Carbs 3

Question 1

What is the structure of glycogen?

Answer 1

• Polymer of glucose (a1-4) subunits

- a1-6 branches occur every 8-12 residues

Question 2

What does glycogenin do?

Answer 2

Covalently binds glucose from UDP-glucose to form chains of 8 subunits

Question 3

What enzyme takes over glycogenin after the primer has been made?

Answer 3

Glycogen synthase

Question 4

What enzyme breaks glycogen to form the 1-6 branching points?

Answer 4

Glycogen-branching enzyme

Question 5

How is glucose removed from glycogen?

Answer 5

As G-1-P

Question 6

What is the aim of glycolysis?

Answer 6

To save some of the potential energy from glucose as ATP through substrate level phosphorylation

Question 7

What stages are irreversible in glycolysis?

Answer 7

• Glucose to G-6-P
• F-6-P to F-1,6-Bisphosphate
• PEP to pyruvate

Question 8

What enzyme is used to convert glucose to G-6-P in glycolysis?

Answer 8

Hexokinase

Question 9

What enzyme is used to convert F-6-P to F-1,6-BP

Answer 9

Phosphofructokinase

Question 10

What enzyme is used to convert PEP to pyruvate?

Answer 10

Pyruvate Kinase

Question 11

What can pyruvate be used for in the human body?

Answer 11

• Converted to lactate in vigorously exercising muscle

- Converted to acetyl coA in aerobic conditions

Question 12

What is lactate dehydrogenase used for?

Answer 12

Converting lactate into pyruvate

Question 13

What is used by lactate dehydrogenase to make this conversion?

Answer 13

NAD+

Question 14

What does pyruvate dehydrogenase do?

Answer 14

Converts pyruvate into Acetyl CoA

Question 15

How is lactate made back into glucose?

Answer 15

Through gluconeogenesis in the liver.

Question 16

How does the cell bypass the unfavourable reactions in gluconeogenesis?

Answer 16

By using different enzymes that catalyse a different set of reactions

Question 17

How much glucose in grams is used by the brain as energy per day?

Answer 17

120g

Question 18

On average how much glucose can be produced from glycogen stores?

Answer 18

190g

Question 19

What is pyruvate first converted into to be reverted to PEP in gluconeogenesis

Answer 19

Oxaloacetate

Question 20

When does gluconeogenesis usually end?

Answer 20

F-6-P to G-6-P

Question 21

What is fructose converted into to be able to be used in glycolysis?

Answer 21

F-1-P

Question 22

How is F-1-P converted to F-6-P

Answer 22

Through internal rearrangement of the structure

Question 23

How can galactose be used in glycolysis?

Answer 23

It can be converted to glucose through UDP-glucose:galactose 1-phosphate uridylyltransferase

Question 24

What does the pentose phosphate pathway produce?

Answer 24

• NADPH

- Pentose sugars

Question 25

What are the two parts of the pentose phosphate pathway?

Answer 25

- Oxidative irreversible part | - Non-oxidative reversible part

Question 26

What does the oxidative part produce?

Answer 26

- NADPH | - Converts G-6-P into a pentose phosphate

Question 27

What does the non oxidative part produce?

Answer 27

Interconverts G-6-P and a pentose phosphate to form lots of 3, 4, 5, 6, 7 carbon sugars.

Question 28

What are some real life examples of enzyme and electron carrier deficiencies?

Answer 28

- Black water fever | - Inability to convert hydrogen peroxide as it requires NADPH

Question 29

What does glutamate combine with in the glucose alanine cycle in the tissues?

Answer 29

Pyruvate

Question 30

What does the combination of glutamate and pyruvate produce?

Answer 30

- Alpha ketoglutarate | - Alanine