L13: Glycolysis

Question 1

Key points of glycolysis

Glycolysis

1. Definition:
2. Location:
3. Tissues:
4. Functions:

Answer 1

1. Glucose C6 -> 2 pyruvate C3
2. Cytosol
3. All tissues
4. ‘Energy’ trapping

Question 2

3 functions of glycolysis

Answer 2

1. ‘Energy’ trapping (ATP synthesis)
2. Intermediates for fat synthesis
3. Intermediates for amino acid synthesis

Question 3

Sources of glucose for glycolysis

Answer 3

1. Sugars & starch from diet
2. Breakdown of stored glycogen from liver
3. Recycled glucose

Question 4

4 stages of glycolysis

Answer 4

1. Activation (using up ATP)
2. Splitting 6C sugar in half
3. Oxidation (removing 2H atoms)
4. Synthesis of ATP

Question 5

Glycolysis

Describe Reaction 1 in glycolysis

Answer 5

1. Glucose is trapped within cells by adding negatively charged phosphate
2. ATP is used to attach phosphate ‘ATP’ catalysed by hexokinase

Question 6

What happens in Reaction 1 of glycolysis?

Answer 6

D-glucose uses ATP to attach a phosphate catalysed by hexokinase to produce **glucose 6-phosphate **

Question 7

What happens in reaction 2 of glycolysis?

Answer 7

Glucose 6-phosphate is catalysed by **phosphohexose isomerase **to produce **fructose 6-phosphate **

Question 8

DESCRIBE reaction 2 in glycolysis

Answer 8

Switch from aldose to ketose sugar

Question 9

What happens in Reaction 3 of glycolysis?

Answer 9

Fructose 6-phosphate is catalysed by PFK using ATP to produce fructose 1,6-biphosphate

Question 10

Reaction 4

What happens during the splitting of 6C to 3C?

Answer 10

Fructose 1,6-biphosphate is split in half using Aldose to produce GaP & DhaP

Question 11

Reaction 5: Splitting 6C to 3C

Function of triose phosphate isomerase

Answer 11

Catalyse the reaction to convert DhaP to GaP

Question 12

Reaction 6: Oxidation

What happens during oxidation stage?

Answer 12

GaP uses NAD+ which is catalysed by GaPah to produce 1,3-biphosphoglycerate

Question 13

Reaction 6

Describe oxidation stage

Answer 13

NaDH produced in this stage will be used in oxidative phosphorylation to generate ATP

Question 14

What happens in Reaction 7 of glycolysis?

Answer 14

1,3-biphosphoglycerate catalysed by phosphoglycerate kinase & uses 2x ATP to produce 3-phosphoglycerate

Question 15

How does ATP form from ADP by substrate level phosphorylation?

Answer 15

Substrate-level phosphorylation is the direct formation of ATP or GTP by transferring a phosphate group from a high energy compound to an ADP or GDP molecule.

Question 16

What happens in Reaction 8- isomerisation in glycolysis?

Answer 16

3-phosphoglycerate catalysed by phosphoglycerate mutase to produce 2-phosphoglycerate

Phosphate moved around

Question 17

What happens during Reaction 9 of glycolysis?

Answer 17

2-Phophoglycerate releases H2O and catalysed by enolase to produce PEP (phosphoenol pyruvate)

Question 18

What happens during Reaction 10 (Substrate level phosphorylation)?

Answer 18

PEP produces ATP and catalysed by pyruvate kinase (irreversible enzyme) to produce pyruvate

Question 19

Define substrate level phosphorylation

Answer 19

Substrate-level phosphorylation is the direct formation of ATP or GTP by transferring a phosphate group from a high energy compound to an ADP or GDP molecule

Question 20

Define anaerobic glycolysis

Answer 20

Transformation of glucose to lactate when limited amounts of oxygen (O2) are available.

Question 21

Equation for anaerobic glycolysis

Answer 21

Pyruvate + NADH + H+ -> NAD+ + lactate

Question 22

Role of lactate dehydrogenase in muscle

Answer 22

Catalyse the interconvention of pyruvate to lactate

Question 23

What happens in lactate dehydrogenase?

Answer 23

Reversible reaction that uses NADH to convert pyruvate to lactate

Question 24

Specialised functions in skeletal muscle

Answer 24

ATP production during intense exercise

Question 25

Specialised functions in red blood cells

Answer 25

Only pathway for ATP production

Question 26

Specialised functions in brain

Answer 26

Major source of ATP