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AQA A-Level Biology > Respiration > Flashcards

Flashcards in Respiration Deck (27)
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1
Q

Where does the Electron Transfer chain take place in a cell during respiration?

A

Inner membrane of mitochondria

2
Q

If there is a shortage of oxygen in muscle cells during exercise, some pyruvate is converted into lactate. Explain why muscles become fatigued when insufficient oxygen is available (2)

A
  • increased concentration of lactate lowers pH

- enzymes are inhibited

3
Q

How is anaerobic respiration of glucose in yeast different from anaerobic respiration of glucose in a muscle cell (2)

A
  • ethanol formed by yeast
  • lactate formed by muscle
  • Co2 released by yeast, not in muscle
4
Q

How is anaerobic respiration of glucose in yeast similar to anaerobic respiration of glucose in a muscle cell (2)

A
  • ATP formed
  • pyruvate formed
  • glycolysis takes place
5
Q

Explain why converting pyruvate to ethanol is important in allowing the continued production of ATP in anaerobic respiration (2)

A
  • allows NAD to be recycled

- so that Glycolysis can continue

6
Q

Explain why oxygen is needed for the production of ATP on the cristae of the mitochondria (3)

A
  • ATP formed as electrons pass along transport chain
  • Electrons cannot be passed along the electron transport chain if there’s no O2 to accept them
  • forms H20 from reduced NAD
7
Q

Respiration produces more ATP per molecule of glucose in the presence of oxygen than it does when oxygen is absent. Explain why (2)

A
  • oxygen is the terminal electron acceptor

- oxidative phosphorylation provides most ATP

8
Q

Why was the solution in which the mitochondria suspended isotonic? (1)

A
  • prevent damage to mitochondria caused by osmosis
9
Q

Describe the part played by the inner membrane of the mitochondrion in producing ATP (3)

A
  • Electrons transferred down Electron Transport chain
  • Provides energy to take protons into intermembrane space
  • Energy used to combine ADP and phosphate to produce ATP
10
Q

Explain the advantages of collecting a large number of results (2)

A
  • allows anomalies to be identified

- allows use of statistical test

11
Q

Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis (5)

A
  • In the dark, no ATP production in photosynthesis
  • some tissues unable to photosynthesise
  • ATP cannot be stored
  • Plant uses more ATP than produces in photosynthesis
  • ATP needed for active transport
12
Q

Describe how ATP is made in the mitochondria (6)

A
  • substrate-level phosphorylation
  • krebs cycle produces reduced coenzymes
  • reduced coenzymes release electrons
  • electrons pass through electron transport chain
  • energy is released
  • combines ADP and Pi to form ATP
13
Q

Describe how NAD is regenerated in anaerobic respiration in yeast cells (1)

A

Formed when reduced NAD is used to reduce pyruvate to ethanol

14
Q

Humans synthesise more than their body mass of ATP each day. Explain why it is necessary for them to synthesise such a large amount of ATP (2)

A
  • ATP cannot be stored

- ATP only releases a small amount of energy at a time

15
Q

Give two ways in which the properties of ATP make it a suitable source of energy in biological processes (2)

A
  • Involves a single reaction
  • soluble
  • energy released in small amounts
16
Q

Some of the lactate is oxidised to pyruvate by muscles when they are well-supplied with oxygen. Suggest an advantage of the lactate being oxidised in the muscles (2)

A
  • Lactate is an energy source

- Muscles have increased ATP supply

17
Q

Write a simple equation to show how ATP is synthesised from ADP (1)

A

ADP + Pi –> ATP

18
Q

Human skeletal muscle can respire both anaerobically and aerobically. Describe what happens to pyruvate in anaerobic conditions and explain why anaerobic respiration is advantageous to human skeletal muscle (4)

A
  • forms lactate
  • regenerates NAD
  • allows glycolysis to continue
  • can still release energy when oxygen is in short supply
19
Q

Apart from Respiration, give three uses of ATP in a liver cell (3)

A
  • Active Transport
  • Protein Synthesis
  • Mitosis
20
Q

Describe how acetyl coenzyme A is formed in the link reaction (2)

A
  • oxidation of pyruvate and carbon dioxide is released

- addition of coenzyme A

21
Q

The mitochondria in muscles contain many cristae. Explain the advantage of this (2)

A
  • larger S.A. for the electron carrier system

- provides ATP for contraction

22
Q

Substances which there would be a net movement into the mitochondria

A
  • pyruvate
  • ADP + Pi
  • reduced NAD
  • oxygen
23
Q

Without oxygen, less ATP is produced by respiration. Explain why (2)

A
  • oxygen is the terminal acceptor

- the electron transfer chain cant work

24
Q

Where does Glycolysis occur in a cell during respiration (1)

A

Cytoplasm

25
Q

Which part of the mitochondrion does the Krebs cycle take place?

A

Matrix

26
Q

Describe how acetyl coenzyme A is formed in the link reaction (2)

A
  • pyruvate is oxidised into acetate and loses a CO2 molecule

- acetate combines with coenzyme A to form acetyl coenzyme A

27
Q

Describe what happens to pyruvate in anaerobic conditions and explain why anaerobic respiration is advantageous to human skeletal muscle (4)

A
  • Pyruvate forms lactate using reduced NAD
  • NAD is regenerated
  • Glycolysis can continue
  • to produce more ATP in oxygen is in short supply