Biochemistry of Metabolism Flashcards Preview

BIO1332 - Biochemistry > Biochemistry of Metabolism > Flashcards

Flashcards in Biochemistry of Metabolism Deck (58)
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1
Q

Define metabolism:

A

All chemical reactions involved in maintaining the living state of the cells and the organism

2
Q

Criteria for a metabolism:

A
  • Individual enzyme reactions rarely occur in isolation
  • Organised into pathways
  • Pathways interconnect onto networks
3
Q

What is the currency of free in energy on biological systems?

A

ATP

4
Q

What is ATP?

A

Primary cellular energy carrier through the triphosphate group

5
Q

What does ATP donate free energy to?

A

Anabolism/biosynthesis

  • Mechanical work/movement
  • Active molecular transport
6
Q

How do you get energy form ATP?

A

hydrolyis

7
Q

ATP + H20 =

A

ADP + Pi + H+
or
AMP + PPi + H+

8
Q

What dos hydrolyse of ATP result in?

A

High phosphoryl transfer potential

9
Q

What does the standard free energy of hydrolysis vary among?

A

Phosphorylated compounds

10
Q

What are the major electron acceptors in biological systems?

A

NAD+ and NADP+

11
Q

What do oxidation of fuel molecules result in?

A

Transfer of electrons to the terminal electron acceptor via carries

12
Q

What is the terminal electron acceptor?

A

O2

13
Q

NADH to NAD+ + H+ +2E^-

Is it reduction or oxidation?

A

Oxidation

14
Q

NAD+ + H+ +2E^- to NADH

Is it reduction or oxidation?

A

Reduction

15
Q

NADP+ + H+ +2E^- to NADPH

Is it reduction or oxidation?

A

Reduction

16
Q

NADPH to NADP+ + H+ +2E^-

Is it reduction or oxidation?

A

Oxidation

17
Q

What is the catabolic pathway?

A

Degradation/oxidation of fuel molecules to generate free energy

18
Q

What are the three stages of catabolic pathway?

A
  • Digestion and hydrolysis
  • Conversion
  • Oxidation
19
Q

What happens in stage 1 of catabolic pathway?

A

Breaking down of complex molecules

20
Q

What happens in stage 2 of catabolic pathways?

A

Breaking down to 2-, 3-carbon compounds and acetyl CoA

21
Q

What happens in stage 3 of catabolic pathways?

A

Oxidation of acetyl CoA via citric acid cycle and electron flow to O2 via NADH

22
Q

What are the major groups of energy rich nutrients?

A
  • Carbohydrates
  • Lipids
  • Protein
23
Q

What are minor dietary components?

A

Vitamins, minerals, drugs and toxins

24
Q

What are the the different fates of nutrients?

A
  1. Oxidation to generate energy
  2. Storage, then release
  3. Conversion
25
Q

Overview of glucose metabolism:

A
  1. Storage as glycogen
  2. Conversion to nucleotides and fatty acids
  3. Generation of ATP energy
26
Q

Why is the catabolism of glucose so important?

A

Glucose accounts for more than 80% of dietary carbohydrate catabolism.

27
Q

Galactose + glucose =

A

Lactose

28
Q

Fructose + glucose =

A

Sucrose

29
Q

Overview of aerobic glucose metabolism + OXYGEN:

A
  1. Storage as glycogen
  2. Conversion to nucleotides and fatty acids
  3. Generation of ATP energy
30
Q

Overview of anaerobic glucose metabolism – NO OXYGEN:

A
  1. Storage as glycogen
  2. Conversion to nucleotides and fatty acids
  3. Generation of lessATP energy
  4. Lactate
31
Q

What is the difference between anaerobic and aerobic glucose metabolism?

A

There is no citric acid cycle in anaerobic only production of lactate

32
Q

What does the production of lactate cause?

A

Musle fatigue and cramp

33
Q

Overview of anaerobic glucose metabolism in yeast cells:

A

Production of CO2 and ethanol

34
Q

Overview of glycolysis:

A
  • Rapid energy source for short, intense bursts of exercise

- Both prokaryote and eukaryote

35
Q

What is the Net outcome of glycolysis?
1 glucose —
2 ADP —-
3 NAD+ ——

A

2 Pyruvate
2 ATP
2 NADH

36
Q

What are three stages of glycolysis?

