TCA Cycle

Question 1

What is the krebb cycle

Answer 1

/process by which acetyl-CoA is oxidized to form ATP and NADH

Question 2

Mnemonic for TCA cycle mnemonic

Answer 2

Citrate 
Is 
Krebs 
Starting 
Substrate 
For 
Making 
Oxoloacetate

Question 3

Describe 1st step , enzyme and enzyme regulators

Answer 3

• acetyl-CoA( 2C ) is fused with oxaloacetate to form citrate ( 6C )
• citrate synthetase
• ATP , NADH , citrate , succinly CoA ( inhibitors )
• ADP and NAD+ ( activators )

irreversible

Question 4

Describe 2nd step , enzyme and enzyme regulators

Answer 4

• citrate isomerized into isocitrate

- aconitase

Question 5

Effects of floroacetate ( rat poison )

Answer 5

It acts as acetyl-CoA is converted into florocitrate which binds to and inhibits aconitase stopping ATP synthesis

Question 6

Describe 3rd step , enzyme and enzyme regulators

Answer 6

• isocitrate converted into alpha ketoglycerate ( 5 carbon )
• isocitrate dehydrogenase
• CO2 releases ( de carboxylation)
• NAD+ converted into NADH
• ATP
• ADP and Ca+

Question 7

Describe 4th step , enzyme and enzyme regulators

Answer 7

• a-ketoglycerate is converted into succinly-CoA ( 4 carbon )
• CoA added
• CO2 removed
• NAD+ reduced
• alpha ketoglycerate dehydrogenase
• succinyl CoA , NADH
• Ca

Question 8

What happens if a ketoglycerate DH is defected

Answer 8

-AKG in Converted into 2 hydroxyglucerate which bind to AKG DH and the enzyme won’t make more AKG which are essential for enzyme histone demethylase and DNA not regulated

Question 9

Describe 5th step , enzyme and enzyme regulators

Answer 9

• succinyl-CoA is converted Into succinate
• CoA is removed and the energy used to GDP to GTP followed by ADP to ATP and guanine back to GDP
• succinyl-CoA synthetase

Question 10

Describe substrate level phosphorylation and its diff from oxidative

Answer 10

• this is when ATP is formed by released of energy when Succinly CoA is converted to succinate
• no O2 used
• produces less ATP

Question 11

Describe 6th step , enzyme and enzyme regulators

Answer 11

• succinate converted to fuminate
• succinate dehydrogenase ( complex 2 )
• FAD reduced to FADH2

Question 12

Where is complex 2 Enzyme found and its function

What is phiochromosaitoma

Answer 12

• anchored on cristae
• succinate to fumirate and part of electron transport chain

-altered complex 2 causes tumor at adrenal medulla and causes overproduction of epinephrine by adrenal glands and tachycardia

Question 13

Describe 7th step , enzyme and enzyme regulators

Effects of low 7th step enzyme

Answer 13

• fumirate converted to Malate
• Fumirase

-causes leomas in smooth muscle

Question 14

Describe 8th step , enzyme and enzyme regulators

Answer 14

-Malate converted to oxaloacetate by Malate dehydrogenase

Question 15

Net products of TCA cycle

Answer 15

• 4CO2
• 6 NADH
• 2FADH2
• 2ATP
• 2CoA