Unit 1: Aerobic respiration (energy released from food) Flashcards
where does the link reaction occur and what are the enzyme/ co-enzymes involved?
occurs in mitochondrial matrix
pyruvate dehydrogenase - assisted by 5 co-factors: lipoic acid/ coA/ NAD/FAD/ TPP
What are the net products of the link reaction?
2 x acetyl coA
2 x NADH
2 x CO2
how is link reaction regulated?
adenylate control of PDC - inhibited by products
where does the krebs cycle occur and what are the net products?
occurs in mitochondrial matrix
6 x NADH
2 x FADH2
2 x GTP
describe the role of two electron shuttles and why are they needed?
needed because inner mitochondrial membrane is impermeable
Glycerol -3 P shuttle: e- enters 2nd complex - mainly found in skeletal muscle - yields 1.5 ATP (simpler/faster)
malate-aspartate shuttle: e- enters 1st complex - mainly found in heart/liver - yields 2.5 ATP (more efficient but more complex)
what type of translocase is powered bythe electron transport chain?
ADP-ATP translocase - saps 25% of gradient because exchange of ATP and ADP requires charge difference created by H+ ions
describe how ETC works
complex 1 accepts electrons from NADH and transfers them to ubiquinone - provides energy for pumping of 4 H+ from matrix to intermembranal space
complex 2 accepts electrons from FADH2 and also transfers to ubiquinone but does not pump h+ ions
complex 3 accepts electrons from ubiquinone and transfers to complex 4 via cytochrome C - pumps 4 H+ ions (2 from matrix/ 2 from ubiquinone)
complex 4 accepts electrons from cytochrome C- pumps 4H+ ions - 2 of which contributes to formation of water
- electrochemical gradient produced leads to production of ATP by ATP synthase
how many ATP produced overall
glycolysis - 2 ATP/ 5 ATP (from 2 NADH)
link reaction - 5 ATP (from 2 NADH)
krebs cycle - 15 ATP (from 6 NADH)/ 3 ATP (2 from FADH2)/ 2 ATP (from 2 GTP)
overall: 32 ATP
How does antimycin work and what is its antidote?
inhibits complex III- no transfer onto cytochrome C
antidote -ascorbic acid
How do cyanide/ carbon monoxide and azide inhibit oxidative metabolism?
inhibits complex IV - no ATP produced
how does oligomycin work and how can it be restored?
inhibits ATP synthase so accumulation of protons - no gradient
- gradient can be restored by DNP - poison moves protons from intermembranal space to matrix
how do plants/ mold toxins affect respiration?
inhibit ADP-ATP translocase