Respiration Flashcards

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1
Q

examples of transporting substances across membranes

A

active transport using sodium-potassium pump in cell membrane

exocytosis of digested bacteria from WBC

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1
Q

state 4 reasons why we need respiration

A

transporting substances across membranes

anabolic reactions

movement

maintaining body temp

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2
Q

examples of anabolic reactions

A

synthesis of DNA from nucleotides

synthesis of proteins from amino acids

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3
Q

examples of movement

A

cellular movement of chromosomes via spindle

mechanical contraction of muscles

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4
Q

what are the stages of aerobic respiration

A

glycolysis

link reaction

krebs cycle

oxidative phosphorylation

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5
Q

how large are the mitochondria

A

0.5 – 1 micrometres in diameter

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6
Q

describe the structure of a mitochondria

A

two phospholipid bilayers - outer + inner membrane

intermembrane space

matrix

cristae

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7
Q

what is cristae

A

projections of the inner membrane that increase the surface area for oxidative phosphorylation

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8
Q

describe the inner mitochondrial membrane

A

Folded (cristae)
- large surface area – membrane hold many chains / enzymes

Less permeable

Site of electron transport chain

Location of ATP synthase enzymes

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9
Q

describe the outer mitochondrial membrane

A

Smooth

Permeable to some small molecules

compartmentalisation

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10
Q

describe the inter-membrane space

A

proteins pumped into this space by electron transport chain

Has low pH – high conc of protons

Conc gradient across inner membrane form during oxidative phosphorylation – essential for ATP synthesis

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11
Q

describe the matrix

A

Aqueous solution in inner membranes of mitochondrion

Has ribosomes / enzymes / circular mitochondrial DNA

enzymes for krebs cycle + links reaction

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12
Q

label this

A
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13
Q

overall description of glycolysis

A

phosphorylation + splitting of glucose

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14
Q

overall description of link reaction

A

decarboxylation + dehydrogenation of pyruvate

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15
Q

overall description of krebs cycle

A

cyclical pathways with enzyme-controlled reactions

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16
Q

overall description of oxidative phosphorylation

A

production of ATP through oxidation of hydrogen atoms

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17
Q

where does glycolysis occur

A

cell cytoplasm

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18
Q

where does link reaction occur

A

matrix of mitochondria

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19
Q

where does krebs cycle occur

A

matrix of mitochondria

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20
Q

where does oxidative phosphorylation occur

A

inner membrane of mitochondria

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21
Q

what are the 4 stages of glycolysis

A

phosphorylation

lysis

oxidation

dephosphorylation

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22
Q

what happens in phosphorylation - glycolysis

A

Glucose phosphorylated by 2 ATP

Forms fructose / hexose bisphosphate – 6C

Glucose + 2ATP → Fructose bisphosphate

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23
Q

what happens in lysis - glycolysis

A

Fructose bisphosphate splits into two molecules of triose phosphate 3C

Another phosphate group added to each one – 2 triose bisphosphate

Fructose bisphosphate → 2 Triose phosphate

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24
Q

what happens in oxidation - glycolysis

A

Hydrogen removed from each molecule of triose phosphate + transferred to coenzyme NAD - triose phosphate is oxidised

Forms 2 molecules of reduced NAD

4H + 2NAD → 2NADH + 2H+

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25
Q

what happens in dephosphorylation - glycolysis

A

Phosphates transferred from intermediate substrate molecules

Forms 4 ATP through substrate – linked phosphorylation

Forms 2 pyruvate molecules 3C

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26
Q

describe glycolysis in full

A
  • Phosphorylation

Glucose phosphorylated by 2 ATP

Forms fructose / hexose bisphosphate – 6C

Glucose + 2ATP → Fructose bisphosphate

  • Lysis

Fructose bisphosphate splits into two molecules of triose phosphate 3C

Another phosphate group added to each one – 2 triose bisphosphate

Fructose bisphosphate → 2 Triose phosphate

  • Oxidation

Hydrogen removed from each molecule of triose phosphate + transferred to coenzyme NAD - triose phosphate is oxidised

