Week 4 Carbs Cont

Question 1

Biosynthesis of ATP

Answer 1

Substrate-level phosphorylation
-Does not require oxygen
-Small contribution to total ATP

Oxidative phosphorylation
-Requires Oxygen
-Involves respiratory chain (electron transfer)
-Main contribution to total ATP

Question 2

Oxidative phosphorylation

Answer 2

Two coupled processes

Electron transport
-Transport of e- through respiratory chain
-Achieved by redox reactions
-Formation of H2O

Phosphorylation
-Formation of ATP by ATP synthetase
-Achieved by proton gradients across membrane

Question 3

Electron-transport chain

Answer 3

Each complex contains multiple redox centers consisting of:

-Flavin Mononucleotide (FMN) or Flavin Adenine Dinucleotide (FAD)
•Initial electron acceptors for Complex I and Complex II
•Can carry two electrons by transferring one at a time

»Cytochromes a, b or c

»Iron-sulfur cluster

Question 4

Overview of ETC & OP

Question 5

Cytochromes

Answer 5

One electron carriers
»Iron coordinating porphoryin ring derivatives
»a, b or c differ by ring additions

Question 6

CoEnzyme Q (or Ubiquinone)

Answer 6

Ubiquinone is a lipid-soluble compound that readily accepts electrons
»Upon accepting two electrons, it picks up two protons to give an alcohol, ubiquinol
»Ubiquinol can freely diffuse in the membrane, carrying electrons with protons

»Coenzyme Q is a mobile electron carrier transporting electrons from Complexes I and II to Complex III

Question 7

Takeaway

Answer 7

Oxidative phosphorylation is the main way ATP is recycled
»Oxidative phosphorylation = 2 processes couple together
•Electron transport
•ATP synthesis

»NADH and FADH deliver electrons to the electron transport chain

»ETC Involves 4 complexes (I, II, III, IV) that sit on the inner mitochondrial membrane)
•Cytochromes, CoQ, Fe and FMN

»ETC = chain of REDOX reactions, ultimately combining e- and H+ with O2 to form H2O

Question 8

Biosynthesis of ATP

Answer 8

Substrate-level phosphorylation
»Does not require oxygen
»Small contribution to total ATP

Oxidative phosphorylation
»Requires Oxygen
»Involves respiratory chain (electron transfer)
»Main contribution to total ATP

Question 9

Oxidative phosphorylation

Answer 9

Two coupled processes

Electron transport
»Transport of e- through respiratory chain
»Achieved by redox reactions
»Formation of H2O

Phosphorylation
»Formation of ATP by ATP synthetase
»Achieved by proton gradients across membrane

Question 10

Chemiosmotic theory

Answer 10

Intact inner mitochondrial membrane is required (to maintain a proton gradient).

Protons are lumped across this membrane as electrons flow through the respiratory chain.