Question
Oxygen is needed to complete aerobic cell respiration.
a. Explain how chemical energy for use in the cell is generated by electron transport and chemiosmosis. [8]
b. Outline four different functions of membrane proteins. [4]
c. Distinguish between anabolism, catabolism and metabolism. [3]
▶️Answer/Explanation
Markscheme
a. NAD/FAD carries/is reduced by gaining «two» H «atoms»/«two» electrons
b. reduced NAD produced in glycolysis/link reaction/Krebs cycle
c. reduced NAD/FAD delivers electrons/hydrogen «atoms» to ETC
d. ETC is in mitochondrial inner membrane/cristae
e. electrons release energy as they flow along the chain/from carrier to carrier
f. electrons from ETC accepted by oxygen/oxygen is the final electron acceptor
g. proteins in the inner mitochondrial membrane/electron carriers act as proton pumps
h. protons pumped into intermembrane space/proton gradient across inner mitochondrial membrane/proton concentration higher in intermembrane space than in matrix
i. energy «from electrons» used to pump protons into intermembrane space/generate a proton gradient / high H+ concentration is a store of «potential» energy
j. ATP synthase in inner mitochondrial membrane/cristae
k. energy released as protons pass down the gradient/through ATP synthase
l. ATP synthase converts ADP to ATP/phosphorylates ADP
m. oxidative phosphorylation «is ATP production using energy from oxidizing foods»
a. receptor/binding site for hormone/neurotransmitter
b. cell-to-cell communication / cell recognition
c. channels «for passive transport» / facilitated diffusion
d. pumps / active transport
e. cell adhesion
f. «immobilized» enzymes/enzymes embedded in the membrane
g. electron transport / electron carriers
a. metabolism is all enzyme-catalyzed reactions in a cell/organism/is anabolism plus catabolism
b. anabolism is synthesis of polymers/complex/larger molecules/larger substances «from smaller molecules/monomers»
c. catabolism is breaking down «complex» molecules/substances «into simpler/smaller ones/into monomers»