LEC 10 Flashcards

Citric Acid Cycle & Electron Transport System

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1
Q

Where does the citric acid cycle happen?

A

in the inner membrane region

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2
Q

For each glucose (started with in Step #1), the citric acid cycle happens _____
One for each ____ ____ that was formed by the ______ of glucose

A
  1. twice
  2. acetyl group
  3. catabolism
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3
Q

Stage #3 - Citric Acid Cycle Step 1 (2)

A

Acetyl CoA delivers acetyl to citric acid cycle
- Acetyl combines with oxaloacetate to make citric acid.

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4
Q

Stage #3 - Citric Acid Cycle Step 2 (3)

A

Citric acid is metabolized
1. A carbon is removed, combines with O2 to make CO2.
2. NAD+ picks up 1 hydrogen and 2 electrons to NADH
3. Remaining molecule is α-ketoglutarate

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5
Q

Stage #3 - Citric Acid Cycle Step 3 (4)

A

α-ketoglutarate is metabolized
1. A carbon is removed, combines with O2 to make CO2.
2. NAD+ picks up 1 hydrogen and 2 electrons to make NADH
3. ADP to ATP
4. Remaining molecule is succinate

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6
Q

Stage #3 - Citric Acid Cycle Step 4 (2)

A

Succinate is metabolized
1. FAD picks up 2 hydrogen and 2 electrons to make FADH2
2. Remaining molecule is fumarate

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7
Q

Stage #3 - Citric Acid Cycle Step 5 (2)

A

Fumarate is metabolized
1. NAD+ picks up 1 hydrogen and 2 electrons to make NADH
2. Remaining molecule is oxaloacetate (which starts the next cycle)

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8
Q

oxaloacetate

A

Combines with Acetyl to make citric acid

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9
Q

citric acid (2)

A

oxaloacetate + Acetyl
metabolized in step 2 of citric acid cycle

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10
Q

α-ketoglutarate (2)

A
  • Left over in step 2 of citric acid cycle
  • metabolized in step 3
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11
Q

succinate (2)

A
  • Left over in step 3 of citric acid cycle
  • metabolized in step 4
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12
Q

fumarate (2)

A
  • Left over in step 4 of citric acid cycle
  • metabolized in step 5
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13
Q

Coenzyme FAD full form

A

Flavin adenine dinucleotide

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14
Q

Becomes FADH2 by picking up: (2)

A
  1. Two (2) high energy H+ ions
  2. Two (2) electrons
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15
Q

What is FADH+ used for?

A

carry these high energy ions to the final stage of energy production

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16
Q

Summary: Stage #3 – Citric Acid Cycle ATP

A

2 molecules produced by substrate level phosphorylation

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17
Q

Summary: Stage #3 – Citric Acid Cycle Coenzyme activity (2)

A
  1. Six NAD+ molecules pick-up 1 hydrogen and 2 electrons each to become 6 molecules of NADH (Go to Stage #4)
  2. Two FAD molecules pick-up 2 hydrogen and 2 electrons each to become 2 molecules of FADH2 (Go to Stage #4)
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18
Q

Summary: Stage #3 – Citric Acid Cycle What’s left?

A
  1. Four molecules of CO2 (waste)
  2. Two molecules of oxaloacetate (used to start the next cycle)
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19
Q

What molecule delivers acetyl to the citric acid cycle?

A

Acetyl CoA

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20
Q

Acetyl combines with ________ to form citric acid.

A

oxaloacetate

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21
Q

What happens to citric acid in the citric acid cycle? (4)

A
  1. A carbon is removed from citric acid
  2. combines with O₂ to form CO₂
  3. NAD+ picks up 1 hydrogen and 2 electrons to form NADH
  4. The remaining molecule is called α-ketoglutarate.
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22
Q

What is the next molecule formed after citric acid is metabolized?

A

α-ketoglutarate.

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23
Q

What happens to α-ketoglutarate in the citric acid cycle? (4)

A
  1. A carbon is removed, combines with O₂ to form CO₂
  2. NAD+ picks up 1 hydrogen and 2 electrons to form NADH. 3. ADP is converted to ATP
  3. The remaining molecule is called succinate.
24
Q

What is the next molecule formed after α-ketoglutarate is metabolized?

A

Succinate

25
Q

What happens to succinate in the citric acid cycle? (2)

A
  1. FAD picks up 2 hydrogens and 2 electrons to form FADH₂. 2. The remaining molecule is called fumarate.
26
Q

What is the next molecule formed after succinate is metabolized?

