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Biology A2 > Respiration > Flashcards

Respiration Flashcards

1
Q

Metabolism

A

All chemical reactions that take place in a cell

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2
Q

Glycolysis

A

Splitting of 6-carbon glucose into two 3-carbon pyruvate

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3
Q

Describe the process of glycolysis

A
  • substrate level phosphorylation of glucose using 2 ATP to raise to higher energy
  • phosphorylated glucose splits into two triose phosphate
  • triose phosphate is oxidised by removing hydrogen to produce NADH
  • releases some energy to phosphorylate ADP to ATP
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4
Q

State where glycolysis occurs

A

cytoplasm

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5
Q

State the products of glycolysis per glycose

A
  • 4 ATP (net ATP 2)

- 2 NADH

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6
Q

Suggest how red blood cells (which have no mitochondria) produce ATP

A
  • anaerobic respiration

- glycolysis in cytoplasm produces ATP

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7
Q

Link Reaction

A

Production of 2-carbon acetyl coenzyme A from 3-carbon pyruvate

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8
Q

Describe the process of link reaction

A
  • decarboxylation of pyruvate by losing CO2
  • 2-carbon compound loses hydrogen by oxidation
  • reduced NAD and 2-carbon acetate formed
  • acetate combines with coA to form acetyl coA
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9
Q

Suggest how pyruvate enters the mitochondria

A

active transport

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10
Q

State where link reaction and Kreb’s cycle occur

A

mitochondrial matrix

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11
Q

Kreb’s Cycle

A
  • acetyl coA combines with 4-carbon oxaloacetate from previous cycle
  • forms 6-carbon citrate
  • decarboxylation and oxidation of citrate forms NADH and 5-carbon sugar
  • decarboxylation and oxidation of 5-carbon sugar forms 2 NADH and FADH2
  • oxaloacetate reformed
  • some energy released for substrate level phosphorylation of ADP to ATP
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12
Q

State products of Kreb’s cycle per glucose

A

Kreb’s cycle occurs twice

  • 2 ATP
  • 4 CO2
  • 6 NADH
  • 2 FADH2
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13
Q

Suggest reasons Kreb’s cycle is significant

A
  • source of intermediate compounds required to manufacture fatty acids, amino acids etc.
  • provides hydrogen atoms carried by coenzymes NAD and FAD for oxidative phosphorylation = ATP
  • regenerates 4-carbon oxaloacetate
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14
Q

Suggest how hydrogen atoms carried by coenzymes NAD and FAD are used to release energy

A
  • electrons travel along e- transport chain and H+ pumped across to intermembramal space
  • provides energy for oxidative phosphorylation
  • produces ATP
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15
Q

State where oxidative phosphorylation occurs

A

cristae

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16
Q

Describe the process of oxidative phosphorylation

A
  • NADH and FADH2 donate electrons from hydrogen atom they are carrying to first electrons carrier (NADH dehydrogenase)
  • electrons passed along electron transport chain
  • in series of oxidation-reduction reactions
  • energy released causes H+ to be pumped into intermembranal space
  • chemiosmosis of H+ down electrochemical gradient through ATP synthase
  • enzyme changes shape releasing energy to phosphorylate ADP to ATP
17
Q

Explain importance of oxygen in oxidative phosphorylation

A
  • final acceptor of H+ and electrons
  • prevents back up along chain stopping respiration
  • produces safe product of water
18
Q

Explain why mitochondria have many folds in their inner membrane (cristae)

A
  • large surface area
  • for attachment of carrier proteins
  • oxidative phosphorylation
19
Q

Explain what is meant by electron transfer chain

A
  • e- passed along a series of e- carrier proteins
  • each has a slightly lower energy level than previous
    (down energy gradient)
  • in oxidation-reduction reactions
20
Q

Suggest how energy is transported efficiently in the electron transport chain

A
  • energy released gradually
  • in small amounts
  • less wastage/used usefully
21
Q