A
  1. the investment stage
  2. the investment stage continuous
  3. the energy generation stage
37
Q

What happens at stage 1 of glycolysis?

A
  1. Glucose receives a phosphate group from ATP - irreversible
  2. Glucose 6-phosphate is isomerised
  3. Fructose -6 phosphate is phosphorylated
    A rate limiting step
38
Q

What happens at stage 2 of glycolysis?

A
  1. Fructose 1,6-bisphosphate is cleaved into two 3-carbon molecules that are isomers

Glyceraldehyde 3-phosphate is on the direct pathway of glycolysis

Dihydroxyacetone phosphate is isomerised to glyceraldehyde 3-phosphate generating two molecules for subsequent steps.

39
Q

What happens at stage 3 of glycolysis?

A
  1. Generation of phosphorylated
    1,3-Bisphosphoglycerate via oxidation of the aldehyde group
    Reduction of NADH
  2. Phosphoryl group transfer from 1,3-Bisphosphoglycerate Generation of ATP
  3. Phosphoryl group is shifted from the 3 carbon to the 2 carbon position
  4. Dehydration of 2-Phosphoglycerate elevates the transfer potential9. Phosphoryl group transfer from Phosphoenolpyruvate
    Generation of ATP
40
Q

What does glucose + ATP produce in the first stage of glycolysis?

A

Glucose-6-phosphate + ADP

Catalysed by hexokinase

Irreversible reaction

41
Q

What does Fructose-6-phosphate + ATP produce in the first stage of glycolysis?

A

Fructose 1,6-BP + ADP

Catalysed by phosphofructokinase

Irreversible reaction

Rate-limiting control point

42
Q

What does G-3-P + NAD+ + Pi produce in the third stage of glycolysis?

A

1,3 bisphosphoglycerate
+ NADH + H+

Catalysed by G-3-P dehydrogenase.

Reversible reaction

Oxidation reaction

43
Q

The overall picture of glycolysis:

Glucose + 2Pi + 2 ADP + 2 NAD+ produced…

A

2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H20

44
Q

What is the overall free energy released in glycolysis?

A

197 KJ/mol

45
Q

How are ADP and NAD+ regenerated?

A

NAD+ is regenerated via either:-

  1. Lactate dehydrogenase. (Anaerobic)
  2. Oxidative phosphorylation. (Aerobic)
46
Q

How is metabolism controlled?

A

By controlling selected key enzymes

47
Q

Which enzymes are controlled in metabolism?

A
  • Irreversible enzymes
  • Enzymes at the start of a pathway or a branchpoint
  • Rate limiting enzymes e.g. phosphofructokinase
48
Q

How are the enzymes controlled in the metabolism?

A
  • By altering levels of synthesis of key enzymes (slow)

- By altering the activity of key enzymes (fast) e.g. phosphofructokinase.

49
Q

Does insulin increase or decrease the rate of metabolism when introduced?

A

Increase

50
Q

Does glucagon increase or decrease the rate of metabolism when introduced?

A

Decrease

51
Q

What is energy balance?

A

The energy put in (DIET) vs the energy put out (EXERCISE)

52
Q

What is need for a healthy energy balance?

A

Diet + products of anabolic pathways

must be balanced by catabolic pathways

53
Q

What is type 1 diabetes?

A

Deficiency of insulin

54
Q

What are symptoms of a diabetes 1?

A
  • high blood pressure (Hyperglycaemia)
  • Fatigue
  • Weight loss
  • Excessive hunger
55
Q

How can obesity lead to diabetes?

A

Excess metabolic products are stored as fat

Can lead to insulin resistance

56
Q

What is diabetes 2?

A

Insulin resistance

57
Q

What are the symptoms of diabetes 2?

A
  • high blood pressure (Hyperglycaemia)
  • compensated by increase insulin production
  • Impaired pancreas function to generate sufficient insulin
58
Q

Use this quiz:

A

http://www.purposegames.com/game/glycolysis-quiz#