11

What is an essential component of transketolase?

Answer 11

Thianine pyrophosphate

Question 12

What does transketolase do?

Answer 12

This transfers 2 carbons from ribose-5-phosphate, leaving Glyceraldehyde 3-phosphate as a product

The 2C will be transferred to xylulose-5-phosphate converting into seduloheptose-7-phosphate

Question 13

What will be the fate of GA3P of PPP?

Answer 13

1. The GA3P can get fed into glycolysis when needed
2. Can be involved in Gluconeogenesis when needed
3. React with Seduloheptose-7-phosphate

Question 14

What happens with the reaction of GA3P and Seduloheptose-7-phosphate?

Answer 14

3C of seduloheptose-7-phosphate will be transferred to GA3P resulting to Fructose-6-Phosphate (6C).

While Seduloheptose-7-phosphatase becomes erythrose-4-phosphate (4C).

Question 15

What facilitates the reaction and conversion of GA3P and seduloheptose-7-phosphate into their products?

Answer 15

Transaldolase

Question 16

What is the fate of Fructose-6-Phosphate of PPP?

Answer 16

CAN be fed into glycolysis [depending on the body’s need]

Question 17

What will happen to erythrose-4-phosphate of PPP?

Answer 17

React with xylulose-5-phosphate from epimerization of ribulose-5-phosphate that’s just hanging around.

This will be facilitated by transketolase (TPP).

2C is taken from Xylu-5-P transferred to eryth.
Product: GA3P & Fructose-6-phosphate

Question 18

Phases of PPP?

Answer 18

Oxidative phase
Non-oxidative phase

Question 19

What are the oxidative phase of PPP?

Answer 19

Glucose—-> ribose-5-phophate & xylulose-5-phosphate

[step 1-4]

Question 20

Function of oxidative phase

Answer 20

Make NADPH & Ribose-5-phosphate

Question 21

Function of non-oxidative phase?

Answer 21

Make ribose-5-phosphate without making NADPH

Question 22

What is non-oxidative reaction also known as?

Answer 22

Carbon shuffling reactions