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Biology A level > 5.2 Respiration > Flashcards

5.2 Respiration Flashcards

1
Q

What is aerobic respiration?

A

the process of breaking down a respiratory substrate in order to produce ATP using oxygen

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2
Q

What are the 4 stages of aerobic resp?

A
  1. glycolysis
  2. link reaction
  3. kreb’s cycle
  4. the electron transport chain
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3
Q

Where does glycolysis take place?

A

in the cytoplasm of the cell

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4
Q

What stage of aerobic resp is actually classed as anerobic resp?

A

glycolysis

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5
Q

Why is glucose not direclty used in aerobic resp?

A

it would release too much energy for cells which would raise the temp in cells and cells would die

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6
Q

From 1 molecule of glucose how many ATP is produced?

A

38

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7
Q

What type of phosphorylation occurs in glycolysis?

A

substrate-level phosphorylation

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8
Q

What is substrate-level phosphorylation?

A

energy for phosphorylation of ADP is from substrates

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9
Q

What is the process of glycolysis?

A
  1. glucose is phosphorylated by the hydrolysis of 2 ATP = hexose diphosphate produced
  2. hexose diphosphate splits because it is an unstable molecule into 2 triose phosphates
  3. triose phosphate is oxidised (releases hydrogen) - dehydrogenase enzymes involved
    this is an exergonic reaction = releases energy to synthesis ATP
  4. pi from triose phosphate is used to synthesis ATP and pyruvate (3C) is produced
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10
Q

Wha is the NET gain of products from 1 glucose molecule in glycolysis?

A

2 ATP
2 pyruvate
2 NADH2

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11
Q

What type of reaction happens between the hydrolysis of ATP and the phosphorylation of glucose?

A

a simultaneous reaction

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12
Q

What are simultaneous reactions?

A

2 reactions that happen at the same time that rely on each other for the transfer of a product

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13
Q

Where does the link reaction happen?

A

in the mitochondria matrix

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14
Q

What is the process of the link reaction?

A
  1. pyruvate is decarboxylated = releases CO2, decarboxylase enzymes involved
  2. pyruvate is oxidised by dehydrogenase enzymes - at the same time, NAD is reduced
  3. acetate is produced
  4. Co-enzyme A reacts with acetate to form Acetyl Co-enzyme A which is carried to the kreb’s cycle
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15
Q

Wha are the net gains for 1 glucose in the link reaction?

A

2 acetyle Co-enzyme A
2 CO2
2 NADH

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16
Q

How times does the link reaction happen per 1 molecule of glucose?

A

x2 = 2 pyruvates are produced from 1 glucose in glycolysis

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17
Q

Where does the Kreb’s cycle happen?

A

the mitochondrial matrix

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18
Q

Why is glucose phosphorylated?

A

makes it more reactive and activated

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19
Q

What type of phosphorylation happens in the kerb’s cycle?

A

substrate-level phosphorylation

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20
Q

What is the process of the Krebs cycle?

A
  1. Co-enzyme A brings acetate to the cycle, acetate reacts with a 4C compound
  2. this 6C compound is oxidised to release H to reduce NAD—> NADH
  3. the 6C compound is also decarboxylated and releases CO2 producing a 5C compound
  4. the 5C compound is decarboxylated and releases CO2
  5. 5C compound is oxidised to release 6H
  6. 2 NAD are reduced by the 5C compound
  7. FAD is also reduced
  8. reduction of FAD releases enough energy for the synthesis of ATP = substrate-level phosphorylation
  9. the 4C compund is regenerated
21
Q

What is the net gain from 1 molecule of glucose from the krebs cycle?

A

4 CO2
6 NADH
2 ATP
2 FADH

22
Q

How many times does the Krebs cycle happen per 1 glucose molecule?

A

x2 = 2 acetyl Co-Enzyme A are produced in the link reaction

23
Q

Is Co-enzyme A an enzyme?

A

NO

24
Q

How does pyruvate get into the mitochondrial matrix from the cytoplasm of the cell?

A

by facilitated diffusion because the mitochondrial membrane has specific carrier proteins for pyruvate

25
Q

Why does glycolysis need to take place?

A

glucose cannot cross the mitochondiral membrane - glycolysis takes place to produce pyruvate which can cross the membrane

26
Q

Why cant glucose cross the mitochondrial membrane?

A

the membrane has no specific carrier proteins for glucose

27
Q

Where does oxidative phosphorylation take place?

A

the mitochondrial cisternae

28
Q

What is oxidative phosphorylation?

