NADPH

Question 1

What pathway produces NADPH?

Answer 1

The pentose phosphate pathway (PPP), also called the hexose monophosphate shunt

Question 2

What is NADPH?

Answer 2

An important electron donor used in various biological processes

Question 3

What are the primary outputs of the PPP?

Answer 3

NADPH, ribose 5-phosphate, and erythrose 4-phosphate

Question 4

Where does the PPP occur?

Answer 4

In virtually all cells and tissues

Question 5

What phase of the PPP produces NADPH?

Answer 5

The oxidative (irreversible) phase

Question 6

What enzyme regulates NADPH production in the PPP?

Answer 6

Glucose-6-phosphate dehydrogenase (G6PD)

Question 7

What is the rate-limiting step of the PPP?

Answer 7

Oxidation of G-6-P to 6-phosphogluconate by G6PD

Question 8

What controls the reaction rate of the PPP?

Answer 8

The ratio of NADPH to NADP+

Question 9

What is the main use of NADPH in cells?

Answer 9

Reductive biosynthesis, especially fatty acid synthesis

Question 10

What percentage of NADPH is used for fatty acid synthesis?

Answer 10

Approximately 50%

Question 11

How does NADPH help the liver and red blood cells?

Answer 11

By reducing oxidative stress

Question 12

What role does NADPH play in CYP450 enzyme function?

Answer 12

It helps neutralize toxins and hormones

Question 13

What does NADPH do in white blood cells?

Answer 13

Produces superoxide radicals to destroy microbes

Question 14

What do glands use NADPH for?

Answer 14

Steroid hormone synthesis

Question 15

Where is PPP activity minimal?

Answer 15

In muscle and brain tissues

Question 16

What percentage of liver glucose is metabolized by the PPP?

Answer 16

Around 30%

Question 17

Where is PPP activity especially high due to oxidative stress?

Answer 17

In the cornea and red blood cells

Question 18

What are reactive oxygen species (ROS)?

Answer 18

Powerful oxidants that can damage biological molecules

Question 19

Examples of ROS?

Answer 19

Ozone (O₃), hydrogen peroxide (H₂O₂), and superoxide (O₂⁻)

Question 20

What diseases are associated with ROS?

Answer 20

Lung fibrosis, atherosclerosis, inflammation, and tissue damage

Question 21

What does GSH reductase do?

Answer 21

Uses NADPH to convert GSSG to GSH

Question 22

What does GSH peroxidase do?

Answer 22

Uses GSH to reduce peroxides to water or alcohol

Question 23

What does superoxide dismutase (SOD) do?

Answer 23

Converts superoxide to hydrogen peroxide

Question 24

What does catalase do?

Answer 24

Converts hydrogen peroxide into water

Question 25

What is G6PD deficiency?

Answer 25

A genetic disorder that reduces NADPH production

Question 26

How common is G6PD deficiency globally?

Answer 26

Present in 7.5% of the population

Question 27

Why is G6PD deficiency more common in males?

Answer 27

It is X-linked and recessive.

Question 28

What does G6PD deficiency lead to?

Answer 28

Reduced GSH regeneration and increased haem oxidation, causing haemolytic anaemia

Question 29

What can exacerbate G6PD deficiency?

Answer 29

Oxidative-inducing drugs (e.g., anti-malarials) and foods (e.g., fava beans)