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LGS A-Level OCR Biology > Unit 5 - Respiration > Flashcards

Unit 5 - Respiration Flashcards

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1
Q

Respiration

A

Process by which energy stored in complex organic molecules is released and immediately transferred to ATP
Energy is released through hydrolysis (making new bonds)

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2
Q

Why do animals need energy

A 
Active transport 
Endo/exocytosis
Synthesis of protein
DNA replication 
Cell division 
Movement 
Activation of a chemical (phosphorylation)
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3
Q

Catabolic

A

Releasing energy

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4
Q

Anabolic

A

Energy consuming

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5
Q

ATP

A

Intermediary between catabolic and anabolic reactions
Relatively stable, only broken down by hydrolysis by enzyme catalysis (energy released can be controlled)
Easily moved around a cell when in solution

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6
Q

Hydrolysis of ATP

A

Catalysed by ATPase
ATP is hydrolysed to produce ADP then again to produce AMP
ATP –> ADP (-30.5), ADP –> AMP (-30.5), AMP —> A (-13.8)

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7
Q

Structure of ATP

A

Ribose attached to adenine (phosphodiester bond)
3 inorganic phosphate groups
Phosphorylated nucleotide

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8
Q

Processes in aerobic respiration

A

Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation

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9
Q

Glycolysis

A

Occurs in cytoplasm
Phosphorylation —> hexose biphosphate (2 phosphate groups from 2 ATP)
Hexose biphosphate splits into two
Oxidation (removal of H atoms) - accepted by NAD to make NADH
Breaks down glucose into pyruvate (3C), 2 NADH and 2 ATP

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10
Q

Where does glycolysis occurs

A

Cytoplasm

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11
Q

Why are ATP used in the first stage of glycolysis

A

Provide activation energy

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12
Q

Where does oxidative phosphorylation occur

A

Cristae

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13
Q

Role of ATP in the cell

A

Universal currency of energy
Phosphates can be removed by hydrolysis to release 30 kJ/mol energy
Energy used in metabolic reactions
Energy released in small quantities to prevent cell damage

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14
Q

Where does the Kreb’s cycle occur

A

Matrix of mitochondria

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15
Q

Coenzymes in leaf

A

NAD and FAD can be reduced to NADH and FADH2 and act as hydrogen carriers
NADPH reduces molecules by adding e-
ATP phosphorylates
Coenzyme A carries acetate to Kreb’s cycle

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16
Q

Link reaction

A

Pyruvate is decarboxylated to acetate (+ CO2)
Combines w/ CoA to make acetyl coenzyme A
Happens twice for glycolysis
Produces 2 NADH

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17
Q

Kreb’s cycle

A

CoA is recycled back to link reaction
Acetate combines with oxaloacetate to make citrate
Decarboxylated 2x to give orig. 4C compound, oxaloacetate
Produces 6 NADH, 2 FADH2 , 2 ATP and 4 CO2 (substrate level phosphorylation)

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18
Q

Which cofactor is part of the ETC

A

Fe^2+

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19
Q

What’s found in the matrix

A 
Enzymes 
NAD
FAD
Oxaloacetate 
Mitochondrial DNA
Mitochondrial ribosomes
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20
Q

