Unit I Biochemistry- Electron Transport and Oxidative Phophorylation
Terms
undefined, object
copy deck
- What is the intracellular location of the electron transport chain?
- Inner mitochonrdrial membrane
- Define oxidation, reduction
-
Oxidation = Lose electrons
Reduction = Gain electrons - What is meant by a half reaction or redox couple?
- Pair of substances, one oxidant (GE) and one reductant (LE)
-
Give the equations for the half and full reactions involving the redox couple
Pyruvate/ Lactate
NAD+/NADH -
Pyr + 2e- + 2H+ -> lactate
NAD+ + H- + H+ -> NADH + H+ - Define the standard reduction potentials Eo and Eo'
-
Eo = Voltage generated when redox couple is in equilibrium with another couple in standard state (1M)
Eo'= Reduction potentials at pH = 7 -
Compute Delta Eo' from the redox potentials for Pyruvate/lactate = -0.19
NAD+/NADH = -0.32. How can you tell from Eo' values whether a redox couple will oxidize or reduce another couple? -
Negative to positive electrons flow
DeltaEo' = Eo'ox - Eo'red
More negative is reductant
-0.19 - (-0.32) = +0.32 - What is the relationship between DeltaGo' and DeltaEo'?
- Delta Go' = -nFDeltaEo'
- Where in the cell do oxidative phophorylation and substrate level phosphorylation to produce ATP occur? Which produces more ATP?
-
oxidative = major manner of producing ATP (inner mitochondrial membrane and matrix)
substrate = minor ATP formation from TCA cycle, occurs in matrix and cytoplasm - How many ATPs are formed from NADH+ + H+ and FADH?
-
NADH = 2.5
FADH2 = 1.5 - Name an uncoupler of oxidative phosphorylation. How does it act? What is its effect on respiration and formation of ATP?
-
2,4 Dinitrophenol, Dicumarol, Fatty acids, Uncoupling Protein
Acts by allowing H+ to flow back into matrix w/o producing ATP. Respiration increases and ATP formation decreases. - Which lipid soluble compound accepts hydrogens from FADH2? What is unique about it?
- Coenzyme Q, is a link btw I, II and III.
- What roles do cytochromes play in respiration? Name the cytochrome complex which reacts with oxygen.
- Cytochromes are electron carriers. Cytochrome oxidase reacts with oxygen.
- What are the four complexes of the electron transport chain? Which are proton pumps?
-
Components:
1)NADH dehydrogenase
2)Succinate dehydrogenase
3)Cytochromes b and c1
4)Cytochrome aa3
I, III, IV pump H+ - What role does ADP play in the regulation of oxidative phosphorylation?
- Exerts resiratory control (utilization of O2)
- Describe the essential features of the chemiosmotic hypothesis? How does it explain 'uncoupling'and the formation of ATP?
- Electrons flow from high to low energy level. Form a proton gradient which then can be used to produce ATP or heat via uncoupling.
- Name the enzyme (also known as complex V) that synthesizes ATP in the electron transport chain.
- ATP synthase
- How does oligomycin affect the generation of ATP in mitochondria?
- Inhibits ATP synthase
- Name an inhibitor of ADP/ATP exchange?
- Atractylocide- Inhibits the carrier which allows passage from mitochondria to cytoplasm