etc and oxphos

Question 1

describe the structure of mitochondria

Answer 1

2 membranes and a matrix

outer membrane= permeable to small molecules/ions

inner membrane= impermeable to small molecules

Question 2

what does the inner membrane of mitochondria contain

Answer 2

folds called cristae, components of etc, ATP synthase to generate ATP from H+ gradient across inner membrane, the folds increase surface area for ETC

Question 3

what does the mitochondria matrix contain

Answer 3

citric acid enzymes, DNA, ribosomes, beta oxidation enzymes, PDH complex

Question 4

describe what happens in etc oxphos steps

Answer 4

energy rich molecules like glucose an amino acids get converted into CO2 and water in a series of oxidative reactions, the metabolic intermediates donate electrons to NAD+ and FAD+ to make NADH and FADH, NADH/FADH donate e- to etc and the energy is used to move protons across inner mitochondrial membrane (IMM) to make a proton gradient, the gradient drives the formation of ATP from ADP and Pi

Question 5

what is coenzyme Q and what happens when 1 or 2 electrons are added

Answer 5

ubiquinone, a lipid soluble molecule with a long isoprenoid side chain, diffusible in the membrane

+1e-= .QH (radical), semiquinone
+2e-= QH2, uniquinol

Question 6

describe the 4 etc reactions

Answer 6

complex 1- NADH dehydrogenase= uses NADH to transfer electrons to complex Q to make QH2, pumps 4 protons across IMM

complex 2- succinate dehydrogenase= transfers an electron to Q to make QH using FADH

complex 3 - cytochrome bc 1 complex= QH2 transfers electrons to cytochrome c, pumps 4 protons across, oxygen reduced to water

complex 4 - cytochrome oxidase= transfers electrons to oxygen, pumps 2 protons across IMM