Carbohydrate Metabolism

Question 1

What is glycolysis

Answer 1

The breakdown of a 6 carbon glucose molecule to produce a 3 carbon molecule of pyruvate

Question 2

Which cells in the body can generate energy from glycolysis

Answer 2

Every cell in the body

Question 3

How many steps are in glycolysis

Answer 3

10

Question 4

In what type of cells is glycolysis the only energy pathway

Answer 4

Cells without a mitochondria

Question 5

Which hormone activates glycolysis in resting conditions

Answer 5

Insulin

Question 6

Which hormone inhibits glycolysis in resting conditions

Answer 6

Glucagon

Question 7

In what conditions are we heavily reliant on anaerobic glycolysis

Answer 7

During severe intensity exercise (1-5 minutes) or when the PCR system has been depleted

Question 8

What is the maximal rate of ATP synthesis using glycolysis

Answer 8

4.5 mmol/Kg

Question 9

What is the time required to maximise ATP rates when exercise starts with glycolysis

Answer 9

5-10 seconds

Question 10

What is the investment phase of glycolysis

Answer 10

First 5 reactions, ATP is used

Question 11

What is the payoff phase of glycolysis

Answer 11

Reactions 6-10 where ATP is generated

Question 12

What is the first step of glycolysis

Answer 12

Glucose is converted to glucose-6-phosphate by hexokinase (addition of phosphate to carbon 6), ATP is used

Question 13

What is the function of the enzyme phsophofructokinase in step 3 of glycolysis

Answer 13

Converts fructose-6-phosphate to fructose 1,6-bisphosphate (addition of another phosphate to C1), ATP is used

Question 14

What is the function of pyruvate kinase in the final step of glycolysis

Answer 14

Convert PEP to pyruvate by removing phosphate, ATP generated

Question 15

How many total molecules of ATP and how many net molecules of ATP does glycolysis produce per molecule of glucose

Answer 15

4 total, 2 net

Question 16

Which type of glycolysis produces large amounts of lactic acid

Answer 16

Anaerobic

Question 17

What is glycogenesis

Answer 17

Formation of new glycogen

Question 18

What is glycogenolysis

Answer 18

Breakdown of glycogen

Question 19

What are the two main sites of glycogen storage in the body

Answer 19

Liver and muscle

Question 20

Which is the largest glycogen store in the body

Answer 20

Muscle

Question 21

How is glucose released from glycogen in muscle

Answer 21

Released as glucose-6-phosphate specifically for muscle tissue

Question 22

What is the difference between glucose released in liver and muscle cells

Answer 22

Glucose is released specifically for muscle from muscle stores, liver stores release glucose for other cells also

Question 23

What is the function of phosphoglucomutase in glycogenesis

Answer 23

Moves phosphate from C6 to C1 in glucose-6-P to produce glucose-1-P

Question 24

What does glucose-1-P bind to during glycogenesis to produce UDP glucose

Answer 24

UTP

Question 25

Which enzyme attaches UDP glucose to other glucose molecules via alpha1-4 glycosidic linkages to form glycogen in glycogenesis

Answer 25

Glycogen synthase

Question 26

When are glycogen molecules branched

Answer 26

After 11 or more chains have been formed

Question 27

Which enzyme is required to break the alpha1-4 linkage in glycogen produced by glycogen synthase and reattach via alpha 1-6 linkages to form branches

Answer 27

Branching enzyme

Question 28

How is glucose removed from the glycogen chain

Answer 28

Phosphorolysis

Question 29

How much if the glycogen chain is broken down into glucose

Answer 29

Around 10%

Question 30

How much of the glycogen chain is broken down into glucose-1-P

Answer 30

About 90%

Question 31

Which enzyme is the rate limiting step in glycogenolysis

Answer 31

Glycogen phosphorylase

Question 32

What is the role of glycogen phosphorylase in glycogenolysis

Answer 32

Breaks down the alpha 1-4 bonds until there is 4 glucose molecules remaining

Question 33

What happens to the glucose-1-P released from the chain

Answer 33

Converted to glucose-6-P which is then used in glycolysis for energy or converted to glucose in the liver

Question 34

Which enzymes break the 1-6 linkages

Answer 34

Debranching enzyme and glucan transferase

Question 35

When is glycogenolysis unregulated in skeletal muscle

Answer 35

During high intensity exercise