Glycolysis

Question 1

What is glycolysis?

Answer 1

the metabolic pathway that converts glucose into pyruvate, generating ATP

Question 2

Where does glycolysis take place?

Answer 2

Cytosol

Question 3

What are the net products from glycolysis?

Answer 3

2 pyruvate + 2NADH + 2ATP + 2H⁺ + 2H₂O

Question 4

What are the net reactants of glycolysis?

Answer 4

• Glucose
• 2 P_i
• 2 ADP
• 2NAD+

Question 5

What is a signal for low energy levels?

Answer 5

AMP

Question 6

What enzmye catalyses transfer of phosphate from one ADP to another?

Answer 6

Adenylate kinase

Question 7

What reaction does adenylate kinase catalyse?

Answer 7

ADP + ADP ⇄ ATP + AMP

Question 8

Where does fructose in adipose tissue enter glycolysis?

Answer 8

Fructose-6-phosphate

Question 9

What enzyme changes fructose into fructose-1-phosphate?

Answer 9

Fructokinase

Question 10

Where does galactose enter the glycolytic pathway?

Answer 10

Glucose-6-phosphate

Question 11

What enzyme is involved in the reaction from glucose-1-phosphate to glucose-6-phosphate?

Answer 11

Phosphoglucomutase

Question 12

What enzyme converts galactose to galactose-1-phosphate?

Answer 12

Galactokinase

Question 13

Outline how galactose enters the glycolytic pathway

Answer 13

• Converted into galactose-1-phosphate
• Galactose-1P reacts with UDP-glucose to produce UDP-galactose and glucose-1-phosphate
• Phophate is transferred from C1 to C6 producing glucose-6-phosphate

Question 14

What enzyme catalyses the reaction between galactose-1-phosphate and UDP-glucose?

Answer 14

Galactose-1-phosphate uridyl transferase

Question 15

Give the reaction which allows lactose to enter glycolysis

Answer 15

Lactose + H₂O → glucose + galactose

Question 16

Which enzyme is responsible for the reaction of lactose into glucose and galactose?

Answer 16

Lactase

Question 17

What do high levels of ATP do to glycolysis?

Answer 17

Inhibit it

Question 18

Which is the main enzyme involved in glycolysis regulation?

Answer 18

Phosphofructokinase

Question 19

What 3 enzymes are involved in the control of glycolysis?

Answer 19

• Phosphofructokinase
• Hexokinase
• Pyruvate Kinase

Question 20

How does ATP inhibit PFK?

Answer 20

Allosterically

Question 21

How does AMP reverse the inhibition of PFK?

Answer 21

It binds to the same allosteric site as ATP but does not inhibit PFK

Question 22

What reverses inhibition of PFK?

Answer 22

AMP

Question 23

What inhibits hexokinase?

Answer 23

Glucose-6-phosphate

Question 24

What inhibits pyruvate kinase?

Answer 24

• ATP
• Alanine

Question 25

What inhibits phosphofructokinase?

Answer 25

• ATP
• Citrate
• H+

Question 26

How is the inhibition of hexokinase lifted during exercise in glycolysis?

Answer 26

• A greater proportion of AMP relative ATP stimulates PFK
• This uses up glucose-6-phosphate so hexokinase is no longer inhibited

Question 27

What stimulates PFK?

Answer 27

• AMP
• Fructose-2,6-bisphosphate

Question 28

What stimulates pyruvate kinase?

Answer 28

• Fructose-1,6-bisphosphate

Question 29

What enzyme is involved in the reaction of pyruvate to lactate?

Answer 29

Lactate dehydrogenase

Question 30

What happens to electrons in fermentation?

Answer 30

They are transferred from pyruvate to an organic molecule

Question 31

What is the reaction of lactate fermentation?

Answer 31

2 pyruvate → 2 lactate

Question 32

What is the reaction of alcoholic fermentation?

Answer 32

Pyruvate + NADH⁺ + H⁺ → Ethanol + CO₂ + NAD⁺