Aerobic Respiration

Question 1

the figure shows the apparatus used for measuring the rate of oxygen consumption in aerobic respiration by seeds.
- for the first ten minutes tap attached to tube A was open and syringe from tube B was removed. Suggest THREE reasons why the apparatus was left for ten minutes

Answer 1

1. to ensure equilibrium is reached
2. allows for the pressure change in the apparatus
3. allows for the respiration of the seeds to stabilise

Question 2

the mitochondria in muscles contain many cristae. Explain the advantage of this

Answer 2

there is a larger surface area for oxidative phosphorylation, to provide the ATP needed for muscle contraction

Question 3

in which part of the mitochondrion does the Krebs cycle take place

Answer 3

the matrix

Question 4

state TWO changes that happen to pyruvate in aerobic respiration

Answer 4

oxidised to form acetate and NAD is reduced to form NADH

Question 5

how does chemiosmosis produce ATP during aerobic respiration

Answer 5

H+ ions (protons) move down their conc gradient from the intermembrane space into the mitochondrial matrix via the channel protein ATP synthase

Question 6

how is a proton concentration gradient established during chemiosmosis in aerobic respiration

Answer 6

some energy released from the ETC is coupled to the active transport of H+ ions (protons) from the mitochondrial matrix into the intermembrane space

Question 7

what happens in the electron transport chain

Answer 7

electrons released from reduced NAD and FAD undergo successive redox reactions these release energy which either maintains the proton gradient or is released as heat energy; oxygen acts as the terminal electron acceptor to produce water

Question 8

listwhat is the electron transport chain (ETC)

Answer 8

a series of carrier proteins embedded in the membrane of the cristae of mitochondria which produces ATP through oxidative phosphorylation via chemiosmosis during aerobic respiration

Question 9

list all the stages of aerobic respiration IN THE CORRECT ORDER

Answer 9

glycolysis, link reaction, krebs cycle, oxidative phosphorylation

Question 10

what happens in the Krebs cycle

Answer 10

there is a series of redox reactions which produces: ATP by substrate-level phosphorylation, the reduced coenzymes FAD and NAD, CO2 from decarboxylation

Question 11

give a summary of the link reaction

Answer 11

pyruvate + NAD + CoA -> acetyl CoA + reduced NAD + CO2

Question 12

what happens during the link reaction

Answer 12

1. the oxidation of pyruvate to acetate per pyruvate molecule - there is a net gain of 1 CO2 and 2H atoms (used to reduce 1 NAD molecule)
2. acetate combines with coenzyme A (CoA) to form acetylcoenzyme A