Lecture 1 - Glycolysis Flashcards

1
Q

What type of reaction does a synthase enzyme catalyze?

A

Condensation reactions without requirement of a nucleoside triphosphate

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2
Q

What are the 2 important equations to find delta G?

A
  • delta G = -RTlnKeq

- delta G = -nF delta E

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3
Q

When does gluconeogenesis occur?

A

During energy rich phases, to build more glucose for storage

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4
Q

What is the major difference between fermentation and production of acetyl-CoA?

A
  • Fermentation produces a net of 2 ATP

- Acetyl-CoA production produces a net of 32 ATP

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5
Q

What is glucose stored as?

A

Glycogen or starch

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6
Q

What type of reaction does a synthetase enzyme catalyze?

A

Condensation reactions that use nucleoside triphosphates

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7
Q

What type of reaction does a ligase enzyme catalyze?

A

Condensation reactions in which 2 atoms are joined together, using ATP as the energy source

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8
Q

What type of reaction does a lyase enzyme catalyze?

A

Cleavage with electronic rearrangements

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9
Q

What type of reaction does a kinase enzyme catalyze?

A

Transfer phosphoryl groups

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10
Q

What type of reaction does a phosphatase enzyme catalyze?

A

Removal of a phosphoryl group from a phosphate ester

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11
Q

What type of reaction does a phosphorylase enzyme catalyze?

A

Displacement reactions in which phosphate is the attacking species

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12
Q

Does hexokinase work in one or both directions?

A

One

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13
Q

What enzyme catalyzes the reaction of glucose-6-phosphate to glucose (reverse of step 1)?

A

Glucose-6-phosphatase

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14
Q

Does phosphohexose isomerase work in one or both directions?

A

Both

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15
Q

What is the cofactor in step 2?

A

Mg2+

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16
Q

Does phosphofructokinase work in one or both directions?

A

One

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17
Q

What enzyme catalyzes the reaction of fructose-1,6-bisphosphate to fructose-6-phosphate (reverse of step 3)?

A

Fructose-1,6-bisphosphatase

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18
Q

What are the cofactors for step 3?

A
  • ATP -> ADP

- Mg2+

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19
Q

What are the cofactors for the reverse of step 3?

A
  • H2O in

- Pi out

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20
Q

What is phosphofructokinase inhibited by?

A

High energy signals ATP and citrate

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21
Q

What is phosphofructokinase activated by?

A

Low energy signals ADP and AMP

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22
Q

What is fructose-1,6-bisphosphatase activated by?

A

High energy signals ATP and citrate

23
Q

What is fructose-1,6-bisphosphatase inhibited by?

A

Low energy signals ADP and AMP

24
Q

What is the general function of phosphofructokinase?

A

Generate energy when energy levels are low

25
Q

What is the general function of fructose-1,6-bisphosphatase?

A

Store energy when energy levels are high

26
Q

What happens to an enzyme in the presence of an activator?

A

Binds and converts the enzyme to the more active R-state

27
Q

What happens to an enzyme in the presence of an inhibitor?

A

Binds and converts the enzyme to the less active T-state

28
Q

What does phosphofructokinase have binding sites for?

A

Fructose-6-phosphate, ATP, and ADP

29
Q

Does aldolase work in one or both directions?

A

Both

30
Q

Which direction is favoured in step 4 and how is this counteracted?

A
  • Formation of fructose-1,6-bisphosphate (reverse) is favoured
  • Counteracted by the products being removed quickly in following steps
31
Q

Does triose phosphate isomerase work in one or both directions?

A

Both

32
Q

Does G-3-P dehydrogenase work in one or both directions?

A

Both

33
Q

What are the cofactors of step 6?

A
  • Pi in

- NAD+ -> NADH and H+

34
Q

What are the cofactors of step 7?

A
  • ADP -> ATP

- Mg2+

35
Q

What is substrate level phosphorylation?

A

The addition of a phosphate group from the substrate to ADP

36
Q

Does phosphoglycerate work in one or both directions?

A

Both

37
Q

What is the purpose of Mg2+ as a cofactor?

A

To silence the 2- charge of phosphate be transferred

38
Q

Does phosphoglyercate mutase work in one or both directions?

A

Both

39
Q

What is the cofactor for step 8?

A

Mg2+

40
Q

Does enolase work in one or both directions?

A

Both

41
Q

What is the cofactor of step 9 and what does this do?

A
  • H2O out
  • Shifts the energy state of the molecule, so that much more energy is released with the removal of the phosphate from PEP
42
Q

Why does phosphoenolpyruvate (PEP) have a greater negative G than 2-phosphoglycerate (2-PGA)?

A

Because PEP really wants to get rid of its phosphate group

43
Q

Does pyruvate kinase work in one or both directions?

A

One

44
Q

What are the cofactors in step 10?

A
  • ADP -> ATP

- Mg2+ and K+

45
Q

How can pyruvate be converted back to PEP?

A
  • Pyruvate is converted to oxaloacetate by pyruvate carboxylase
  • Oxaloacetate is converted to PEP by PEP carboxykinase
46
Q

What are the cofactors needed in the conversion of pyruvate to oxaloacetate?

A
  • CO2 in

- ATP -> ADP

47
Q

What are the cofactors needed in the conversion of oxaloacetate to PEP?

A
  • GTP -> GDP

- CO2 out

48
Q

Where is pyruvate carboxylase found?

A

Mammalian liver and kidneys

49
Q

Where is PEP carboxykinase found?

A

Heart and skeletal muscle

50
Q

Why is pyruvate kinase inhibited?

A

So that PEP can be used to make glucose

51
Q

What happens to the NADH produced by glycolysis?

A

It is re-oxidized in the mitochondria via the ETC

52
Q

How can glycolysis take place with lactose as the starter molecule?

A
  • Lactose is converted to galactose
  • Galactose is converted to Glc-1-P
  • Glc-1-P is converted to Glc-6-P and the rest of glycolysis occurs normally
53
Q

How can glycolysis take place with glycogen or starch as a starter molecule?

A
  • Glycogen or starch are converted to Glc-1-P

- Glc-1-P is converted to Glc-6-P and the rest of glycolysis occurs normally