module 5 - 18.3 the krebs cycle Flashcards

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1
Q

what happens during the krebs cycle? (stage 1-5)

A
  1. link reaction delivers acetyl groups into Krebs Cycle, they are attached to coenzyme A
  2. the acetyl group combines with the oxaloacetate to form the 6-carbon citrate
  3. coenzyme A is returned to link reaction
  4. citrate molecule is decarboxylated and dehydrogenated to produce 5-carbon intermediate, co2 and reduced NAD
  5. the 5C intermediate is decarboxylated and dehydrogenated to produce 4-carbon intermediate, co2 and reduced NAD
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2
Q

what happens during the Krebs cycle? (stage 6-9)

A
  1. the 4 carbon intermediate undergoes substrate level phosphorylation to make ATP from ADP+Pi
  2. the 4-carbon intermediate is dehydrogenated to produce reduced FAD
  3. the 4-carbon intermediate is dehydrogenated to produce reduced NAD
  4. last 3 reactions convert the 4-carbon intermediate into oxaloacetate, allows Krebs cyle to turn once more
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3
Q

what is a cofactor?

A

inorganic ions such as:
- chloride ion and amylase
- magnesium ion and DNA polymerase

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4
Q

what is a coenzyme?

A

organic molecules like vitamins, loosely bound to the enzymes

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5
Q

what are prosthetic groups?

A

inorganic ions/organic molecules that are tightly bound to enzymes

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6
Q

what are the products of ONE TURN of the Krebs cycle?

A
  • 3 reduced NADs
  • 1 reduced FAD
  • 1 ATP
  • 2 CO2 molecules
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7
Q

what are the coenzymes in respiration?

A
  • NAD
  • FAD
  • CoA (coenzyme A)
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8
Q

what are NAD, FAD ABD CoA made from?

A

NAD - vitamin B3
FAD - vitamin B2
CoA - B5

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9
Q

what are the coenzymes used for in respiration?

A

used to move protons, electrons and functional groups between enzymes

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10
Q

what happens to NAD during respiration?

A
  • NAD accepts 1 hydrogen atom and an electron OR 1 proton and 2 electrons
  • NAD reduced to reduced NAD
  • NAD and NAD+ are the oxidised forms
  • reduced NAD and NADH are the reduced forms
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11
Q

what is the reaction for NAD during respiration?

A

NAD+ + H+ + 2e- ⇌ NADH

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12
Q

what happens to FAD during respiration?

A
  • FAD accepts 2 hydrogen atoms or 2 protons and 2 electrons
  • FAD is reduced to reduced FAD
  • FAD is the oxidised form
  • FADH2 is the reduced form
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13
Q

how can reduced NAD/FAD be written?

A

reduced NAD: NADH
reduced FAD: FADH2

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14
Q

what is the reaction for FAD during respiration?

A

FAD + 2e- + 2H+ → FADH2

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15
Q

what is reduced NAD/NADH used for?

A
  • used in last stage of aerobic respiration to produce ATP from ADP + Pi
  • done by oxidative phosphorylation
  • 1 reduced NAD can be used to produce 3 ATP molecules
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16
Q

what is reduced FAD/FADH2 used for?

A
  • used in last stage of aerobic respiration to produce ATP from ADP +Pi
  • done by oxidative phosphorylation
  • 1 reduced FAD can be used to produce 2 ATP molecules
17
Q

what is oxidation?

A

adding oxygen/removing hydrogen

18
Q

what is reduction?

A

adding hydrogen/removing oxygen

19
Q

what is a redox reaction?

A

one molecule oxidised, one molecule reduced - happens at the same time

20
Q

where does glycolysis happen?

A

cytoplasm

21
Q

where does the link reaction happen?

A

mitochondrial matrix

22
Q

where does the Krebs cycle happen?

A

mitochondrial matrix