Question 18M.2.HL.TZ2.a
| Date | May 2018 | Marks available | [Maximum mark: 8] | Reference code | 18M.2.HL.TZ2.a |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Explain | Question number | a | Adapted from | N/A |
All living organisms depend on a continuous supply of energy.
Explain the stages of aerobic respiration that occur in the mitochondria of eukaryotes.
[8]
a. «cell» respiration is the «controlled» release of energy from organic compounds to produce ATP
b. «cell respiration» involves the oxidation and reduction of electron carriers
c. in link reaction pyruvate is converted into acetyl coenzyme A, CO2 is released and NAD is reduced
d. in the Krebs cycle, a 4 C molecule combines with acetyl CoA
e. decarboxylation releases 2 CO2 molecules for each pyruvate / conversion of 6C to 5C/5C to 4C releases CO2
f. «3» reduced NAD and «1» reduced FAD are produced
g. ATP generated in the Krebs cycle
h. reduced molecules/FAD/NAD are carried to the cristae/inner membrane of the mitochondria
i. transfer of electrons between carriers in the electron transport chain in the membrane of the cristae is coupled to proton pumping
j. protons accumulate in intermembrane space/ between cristae/inner membrane and outer membrane
OR
proton / electrochemical gradient between intermembrane space and matrix is established
k. protons diffuse through ATP synthase to generate ATP
l. chemiosmosis is the use of a proton/electrochemical gradient to generate ATP
m. oxygen is the final electron acceptor
Accept any of the points in a correctly annotated diagram.
