Metabolism 1- glycolysis

Question 1

What is metabolism?

Answer 1

All the chemical reactions that maintain the living state of an organism

Question 2

What does anabolism mean?

Answer 2

The build up of molecules which requires energy.

Question 3

What does catabolism mean?

Answer 3

The breakdown of molecules which generates energy.

Question 4

What transfers glucose into the cell?

Answer 4

Na+ glucose symporters

Question 5

What are the different types of glucose transporters?

Answer 5

• GLUT 1, in brain , low Km
• GLUT 2, in liver, high Km, is insulin independent
• GLUT 3, brain, low Km
• GLUT 4, muscle + adipose tissue, insulin dependent
• GLUT 5, gut, fructose transport

Question 6

How does GLUT 1 transport glucose into the cell?

Answer 6

• Glucose binds which triggers an outer conformational change so that the binding site then faces inwards
• The glucose can be released in the inside
• Conformational changes regenerates the binding site outside

Question 7

What is the ATP net gain from glycolysis?

Answer 7

2 ATP molecules.

Question 8

How does pyruvate get into the matrix of the mitochondria?

Answer 8

First step through the outer membrane: Pyruvate moves across it through the pH gradient (dependent on the charges within the membrane)
Second step through the inner membrane: Pyruvate moves through with the H+ symport (facilitated diffusion)

Question 9

What does pyruvate dehydrogenase complex (PDC) do?

Answer 9

Catalyses the oxidative decarbonoxylation of pyruvate to acetyl co-A.

Question 10

What does pyruvate dehydrogenase complex (PDC) do?

Answer 10

Catalyses the irreversible oxidative decarbonoxylation of pyruvate to acetyl co-A.

Question 11

What happens when pyruvate is converted to acetyl co-A?

Answer 11

• redox reactions occur
• CO2 is produced
• NADH + H+ is produced
• 3 enzymes are involved

Question 12

What becomes the terminal electron acceptors in anaerobic conditions?

Answer 12

Lactate