Forms 2 molecules of reduced NAD

4H + 2NAD → 2NADH + 2H+

  • Dephosphorylation

Phosphates transferred from intermediate substrate molecules

Forms 4 ATP through substrate – linked phosphorylation

Forms 2 pyruvate molecules 3C

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27
Q

what are the end products per glucose molecule of glycolysis

A

2 pyruvate molecules

Net gain of 2 ATP

2 reduced NAD

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28
Q

draw out glycolysis in a diagram

A
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29
Q

what type of reaction is glycolysis

A

anaerobic

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30
Q

what is the link reaction also known as

A

oxidative decarboxylation

31
Q

what type of reaction is the link reaction

A

aerobic

32
Q

describe the link reaction in full

A

(2) Pyruvate enters mitochondrial matrix via active transport

Carbon dioxide is removed

Hydrogen removed – oxidative decarboxylation

Hydrogens accepted by NAD – form NADH

The 2C acetyl group is bound by coenzyme a forming acetylcoenzyme A (acetyl CoA)

Acetyle CoA delivers acetyl group to krebs cycle

33
Q

put the link reaction into a digram

A
34
Q

what is CoA

A

Consists of nucleoside (ribose + adenine ) + a vitamin

35
Q

what are the end products of the link reaction per glucose molecule

A

2 Acetyl CoA molecules

2 Carbon dioxide molecules

2 Reduced NAD molecules

36
Q

describe the krebs cycle

A

Acetyl CoA delivers acetyl group to krebs cycle

2C acetyl group combines with 4C oxaloacetate to form 6C citrate

Citrate molecule undergoes decarboxylation + dehydrogenation and is reverted back to oxaloacetate via redox reactions

37
Q

more specifically - describe the regeneration of oxaloacerate

A
  • Decarboxylation of citrate

Releases 2 molecules of carbon dioxide as waste gas

  • Oxidation / dehydrogenation of citrate

Releases H atoms that reduce coenzyme NAD and FAD

8H + 3NAD + FAD → 3NADH + 3H+ + FADH2

  • Substrate – level phosphorylation

Phosphate transferred from intermediate to ADP
Forms 1 ATP

38
Q

draw out the krebs cycle

A
39
Q

what are the end products of the krebs cycle per gluclose molecule

A

4 molecules of carbon dioxide

6 NADH molecules

2 FADH molecules

2 ATP molecules

40
Q

conenzymes in respiration

A

CoA

NAD

FAD

41
Q

importance of CoA

A

CoA binds to acetyl group (2C) + forms acetyl CoA

Supplied acetyl group to krebs cycle

42
Q

importance of NAD / FAD

A

Transfer the hydrogen atoms they got when they were reduced to the electron transport chain on inner mitochondrial membrane

43
Q

how much reduced NAD is formed throughout respiration and where from

A

2 x 1 = 2 from Glycolysis

2 x 1 = 2 from the Link Reaction

2 x 3 = 6 from the Krebs cycle

44
Q

how much reduced FAD is formed throughout respiration and where from

A

2 x 1 = 2 from the Krebs cycle

45
Q

what is the model of oxidative phosphorylation

A

chemiosmotic theory

46
Q

describe the full process of oxidative phosphorylation

A

Hydrogen atoms donated by NADH + reduced FAD

Hydrogen atoms split into H+ and electrons

High energy electrons enter electron transport chain

Release energy as they move through

Released energy used to actively transport protons across inner mitochondrial membrane = from matrix into intermembrane space

Conc gradient established

Protons return to matrix via facilitated diffusion – through channel protein ATP synthase

movement of protons down conc gradient provides energy for ATP synthesis

oxygen – final electron acceptor

combines with protons + electrons at end of transport chain to form water

47
Q

describe the electron transport chain

A

Made up of series of membrane proteins / electron carriers

Positioned close together

48
Q

why are the H+ needed to be actively transported across the membrane

A

Inner membrane impermeable to H ions so electrons carriers are needed to pump proton

