TCA cycle

Question 1

What is the net yield per cycle?

Answer 1

2CO2, 3NADH, FADH2, 3H+

*no ATP*

Question 2

Where in the cell does the TCA cycle take place?

Answer 2

mitochondrial matrix

Question 3

What are the substrates of the TCA cycle

Answer 3

• acetyl CoA
• other C sources
• oxidised cofactors (NAD+, FAD+)
• GDP + Pi

Question 4

What are the levels of control of the TCA cycle?

Answer 4

• whole body - endocrine and CNS control
• cellular - E levels, ATP:AMP/ADP, NADH:NAD+, regulatory enzymes

Question 5

What are the 3 main enzymes involved in the TCA cycle?

Answer 5

1. Citrate synthetase - converts acetyl CoA to isocitrate
2. isocitrate dehydrogenase - converts isocitrate to a-ketoglutarate
3. a-ketoglutarate dehydrogenase - converts a-ketoglutarate to succinyl CoA