aerobic respiration

Question 1

what is the purpose of aerobic respiration ?

Answer 1

produces ATP which can be hydrolysed to ADP and Pi
to release energy for metabolic reaction/ phosphorylate compounds to make them more reactive

Question 2

name the 4 stage of aerobic respiration and where they occur

Answer 2

glycolysis - cytoplasm
link reaction - mitochondrial matric
krebs cycle - mitochondrial matric oxidative phosphorylation - cristae

Question 3

outline the stages of glycolysis

Answer 3

1. glucose is phosphorylated to glucose phosphate by 2 x ATP
2. glucose phosphate splits into 2 x triose phosphate
3. they are than oxidised to 2x pyruvate
   net gain of 2x reduced NAD and 2 x ATP per glucose

Question 4

what are the products in glycolysis ?

Answer 4

2x pyruvate
4x NADH
2 ATP

Question 5

how does pyruvate from glycolysis enter the mitochondria ?

Answer 5

active transport

Question 6

what happens in the link reaction ?

Answer 6

1. complete oxidation of pyruvate to acetate per pyruvate molecule: net gain 1x CO2 ( decarboxylation) and 2H atoms ( used to reduce 1xNAD )
2. acetate combines with coenzyme A (CoA) to form acetylcoenzyme A

Question 7

what are the products of the link reaction ?

Answer 7

2x acetylCoA
2x NADH
2x CO2

Question 8

give a summary equation for the link reaction

Answer 8

pyruvate + NAD + CoA
——->
acetylCoA + reduced NAD + CO2

Question 9

what happens in the Krebs cycle ?

Answer 9

series of redox reaction produces:
ATP by substrate level phosphorylation
reduced coenzyme e.g. NADH
CO2 from decarboxylation

Question 10

what happens in the Krebs cycle ?

Answer 10

1. acetyl CoA is added to the four carbon oxaloacetate to form six carbon citrate using citrate synthase
2. acetyl coenzyme A - Goes back to the link reaction

Question 11

what are the products of the kerbs cycle ?

Answer 11

for glucose: x4CO2 x2FADH x2ATP x6NADH
for cycle: x2CO2 x3NAD x1 ADP FAD

Question 12

what is the electron transport chain ?

Answer 12

a series of carrier proteins embedded in membrane of the cristae of mitochondria

Question 13

name the process that the electron transfer chain used to produce ATP in aerobic respiration

Answer 13

oxidative phosphorylation via chemiosmosis

Question 14

what happens in the electron transfer chain ?

Answer 14

electrons released from NAD and FAD undergo successive redox reactions
the energy released is coupled maintaining proton gradient or released as hear
oxygen acts as final electron acceptor

Question 15

how is a proton conc gradient established during chemiosmosis in aerobic respiration ?

Answer 15

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

Question 15

how does chemiosmosis produce ATP during aerobic respiration ?

Answer 15

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

Question 16

state the role of oxygen in aerobic respiration ?

Answer 16

final electron acceptor in electron transfer chain

Question 17

what is the benefit of an electron transfer chain rather than a single reaction ?

Answer 17

energy is released gradually
less energy is released as heat