49
Q

what membrane are these protons being pumped across

A

from matrix into intermembrane space

across inner membrane

50
Q

talk through this diagram

A
51
Q

what are the consequences of lack of oxygen

A

no final acceptor of electrons

electron transport chain stops functioning

No more ATP is produced via oxidative phosphorylation

Reduced NAD and FAD aren’t oxidised by an electron carrier

No oxidised NAD and FAD are available for dehydrogenation in the Krebs cycle

Krebs cycle stops

52
Q

what are Obligate anaerobe

A

can’t survive in oxygen – prokaryotes

53
Q

what are Facultative anaerobes

A

synthesis ATP by aerobic respiration if oxygen is present but can switch to anaerobic in absence – yeast

54
Q

what are obligate aerobe

A

only make ATP in presence of oxygen

organism as a whole

55
Q

what is fermentation

A

process by which complex organic compounds are broken down into simpler inorganic compounds without oxygen or electron transport chain

56
Q

how is ATP produced in fermentation

A

by substrate-level phosphorylation

Production of ATP with transfer of phosphate group from short-lived, highly reactive intermediate – creatinine phosphate

57
Q

what is alcoholic fermentation

A

Pyruvate converted to ethanal

(Catalysed by pyruvate decarboxylase)

Ethanal then accept hydrogen atom from reduced NAD – ethanol

Regenerated NAD – enzyme + glycolysis occurs

58
Q

why is less ATP produced in fermentation than aerobic respiration

A

glucose not fully broken down

59
Q

what type of reaction is alcoholic fermentation

A

Irreversible + can continue indefinitely

60
Q

disadvantages of alcoholic fermentation

A
  • less ATP produced
  • ethanol - toxic to yeast
61
Q

how does lactate fermentation work

A

Pyruvate – act as hydrogen acceptor - takes hydrogen from reduced NAD

(Catalysed by lactate dehydrogenase)

Pyruvate then converted into lactate

NAD regenerated

Glycolysis can continue

62
Q

where does lactate fermentation occur

A

in mammals

63
Q

disadvantages of lactate fermentation

A

Cannot occur indefinitely

Reduced quality of ATP produced not enough to maintain metabolic process

Accumulation of lactic acid – reduced pH – proteins denaturing

Respiratory enzymes + muscle filaments will cease to function at low pH

64
Q

what catalyses lactate fermentation

A

lactate dehydrogenase

65
Q

what catalyses alcoholic fermentation

A

pyruvate decarboxylase

66
Q

compare aerobic + anaerobic respiration

stages
oxidation of glucose
total ATP produced
location
products

A
67
Q

examples of respiratory substrates

A

Glucose
Other carbohydrates
Lipids
Proteins

(Only respired aerobically when all other substrates used up // Structural + functional roles )

68
Q

which respiratory substrate has the greatest + lowest energy values

A
69
Q

why is there a difference in energy values

A

Substrate molecule broken down + hydrogen atoms available

Hydrogen carrier molecules – NAD / FAD – gain these hydrogens

transfer them to the inner mitochondrial membrane

reduced NAD + FAD release hydrogen atoms - split into protons + electrons

protons pumped across inner mitochondrial membrane into intermembrane space

proton gradient – chemiosmosis – ATP production

protons oxidised to form water

molecules with higher hydrogen content – greater proton gradient + form MORE ATP

70
Q

why does lipids have the greatest energy value

A

fatty acids in lipids – long hydrocarbon chain – lots of hydrogen atoms

71
Q

what can pyruvate be used for

A
72
Q

what is the formula for the respiratory quotient

A
73
Q

what will cause different RQ values

A

different number of carbon-hydrogen bonds

more carbon-hydrogen bonds means more hydrogen atoms in proton gradient

more ATP produced

more oxygen therefore needed to breakdown molecule

74
Q

RQ value of glucose + why

A

glucose – equal amount of carbon dioxide + oxygen

RQ value of 1

75
Q

what substrate has the lowest RQ value

A

lipids

76
Q

why is respiration not entirely efficient

A

some H+ leak back into matrix