Cell Metabolism 1 Flashcards

1
Q

What are the 6 types of reactions?

A
  1. Oxidation-reduction (e transfer)
  2. Ligation requiring ATP cleavage (form covalent bonds)
  3. Isomerisation
  4. Group transfer
  5. Hydrolytic
  6. Addition/removal of functional groups (make/break double bonds)
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2
Q

Where does glycolysis occur?

A

Cytoplasm

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3
Q

Is glycolysis aerobic?

A

No

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4
Q

What are the 2 stages of glycolysis?

A
  1. Formation of high energy compound
  2. Splitting
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5
Q

How is ATP involved in each of the 2 stages?

A
  1. Invest ATP
  2. Generate ATP
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6
Q

What reaction does glucose undergo? (reactant, product, enzyme, type)

A

Glucose —> Glucose-6-phosphate
- Hexokinase (use ATP)
- Group transfer

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7
Q

What are 2 important features of step 1?

A
  1. Irreversible so commits glucose to glycolysis
  2. Negative product so trapped in cell
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8
Q

What can G6P also be used in?

A

Pentose phosphate pathway

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9
Q

What reaction does G6P undergo?

A

Glucose-6-phosphate —> Fructose-6-phosphate
- Phosphoglucose isomerase
- Isomerisation

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10
Q

Why is F6P produced?

A

Can split to equal halves

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11
Q

What reaction does F6P undergo?

A

Fructose-6-phosphate —> Fructose-1,6-bisphosphate
- Phosphofructokinase (use ATP)
- Group transfer

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12
Q

What are the high energy compounds of glycolysis?

A
  1. Dihydroxyacetone phosphate
  2. Glyceraldehyde-3-phosphate
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13
Q

What reaction does F16BP undergo?

A

Fructose-1,6-bisphosphate —> Dihydroxyacetone phosphate + Glyceraldehyde-3-phosphate
- Aldolase
- Hydrolytic

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14
Q

Which enzyme controls the entry of sugars into glycolysis?

A

Phosphofructokinase

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15
Q

What is important about TP1 deficiency?

A

Only fatal glycolytic enzymopathy

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16
Q

What reaction does DHAP undergo?

A

Dihydroxyacetone phosphate —> Glyceraldehyde-3-phosphate
- Triose phosphate isomerase
- Isomerisation

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17
Q

What reaction does G3P undergo?

A

Glyceraldehyde-3-phosphate —> 1,3-Bisphosphoglycerate
- Glyceraldehyde-3-phosphate dehydrogenase (generate NADH)
-Redox and Group transfer

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18
Q

What reaction does 13BPG undergo?

A

1,3-Bisphosphoglycerate —> 3-Phosphoglycerate
- Phosphoglycerate kinase (generate ATP)
- Group transfer

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19
Q

What reaction does 3PG undergo?

A

3-Phosphoglycerate —> 2-Phosphoglycerate
- Phosphoglycerate mutase
- Isomerisation

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20
Q

What reaction does 2PG undergo?

A

2-Phosphoglycerate —> Phosphoenolpyruvate
- Enolase
- Group removal

21
Q

What reaction does PEP undergo?

A

Phosphoenolpyruvate —> Pyruvate
- Pyruvate kinase (generate ATP)
- Group transfer

22
Q

Which glycolysis reaction is dehydration?

A

2PG —> PEP + H2O

23
Q

Which 2 reactions use ATP investment?

A
  1. G —> G6P
  2. F6P —> F16BP
24
Q

Which 2 reactions generate ATP?

A
  1. 13BPG –> 3PG
  2. PEP —> P
25
Q

Which reaction generates NADH?

A

G3P —> 13BPG

26
Q

What are the 10 steps of glycolysis?

A
  1. G —> G6P
    - H K
  2. G6P —> F6P
    - PG I
  3. F6P —> F16BP
    - PF K
  4. F16BP —> DHAP + G3P
    - A
  5. DHAP —> G3P
    - TP I
  6. G3P —> 13BPG
    - G3P D
  7. 13BPG —> 3PG
    - PG K
  8. 3PG —> 2PG
    - PG M
  9. 2PG —> PEP
    - E
  10. PEP —> P
    - P K
27
Q

What is the overall equation of glycolysis?

A

Glucose + 2 NAD —> 2 Pyruvate + 2 NADH + 2 ATP

28
Q

When does the PPP occur?

A

Anabolic reactions

29
Q

Which 2 molecules are important in the PPP?

A
  1. Ribose-5-phosphate
  2. NADPH
30
Q

When are each of the 4 modes of PPP used?

A
  1. R5P > NADPH needed
  2. R5P + NADPH needed
  3. R5P < NADPH needed
  4. NADPH + ATP needed
31
Q

Which PPP mode is used in RBCs and why?

A

3
- NADPH maintains reduced glutathione (antioxidant)

32
Q

What is the reaction of mode 3 of the PPP?

A

G6P + 12 NADP + 7 O2 —> 6 CO2 + 12NADPH + 12 H+ + Pi

33
Q

What are the 2 reactions of alcoholic fermentation?

A
  1. Pyruvate —> Acetaldehyde
    - Pyruvate decarboxylase (make CO2)
  2. Acetaldehyde —> Ethanol
    - Alcohol dehydrogenase (use NADH)
34
Q

What are the 3 fates of pyruvate?

A
  1. Alcoholic fermentation
  2. Lactate production
  3. Acetyl CoA production
35
Q

Where does alcoholic fermentation usually occur?

A

Yeast

36
Q

What is the reaction of generation of lactate?

A

Pyruvate —> Lactate
- Lactate dehydrogenase (use NADH)
- Reversible

37
Q

When does generation of lactate occur?

A

Limited oxygen

38
Q

What must be a product of the 3 fates of pyruvate?

A

NAD+

39
Q

What is the reaction of CP?

A

Creatine Phosphate + ADP —> Creatine + ATP
- Creatine kinase (make ATP)
- Reversible

40
Q

Why must CP be used as a buffer?

A

ATP does not sustain muscle contraction for long enough during exercise

41
Q

What is the ΔG of ATP hydrolysis?

A

-31 kJ/mol

42
Q

What is the ΔG of CP hydrolysis?

A

-43.1 kJ/mol

43
Q

What is the muscle contraction time for ATP vs CP hydrolysis?

A

1 vs 4 secs

44
Q

What is the reaction of acetyl CoA generation?

A

Pyruvate + HS-CoA + NAD —> Acetyl CoA + CO2 + NADH
- Pyruvate dehydrogenase complex (make NADH)

45
Q

Where does acetyl CoA generation occur?

A

Mitochondria

46
Q

Which bond in acetyl CoA is most important and why?

A

Thioester bond
- high energy so readily hydrolysed
- allows ACoA to donate acetate

47
Q

What deficiency causes Beri-Beri and why?

A

Thiamine (vit B1)
- cofactor in PDH complex
- can readily lose proton so becomes a carbanion that can attack pyruvate

48
Q

What are the 3 symptoms of Beri-Beri?

A
  1. PNS damage
  2. Weak musculature
  3. Dec cardiac output