Energy production : carbohydrate 1

Question 1

What are the functions of glycolysis?

Answer 1

• oxidation of glucose
• 2 NADH per glucose molecule produced
• net of 2 ATP synthesised
• Produces C6 and C3 intermediates

Question 2

What are the features of Glycolysis?

Answer 2

• Central pathway of CHO catabolism
• Occurs in all tissues
• Exergonic and oxidative
• C6 –> 2C3
• Irreversible pathway
• only pathway that can operate anaerobically with LDH

Question 3

What are the major enzymes involved in glycolysis?

Answer 3

• Hexokinase
• Phosphofructokinase-1
• Pyruvate kinase

Question 4

Why so many steps involved in glycolysis?

Answer 4

• Efficient energy conservation
• allows interconnections with other pathways
• allows fine control

Question 5

Describe phase 1 of glycolysis

Answer 5

• Glucose phosphorylated to glucose-6-phosphate
  
  • make glucose (-) charged - prevents passage back across plasma membrane
• Increases reactivity of glucose to permit subsequent steps
• Uses 2 ATP per glucose
• Reaction 1&3 are irreversible

Question 6

Which step is the committing step and what is it?

Answer 6

• Step 3
• commits glucose to metabolism via glycolysis

Question 7

Describe Phase 2 of glycolysis

Answer 7

Reaction 4

• cleavage of C6 into 2C3
• C3 - interconvertible

Reaction 6

• small amount of reducing power captured (NADH)

Reaction 7 and 10 - ATP synthesis

• substrate level phosphorylation

Reaction 10

• large exothermic reaction - irreversible

Question 8

What is an example of clinical application of glycolysis?

Answer 8

• detect cancer
• rate of glycolysis is 200x greater in cancer
• measure uptake of FDG
• Imaging with positron emission tomography