Pentose Phosphate Pathway (complete)

Question 1

In what cells does the pentose phosphate pathway occur

Answer 1

all cells

Question 2

where in all cells does the pentose phosphate pathway occur

Answer 2

the cytoplasm

Question 3

What are the two branches of the pentose phosphate pathway

Answer 3

1. Oxidative Branch

2. Non Oxidative Branch

Question 4

What is the purpose of the pentose phosphate pathway

Answer 4

1. Production of NADPH

2. Production of Ribose-5-phosphate

Question 5

What does NADPH do

Answer 5

1. used in fatty acid synthesis
2. used in steroid synthesis
3. transformation of xenobiotics
4. reduction of oxidized glutathione

Question 6

What does Ribose-5-Phosphate do

Answer 6

Nucleotide synthesis (provides the sugar and phosphate portions of a nucleotide)

Question 7

From which intermediate in glycolysis does the oxidative branch of the pentose phosphate pathway branch off

Answer 7

Glucose-6-phosphate

Question 8

What is the initial enzyme used in the oxidative branch of the pentose phosphate pathway

Answer 8

Glucose-6-P dehydrogenase

Question 9

How Many NADPH are formed in the oxidative branch of the pentose phosphate pathway

Answer 9

2

Question 10

How many Ribose 5 phosphate are formed from the oxidative branch of the pentose phosphate pathway

Answer 10

1

Question 11

What regulates the activity of Glucose-6-Phosphate dehydrogenase (G6PDH)

Answer 11

NADPH

High levels of NADPH inactivate G6PDH

Question 12

Of the four reactions in the oxidative branch of the pentose phosphate pathway how many are irreversable

Answer 12

3 of the 4 are irreversable (first 3)

Question 13

Does NADPH mostly exist as NADPH or NADP+

Answer 13

NADPH

NADPH:NADP+ (100:1)

Question 14

Does NADH mostly exist as NADH or NAD+

Answer 14

NAD+

NADH:NAD+ (1;100)

Question 15

What vitamins are necessary for the synthesis of NADPH

Answer 15

Niacin and Vitamin B3

Question 16

In our lecture what was the most emphasized role of NADPH

Answer 16

the reduction of oxidized glutathione

Question 17

What does the reduction of oxidized glutathione allow glutathione to do

Answer 17

reduced glutathione can turn reactive oxygen species into water.

Question 18

What is the problem with having reactive oxygen species in our cells

Answer 18

they can damage membranes, proteins, and DNA

Question 19

What is the enzyme with the glutathione that NADPH will reduce

Answer 19

Glutathione peroxidase

Question 20

how does the reduction of oxidized glutathione work

Answer 20

1. Oxidized glutathione is reduced by NADPH
2. Reduced glutathione turns the reactive oxygen species into water. (glutathione becomes oxidized)
3. Another NADPH comes and reduces the oxidized glutathione again so it can turn another reactive oxygen species into water

Question 21

The deficiency of what enzyme in the body is the most common in humans

Answer 21

G6PDH deficiency

Question 22

What does G6PDH deficiency lead to in terms of

NADPH and GSH

Answer 22

low levels of NADPH

Low levels of GSH (reduced glutathione)

Question 23

What is GSH

Answer 23

reduced glutathione

Question 24

What is G-S-S-G

Answer 24

oxidized glutathione

Question 25

What are two effects of G6DPH deficiency

Answer 25

1. Malaria resistance

2. Hemolytic Anemia

Question 26

What cells are most affected by G6PDH deficiency

Answer 26

erythrocytes

Question 27

What is hemolytic anemia

Answer 27

Too many red blood cells dying, so the person becomes anemic

Question 28

What causes someone with G6PDH deficiency to get hemolytic anemia

Answer 28

Low NADPH = Low GSH = high amounts of reactive oxygen species

Question 29

From what sources can a person get the peroxide forming substances that can lead to anemia

Answer 29

Primaquine
Sulfonamide
Fava beans

Question 30

Which of the two effects of G6PDH deficiency can be a good side effect

Answer 30

Malaria resistance

Question 31

how does G6PDH deficiency lead to Malaria resistance

Answer 31

the erthyrocytes become altered, which makes them resistant to malaria

Question 32

From where in glycolysis does the non-oxidative branch of the pentose phosphate pathway break off

Answer 32

1. from fructose-6-phosphate

2. from one of the splitting intermediates after the splitting phase

Question 33

Is the non-oxidative branch of the pentose phosphate pathway reversable

Answer 33

yes. to both the frucotse 6 phosphate and the splitting intermediate

Question 34

what is the product of the non-oxidative branch of the pentose phosphate pathwya

Answer 34

ribose-5-phosphate

Question 35

Why is it significant that the non-oxidative branch of the pentose phosphate pathway is reversable

Answer 35

because the excess ribose-5-phosphate produced by both the non-oxidative and oxidative branches can be returned to the glycolysis/gluconeogenesis pathway.

Question 36

How many Ribose-5-Phosphates do you need to reverse the non-oxidative branch of the pentose phosphate pathway, and how many of each of the products do you get from those ribose-5-phosphates

Answer 36

3 ribose-5-phosphates are needed to reverse the non-oxidative branch. 2 fructose-6-phosphates and 1 splitting intermediate is formed.

Question 37

What are the main differences between the oxidative and non oxidative branches

Answer 37

the oxidative branch produces NADPH and ISN’T reversable

The non-oxidative branch DOESN’T produce NADPH and IS reversable

Question 38

What is the main similarity between the oxidative and non-oxidative branches

Answer 38

they both produce Ribose-5-Phosphate

Question 39

Which branch produces CO2

Answer 39

the oxidative branch

Question 40

What is the enzyme that reduces Oxidized glutathione back to reduced glutathione, and uses NADPH as a cofactor

Answer 40

Glutathione reductase