respiration

Question 1

describe glycolysis

Answer 1

anaerobic process
occurs in cytoplasm
net yield= 2 ATP
glucose split into 2 3-carbon mol.s

Question 2

what is substrate level photophosphorylation

Answer 2

formation of ATP without electron transport chain

2 used- 4 produced

Question 3

name the 4 main stages of glycolysis

Answer 3

1 phosphorylation

• requires 2 mols of ATP
• 2 phosphates released from ATP attach to glucose mol forming hexose biphosphate

2 lysis

• molecule splits
• forms 2 triose phosphate mol.s

3 phosphorylation

• another phosphate group added to each triose phosphate
• forms 2 triose biphosphate mol.s

4 dehydrogenation and formation of ATP

• 2 triose biphosphate mol.s oxidised by removal of H+ atoms
• atoms accepted by NAD coenzymes forming reduced NAD

Question 4

how does pyruvate enter the mitochondrial matrix

Answer 4

active transport via carrier proteins

Question 5

what is oxidative decarboxylation

Answer 5

removal of carbon and hydrogen from pyruvate
H+ accepted by NAD to form reduced NAD
2-carbon acetyl group binds to coenzyme A forming acetylcoenzymeA

Question 6

describe the Krebs cycle

Answer 6

• produces reduces NAD and FAD which are used in final stages of aerobic respiration to produce ATP by chemiosmosis
• involves processes which release H+ atoms which are picked up by coenzymes NAD + FAD
• occurs in mitochondrial matrix

Question 7

name the 3 stages of the Krebs cycle

Answer 7

1

• acetyl coenzyms A delivers 2-carbon acetyl group to cycle
• combines with 4-carbon oxaloacitate to form 6-carbon citrate

2

• citrate mol. undergoes decarboxylation and dehydrogenation forming 5-carbon compound
• produces 1 reduces NAD and CO2

3
-the 5-carbon compound undergoes further decarboxylation and dehydrogenation eventually regenerating oxaloacitate

Question 8

name 2 coenzymes of respiration

Answer 8

NAD + FAD

Question 9

describe NAD

Answer 9

takes part in all stages
accepts 1 hydrogen
reduced NAD oxidised (loses electron) at start of electron transport chain
results in synthesis of 3 ATP mol.s

Question 10

describe FAD

Answer 10

only accepts hydrogen in Krebs cycle
accepts 2 hydrogens
oxidised further along electrons transport chain
results in synthesis of 2 ATP mol.s

Question 11

what is substrate level phosphorylation

Answer 11

production of ATP without electron transport chain

through transfer of phosphate group

Question 12

describe oxidative phosphorylation

Answer 12

H+ atoms from NAD + FAD delivered to electron transport chains in membranes of cristae in mitochondria