Electron Transport Chain

Question 1

2 types of shuttles

Answer 1

Asparate-Malate shuttle and Glycerophosphate shuttle

Question 2

Asparate-Malate shuttle(s)

Answer 2

Exchanges 1) malate with a-ketoglutarate 2) aspartate with glutamate.
Oxaloacetate can be formed in the cytosol by a transamination of a-keto with aspartate. this can then be transported into the Mito to partake in TCA. Part of Oxaloacetate replenishment.

Question 3

Glycerophosphate shuttle

Answer 3

G3P can transfer its electrons through the cytosolic membrane to form FADH2 in the matrix. Forms DAHP. Adds more electron carriers for the ETC, and also aids in gluconeogenesis/glycolysis.

Question 4

Proton Gradient

Answer 4

Protons on outside of Mito, electrons inside.

Question 5

Electron Carriers

Answer 5

Heme, Ubiquinone, FAD, NAD, and Fe-S.

Question 6

Complex I: Name and Function.

Answer 6

NADH Dehydrogenase. NADH is oxidized, Ubiquinone is reduced and 4 protons are pumped out.

Question 7

Fe-S complex function

Answer 7

They move electrons sequentially around the enzyme, eventually to ubiquinone.
The Sulfur is usually in the form of Cysteine or Inorganic Sulfide.

Question 8

Ubiquinone Form and Function

Answer 8

Resembles an aromatic lipid, with a long chained alkene group to keep anchored in membrane.
Has two carbonyl groups that may become protonated, act as an electron sink.

Question 9

Complex II: Name and Function

Answer 9

Succinate Dehydrogenase. FADH2 becomes oxidized and Ubiquinone is reduced (to ubiquinol). No protons leave. Forms Fumarate and FAD.

Question 10

Complex III: Name and Function

Answer 10

Cytochrome C Reductase. It oxidized ubiquinone to spit out protons or pump electrons to cytochrome c.

Question 11

Complex IV: Name and Function

Answer 11

Cytochrome C Oxidase. Takes 2 electrons from cytochrome c, pumps out 2H and forms two H2O.