Lecture 17

Where does the TCA cycle occur?

the matrix

Where does the ETC occur?

inner membrane of the mitochondria

What is the coenzyme of pyruvate dehydrogenase?

TPP (Vitamin B1)

What is the coenzyme of Dihydrolipoyl transacetylase?

CoA-SH & lipoic acid

What is the coenzyme of Dihydrolipoyl dehydrogenase?

NAD+ & FAD

What is the purpose of the TCA cycle?

To release the energy stored in the two carbon (acetyl) group via an aeroic pathway by oxidizing two carbon units to CO2 and producing reduced co enzymes.

How many turns of the cycle for every glucose molecule?

two

What steps produce NADH?

3, 4, 8

What steps of the TCA cycle produce FADH2?

6

What steps of the TCA cycle produce CO2?

3 & 4

What steps of the TCA cycle produce ATP?

5

What steps are exergonic and NOT reversible?

3 & 4

What is the enzyme classification for Aconitase?

What is the enzyme classification for Fumarase?

Lyases

What is the enzyme classification for Citrate Synthase?

Lyases

What is the enzyme classification for Succinyl CoA Synthetase?

Ligase

What is the purpose of the ETC?

• couples oxidation of NADH and FADH2

• generates energy to pump protons across a membrane, creating a concentration gradient

What is the purpose of ATP Synthesis?

• Phosphorylation of ADP

• harnesses protons moving back across membrane to drive ATP production

What does complex 1 do? (NADH Q reductase)

(proton pump) NADH enters e- transport chain

What does complex 2 do? (Succinate dehydrogenase)

• FADH2 enters

• not proton pump

• enzyme 6 in TCA cycle

What does CoQ do?

• ubiquinone

• e- carrier

What does complex 3 do?

QH2 reductase (proton pump)

What is the purpose of CytC (cytochrome C)?

• carries e-

What is the purpose of Complex 4?

Cytochrome C oxidase (proton pump) transfers e- to O2 you breathe to produce H2O.

What are the products of NADH & FADH2 + ADP + HPO4 ²-?

ATP + Oxidized coenzymes

What are the products O2 + 4e- + 4H+?

2H2O

How does ATP synthase work?

• does not require chemical energy to produce ATP

• energy for ATP production is derived from the flow of protons throught ATP synthase