Explain how lipids are used in respiration

A
  • lipids hydrolysed to fatty acids and glycerol
  • glycerol is phosphorylated to triose phosphate
  • triose phosphate => pyruvate => acetyl coA enters Kreb’s
  • fatty acids => acetyl coA for Kreb’s cycle
22
Q

Suggest why lipids release more energy compared to carbohydrates

A
  • fatty acids contain greater proportion of carbon atoms
  • able to produce many acetyl coA
  • which produces ATP from Krebs cycle plus NADH/FADH
  • NADH/ FADH donates H to electron transport chain to produce more ATP
  • so lipids require more oxidation
23
Q

Explain how proteins and used in respiration

A
  • proteins are hydrolysed to amino acids
  • amino acids are deaminated
  • remaining C used to make pyruvate and carbon intermediates for Kreb’s cycle
24
Q

Give reasons why aerobic respiration is inefficient

A
  • proton leakage through proton pumps so do not all form ATP
  • energy lost as heat
  • active transport of pyruvate/NADH requires ATP
25
Q

Describe anaerobic respiration in animals

A
  • all NAD and FAD is reduced
  • Kreb’s cycle and e- transfer chain stop
  • NADH gives up hydrogen to pyruvate forming lactate
  • oxidised NAD allows further glycolysis = more ATP
26
Q

Describe anaerobic respiration in plants

A
  • all NAD and FAD is reduced
  • Kreb’s cycle and e- transfer chain stop
  • pyruvate decarboxylated
  • NADH gives up hydrogen to 2-carbon compound forming ethanol
  • oxidised NAD allows further glycolysis = more ATP
27
Q

Suggest how anaerobic respiration provides a survival advantage for animals

A
  • allows ATP production to continue in oxygen shortage
  • muscles can continue to work for a short time
  • lactate can be oxidised back to pyruvate
  • further oxidised to release energy
28
Q

Suggest drawbacks of anaerobic respiration in animals

A
  • produces lactic acid
  • lactic acid causes cramps and muscle fatigue
  • pH decreases so affects enzyme activity
29
Q

Suggest two ways ATP is produced in respiration

A
  • substrate level phosphorylation

- oxidative phosphorylation

30
Q

Suggest how the majority of ATP is produced

A
  • oxidative phosphorylation
31
Q

Suggest what would happen if carbon dioxide remained in mitochondria

A
  • lower pH

- denature enzymes involve in respiration

32
Q

Suggest why it is essential that oxidised NAD is regenerated in anaerobic respiration

A
  • needs to oxidise more triose phosphate

- allows glycolysis/ fermentation to occur

33
Q

Gives uses of ATP in a cell

A
  • active transport
  • cell division
  • synthesis of DNA, proteins etc.
  • muscle contraction
  • nerve impulses
  • phosphorylation
34
Q

Suggest why link reaction and Kreb’s cycle cannot occur in absence of oxygen

A
  • without oxygen oxidative phosphorylation cannot occur
  • NAD cannot be produced
  • glycolysis produces lactic acid instead of pyruvate
  • pyruvate is required for link reaction hence Kreb’s
35
Q

Suggest why less ATP is produced in anaerobic respiration

A

Glucose is not completely broken down

36
Q

Suggest why glucose is the preferred respiratory substrate

A
  • glucose readily available to cells since concentration in blood remains relatively constant
  • fats and proteins required for other uses (i.e. fats for insulation and proteins for growth, repair etc.)
  • proteins produce toxic urea from deamination
37
Q

Suggest why respiration of lipids required more oxygen compared to carbohydrates

A
  • greater proportion of carbon atoms from fatty acid chain
  • many acetyl coA enter Krebs cycle to produce NADH/FADH
  • NADH/FADH donate hydrogen to electron transport chain
  • oxygen is final acceptor of hydrogen
  • lots of oxygen required to prevent backing up chain and stopping respiration
38
Q

Oxidative Phosphorylation

A
  • process in which ATP is formed
  • as a result of the transfer of electrons from NADH or FADH 2
  • to O 2 by a series of electron carriers

Biology A2 (15 decks)

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