A

Fumarate

27
Q

What happens to fumarate in the citric acid cycle? (2)

A
  1. NAD+ picks up 1 hydrogen and 2 electrons to form NADH. 2. The remaining molecule is oxaloacetate, which starts the next cycle.
28
Q

Overall Summary: (Stages #1 - #3) (4)

A
  1. Glucose has been completely catabolised
  2. Six molecules of CO2 as waste (2 in prep step and 4 in citric acid cycle)
  3. Net gain of 4 ATP molecules (2 from glycolysis & 2 from citric acid cycle)
  4. xThe rest of the energy i “locked” in the hydrogen ions and electrons that are being moved to Stage #4 by coenzymes NAD+ and FAD
29
Q

Overall Summary: (Stages #1 - #3) How are ATP produced?

A

Through substrate level phosphorylation

30
Q

How does the Stage #4 – Electron Transport System start?

A

The NADH & FADH2 (from Stages #1 - #3) drop their H+ and e- in the inner membrane (cristae) of mitochondria

31
Q

Stage #4 – Electron Transport System role of carrier proteins in the membrane (step 2) (3)

A

NADH & FADH2 release electrons to carrier proteins

     1. A carrier protein accepts two high energy electrons and passes them from one protein to next in sequence

      2. During the transfer – protein acquires energy from the electron (the electron loses energy)
     
      3. The now energized carrier protein actively transports the H+ ions to the outer membrane region
32
Q

Stage #4 – Electron Transport System Step 3 (2)

A
  • now a high H+ ion concentration in the outer mitochondrial membrane
  • H+ ions diffuse back into the inner membrane of the mitochondria though ATP synthase
33
Q

ATP synthase

A

specialized enzyme channels

34
Q

What happens as H+ ions diffuse back inside?

A

oxidative phosphorylation

35
Q

“oxidative phosphorylation”

A

Oxidative = requires oxygen and that electrons have been removed
Phosphorylation = addition of phosphate group

36
Q

What happens during oxidative phosphorylation?

A

The energy from the H+ ion catalyzes the synthesis of ATP from ADP + Pi

37
Q

What happens after oxidative phosphorylation? (3)

A
  1. ATP molecules leave the inner compartment
  2. Spent H+ ions and electrons will combine with oxygen to form water (a waste product)
  3. Low energy NAD+ and FAD co-enzymes are recycled for use again
38
Q

Equation when spent H+ ions and electrons will combine with oxygen to form water (a waste product)

A

½ O2 + 2H+ + 2 e- = H2O

39
Q

Summary: Stage #4 - Electron Transport Steps Summary (6)

A
  1. H+ ions and electrons are released from co-enzymes in the inner membrane area
  2. High energy electrons “power” carrier proteins
  3. H+ ions are actively pumped to outer membrane area
  4. H+ ions diffuse back into inner membrane via ATP synthase
  5. H+ ions catalyze the formation of ATP from inorganic phosphate and ADP
  6. Approximately 34 ATP molecules produced
40
Q

Summary: Stage #4 – Electron Transport System ATP

A

34 molecules produced

41
Q

Summary: Stage #4 – Electron Transport System Coenzyme activity (2)

A
  1. NADH molecules drop off hydrogen and electrons (become NAD+ again and are reused)
  2. FADH2 molecules drop off hydrogen and electrons
    (become FAD again and are reused)
42
Q

Summary: Stage #4 – Electron Transport System What’s left?

A

6 molecules of water (waste)

43
Q

Summary: Stage #4 – Electron Transport System How are ATP produced?

A

oxidative phosphorylation

44
Q

Energy Production Recap Products (3)

A
  1. Ten NADH
  2. Two FADH2
  3. NET GAIN = 36 ATP
    38 ATP ((2 used to shuttle NADH (produced in Stage #1) from cytoplasm to Stage #4))
45
Q

Energy Production Recap Waste (2)

A

6 CO2 produced
6 H2O produced

46
Q

Other Energy Sources

A

Glycogen = 1%

Fats = 78%

Protein = 21%

47
Q

Fat Catabolism will produce about ________ as much ATP vs. ___________

A
  1. twice
  2. glycogen
48
Q

How do fats catabolize?

A

Triglycerides break down into glycerol and fatty acid tails (16-18 carbons each)

49
Q

Glycerol converted into either:
Glucose in the ____ = Glycolysis
Pyruvate = _________ Step

A
  1. liver
  2. Preparatory
50
Q

_____ acids converted into:
_______ groups = Citric Acid Cycle

A
  1. Fatty
  2. Acetyl
51
Q

Protein Catabolism

A

Proteins are broken into individual amino acids
Amine (NH2 group) are removed = urea and excreted as urine

Remaining carbon backbone enters Citric Acid Cycle at various points

52
Q

Catabolism of proteins increases significantly during starvation results in ________ ________

A

muscle wasting

53
Q

Anaerobic Respiration

A

The ability to make energy without oxygen (e.g. Glycolysis)

54
Q

What happens to pyruvate in anaerobic respiration? (2)

A
  • pyruvate does not enter the mitochondria
  • converted into lactic acid
55
Q

What is lactic acid is responsible for?

A

burning and cramping in muscle tissue when no O2