Mitochondrial DNA

A

Codes for mitochondrial enzymes and other proteins

21
Q

Mitochondrial ribosomes

A

Where proteins are assembled

22
Q

Where can fatty acids be used in respiration

A

Fatty acids can produce acetate and enter the Kreb’s cycle directly

23
Q

Where can glycerol be used in respiration

A

Can be converted to pyruvate and enter the link reaction

24
Q

Where does the link reaction occur

A

Matrix of mitochondrion

25
Q

Theoretical yield of ATP from 10 NADH

A

25

26
Q

Total theoretical yield of ATP per pyruvate

A

25 - NADH
2 - FADH2
1 - Krebs cycle
2 - glycolysis

=30

27
Q

Why is the yield of ATP not 100%

A

ATP has to be used for active transport of pyruvate and NADH

28
Q

RQ

A

Vol. of CO2/ Vol. of O2 per unit time

29
Q

RQ value for glucose

A

1

30
Q

RQ value for amino acids

A

0.8/0.9

31
Q

RQ value for triglycerides

A

0.7

32
Q

Investigating respiration rates of yeast

A

Put a known vol. and conc. of a substrate sol. into a tt
Add a known vol. of buffer soln. - keep pH constant
Place tt in water bath (25 degrees)
Add known mass of dry yeast
After yeast has dissolved, place a bung on the tt which is attached to a gas syringe (should be set to 0)
Start the stopwatch
Record vol. of CO2 produced at regular intervals and calculate rate

33
Q

Using a respirometer to measure O2 consumption

A

Set up respirometer - one w/ glass beads and the other w/ woodlice of same vol.
Add KOH to both - absorbs CO2 produced
Use syringe to set fluid in manometer to known level
Measure distance travelled by liquid in manometer - gives you vol. of O2 used up (pi r^2 h - need diameter of capillary tube)

34
Q

Why does the liquid move in the manometer

A

As the organisms use up the O2, the pressure decreases causing coloured liquid in manometer to move.

35
Q

Limitation of using respirometer

A

Difficult to accurately read the meniscus of the fluid in the manometer

36
Q

Substrate level phosphorylation

A

ATP is formed by the direct transfer of Pi to ADP

Only occurs in Glycolysis and Kreb’s cycle

37
Q

Substrate level phosphorylation in glycolysis

A

2 ATP per each glucose, when Trios-biphosphate is converted to pyruvate

4 - 2 = 2

38
Q

Substrate level phsophorylation in Kreb’s cycle

A

1 per each turn

Occurs when 5C compound is converted to oxaloacetate

39
Q

NAD vs FAD

A

NAD used in all stages but FAD only in Kreb’s
NAD accepts 1 H, FAD accepts 2 H’s
NADH is oxidised at the start of the etc releasing e- and H+ while FADH2 is oxidised further along the chain
NADH synthesises 3 ATP but FADH2 synthesises 2 ATP

40
Q

Oxidative phosphorylation

A

FADH2 and NADH deliver H to etc in cristae
H dissociates into H+ and e- (used in synthesis of ATP through chemiosmosis)
Energy is released as e- travel down etc, creates a proton gradient
At end of etc, e- combines w/ H+ and O2 –> water
Etc cannot operate w/out oxygen

41
Q

Obligate anaerobes

A

Cannot survive on the presence of oxygen at all

42
Q

Facultative anaerobes

A

Synthesie ATP by aerobic respiration if oxygen is present but can switch to anerobic e.g. yeast

43
Q

Obligate aerobes

A

Can only synthesise ATP in the presence of oxygen e.g. mammals

44
Q

Fermentation

A

Produces ATP through substrate level phosphorylation only, no involvement of electron transport chain

45
Q

Alcoholic fermentation

A

Occurs in yeast and some root cells
Glycolysis occurs and pyruvate is decarboxylated to ethanal
Ethanal accepts H+ from NADH to produce ethanol and NAD (recycled)
Produces ethanol and CO2

46
Q

Lactate fermentation

A

Carried out in animal cells and produces lactate
Glycolysis occurs as normal
Lactate dehydrogenase causes pyruvate to accept H from NADH and is converted to lactate and NAD (recycled)
Allows glycolysis to keep occurring

47
Q

Where is lactic acid converted back to glucose

A

Liver but requires oxygen –> oxygen debt after exercise

48
Q

Why can lactate fermentation not occur indefinitely

A

Reduced ATP isn’t enough to sustain vital processes

Accumulation of lactic acid leads to fall in pH, proteins denature (respiratory enzymes)

LGS A-Level OCR Biology (42 decks)

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