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AQA Biology > 5.2 Respiration > Flashcards

5.2 Respiration Flashcards

1
Q

What is respiration?

A

The process of releasing energy from glucose

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2
Q

What is anaerobic respiration?

A

Process of releasing energy from glucose without the presence of oxygen

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3
Q

What is aerobic respiration?

A

Process of releasing energy from glucose with the presence of oxygen

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4
Q

Name the 4 main stages in aerobic respiration.

A

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

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5
Q

What is the first stage of respiration?

A

Glycolysis

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6
Q

Where does glycolysis occur?

A

Cytoplasm

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7
Q

Outline the stages of glycolysis.

A

Glucose is phosphorylated to glucose phosphate by 2ATP
Glucose phosphate splits into 2TP
2TP is oxidised to 2 pyruvate

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8
Q

What is meant by TP?

A

Triose phosphate

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9
Q

What is meant by ATP?

A

Adenosine TriPhosphate

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10
Q

What is the net gain per glucose of glycolysis?

A

2 ATP
2 reduced NAD

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11
Q

What is produced by glycolysis?

A

Pyruvate

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12
Q

How does pyruvate from glycolysis enter the mitochondria?

A

Via active transport

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13
Q

What is the second stage of respiration?

A

Link reaction

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14
Q

Where does the Link reaction occur?

A

Mitochondrial matrix

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15
Q

Outline the stages of the link reaction.

A

Oxidation of pyruvate to acetate
(Decarboxylation)
(Reduction of NAD)
Acetate combines with coenzyme A to form acetylcoenzyme A

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16
Q

What is the net gain per pyruvate of glycolysis?

A

1 CO₂
2 H

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17
Q

What is produced by the Link reaction?

A

acetyl coenzyme A

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18
Q

Give a summary equation for the link reaction.

A

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

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19
Q

What is the third stage of respiration?

A

Krebs cycle

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20
Q

Where does the Krebs cycle occur?

A

Mitochondrial matrix

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21
Q

What is the Krebs cycle?

A

A series of redox reactions

22
Q

Outline the stages of the Krebs cycle.

A

Acetate released from CoA
Acetate (2C) joins with oxaloacetate forms citrate (6C)
Citrate is decarboxylated & dehydrogenated to 5C compound
5C compound decarboxylated & dehydrogenated to 4C compound
(NAD reduced)
First 4C converted to second 4C
(ATP produced - substrate level phosphorylation)
Second 4C converted to third 4C
Third 4C converted to oxaloacetate

23
Q

What are the products of the Krebs cycle?

A

1 ATP
2 CO₂
3 NADH
1 FADH₂

24
Q

What is the final stage of respiration?

A

Oxidative phosphorylation via ETC

25
What is the Electron Transfer Chain (ETC)?
Series of carrier proteins embedded in membrane of cristae
26
How does ETC produce ATP?
Through oxidative phosphorylation via chemiosmosis during aerobic respiration
27
Outline stages of ETC.
Electrons released from reduced NAD & FAD undergo redox reactions Energy released coupled to maintaining proton gradient or released as heat Oxygen acts as final electron acceptor
28
Where does the electron transport chain occur?
Membrane of cristae
29
How is the proton concentration gradient established during chemiosmosis?
Some energy released from ETC is coupled to active transport of H+ ions (protons) from mitochondrial matrix into intermembrane space
30
How does chemiosmosis produce ATP?
H+ ions (protons) move down concentration gradient from intermembrane space into mitochondrial matrix via channel protein ATP synthase
31
What does ATP synthase do?
Catalyses ADP + Pi -> ATP
32
What is the final electron acceptor in the electron transport chain?
Oxygen
33
What is the role of oxygen in aerobic respiration?
Final electron acceptor in the ETC (Produces water as byproduct)
34
What is the benefit of an ETC instead of single reaction?
Energy is released gradually Less energy released as heat
35
What is chemiosmosis?
Process by which ATP is produced in the mitochondria using the proton gradient established during respiration
36
Name 3 types of molecules that can be used as alternative respiratory substrates.
Proteins Lipids
37
How can lipids act as alternative respiratory substrate?
lipid -> glycerol + fatty acids Phosphorylation of glycerol to TP for glycolysis Fatty acid -> acetate Acetate for link reaction H atoms produced for oxidative phosphorylation
38
How can proteins act as alternative respiratory substrate?
Deamination of amino acids produces: 3C compounds (pyruvate for link reaction) 4/5C compounds (intermediates in Krebs cycle)
38
Name the stages in respiration that produce ATP by substrate-level phosphorylation.
Glycolysis Krebs cycle
39
What is the theoretical yield of ATP per glucose in aerobic respiration?
32 ATP molecules
40
What is the actual yield of ATP per glucose in aerobic respiration?
30-32 ATP molecules.
41
What happens during anaerobic respiration in animals?
Only glycolysis continues using oxidised NAD reduced NAD + pyruvate -> oxidised NAD + lactate
42
What happens to the lactate produced in anaerobic respiration?
Transported to liver via bloodstream Oxidised to pyruvate Used in link reaction in liver cells or converted to glycogen
43
What happens during anaerobic respiration in yeast and plant cells?
Only glycolysis continues Pyruvate is decarboxyated to form ethanal Ethanal reduced to ethanol using reduced NAD to produced oxidised NAD for further glycolysis
44
What is the advantage of producing ethanol/lactate during anaerobic respiration?
Converts reduced NAD back into NAD so glycolysis can continue
45
What is the advantage of producing ethanol during anaerobic respiration?
Ethanol dissolves in cell membrane Cells die when ethanol concentration too high
46
What is the disadvantage of producing lactate during anaerobic respiration?
Acidic so decreases pH Results in muscle fatigue
47
Compare aerobic and anaerobic respiration.
Both involve glycolysis Both require NAD Both produce ATP
48
Contrast aerobic and anaerobic respiration.
Aerobic: substrate-level & oxidative phosphorylation produces more ATP doesn't produce ethanol/lactate Anaerobic: substrate-leve phosphorylation only produces fewer ATP produces ethanol/lactate
49
Suggest how student could investigate the effect of a named varaible on the rate of respiration of a single-celled organism.
Use respirometer Use dye as terminal electron acceptor
50
What is the purpose of sodium hydroxide solution in a respirometer set up?
Absorbs CO₂ so there is a net decrease in pressure as O₂ consumed
51
How could a student calculate the rate of respiration using a respirometer?
Volume of O₂ produced or CO₂ consumed/time x mass of sample Volume = distance moved by coloured drop x π(radius of capillary tube)²

AQA Biology (44 decks)

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