A

energy for the phosphorylation of ADP comes from an oxidation reaction

29
Q

Describe the process of oxidative phosphorylation

A
  1. NADH2 is oxidised and H2 is removed, NAD does back to the other reactions
  2. H2 atoms dissociates into 2H+ and 2e-
  3. relatively high energy e- goes to an e- carrier this gives enough energy for a proton pump to actively pump 2H+ into the inner membrane space
  4. there is an increase in conc of H+ in the inner membrane space = conc grad for facilitated diff through a stalkd particle containing ATP synthase
  5. facilitated diff of H+ releases enough electrical potential energy to synthesis ATP
  6. the remaining e- and H+ associate to form H2 again
  7. O2 reacts with the H2 as the final electron acceptor to form water - O2 is reduced
30
Q

What is oxidised in oxidative phosphorylation?

A

the H carriers = NADH2 and FADH2

31
Q

What is the stalked particles role in oxidative phosphorylation?

A

in the cell-surface membrane on the matrix = contains ATP synthase

32
Q

What is reduced in oxidative phosphorylation?

A

O2

33
Q

What do you have at the start of oxidative phosphorylation?

A

4 ATP
10 NADH2
2 FADH2

34
Q

How many molecules of ATP is produced from 1 molecule of NADH2 and why?

A

1 NADH2 activates 3 proton pumps - 6H+ are being pumped = 3 ATP

35
Q

How many ATP are produced from 1 molecule of FADH2 and why?

A

1 FADH2 activates 2 proton pumps - 4H+ being pumped = 2 ATP

36
Q

Why does the oxidation of FADH2 only activate 2 proton pumps?

A

the e- released from the oxidation of FADH2 and dissociation of H2 do not have as higher energy so they are accepted by a lower energy level e- acceptor further along the membrane

37
Q

Why might cells not actually produce 38 ATP molecules from the oxidation of 1 glucose molecule?

A

used as energy to:
- transport pyruvate
-transport H carriers
-active transport to pump protons

38
Q

In a respirometer why would the coloured liquid move down the scale?

A

organism is aerobically respiring so they take in O2
Co2 is produced but is absorbed by potassium hydroxide
vol of gases in the tube decreases and pressure also decreases

39
Q

What is anaerobic respiration?

A

respiration that occurs when there is no oxygen present

40
Q

What are obligate anerobes?

A

orgs that only resp anaerobically as O2 inhibits resp

41
Q

What are facultative anaerobes?

A

can anaerobically respire to survive when needed for short periods of time

42
Q

Why can only glycolysis take place in anaerobic respiration?

A

no O2 = no final electron carrier = no e- transport chain
so there is no oxidation of H carriers so they cannot be returned to other reactions

43
Q

How many molecules of ATP are produced per 1 glucose in anerobic resp?

A

2 ATP per 1 glucose

44
Q

What is the process of anaerobic resp in animals?

A
  1. glucose is phosphorylated by 2ATP –> 2ADP
  2. hexose diphosphate is made
  3. hexose diphosphate breaks down into 2x triose phosphates
  4. 2 NAD are reduced and 4ATP molecules are synthesised
  5. 2x pyruvate are formed
  6. 2 NADH are oxidised to 2NAD
  7. 2x lactate is formed
45
Q

What is the process of anaerobic resp in plants and fungi?

A
  1. glucose is phosphorylated by 2ATP –> 2ADP
  2. hexose diphosphate is made
  3. 2 NAD are reduced –> 2NADH and 4 ATP molecules are made from hexose diphosphate being oxidised
  4. x2 pyruvate are formed
  5. pyruvate is decarboxylated and 2NADH are oxidised –> 2NAD
  6. x2 ethanal is produced
  7. x2 ethanol is produced when aerobically respiring
46
Q

What are are 2 alternative respiratory substrates?

A

proteins and lipids

47
Q

How is the glycerol of lipids used as a respiratory substrate?

A
  1. glycerol is hydrolysed
  2. produces 3C sugar - phosphorylised
  3. triose phosphate formed
  4. pyruvate is made to enter the link reaction, krebs cycle and oxidative phosphorylation
48
Q

How are the fatty acid chains of lipids used as a resp substrate?

A
  1. long fatty acid chains are split into 2C fragments
  2. these produce Acetyl Co-enzyme A
  3. can enter aerobic resp = Kreb’s –> oxidative phos
49
Q

How are proteins used as a resp substrate?

A
  1. NH3 removed in deamination
  2. remaining is an organic acid which can enter the Kreb’s cycle

Biology A level (33 decks)

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