Introduction to Metabolism Flashcards

(35 cards)

1
Q

Define the term : Metabolism

A

Mechanisms which couple the demand for energy, with the fuel supply

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2
Q

Define the term : Anabolism

A

SYNTHESIS of new molecules to store energy

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3
Q

Define the term : Catabolism

A

DEGRADATION of molecules to release energy

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4
Q

Define the term : Oxidation

A

Gain of oxygen

OR

Loss of hydrogen

OR

Loss of electrons from molecules

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5
Q

Define the term : Reduction

A

Loss of oxygen

OR

Gain of hydrogen

OR

Addition of electrons

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6
Q

Function of ATP

A

Adenosine Triphosphate

The essential link between anabolism and catabolism
Energy currency

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7
Q

How many stage of metabolism are there ?

A

3 stages

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8
Q

Describe what happens in stage 1 of metabolism

A

Digestion in the GI tract
Absorption and Transport in the blood

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9
Q

Describe what happens in stage 2 of metabolism

A

In the cell cytoplasm :

  • Anabolic
  • Catabolic

reactions occur

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10
Q

Where does stage 2 of metabolism occur ?

A

In the cell cytoplasm

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11
Q

Anabolic

A

Nutrients built into storage molecules

e.g. glycogen/protein/adipose

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12
Q

Catabolic

A

Nutrients/ Storage molecules are broken down

e.g. pyruvate / acetyl CoA

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13
Q

Where does stage 3 of metabolism occur ?

A

In the mitochondria

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14
Q

Describe what happens in stage 3 of metabolism

A

IN mitochondria :

Catabolism requiring oxygen to completely break down food and generate ATP.

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15
Q

State the 2 nutritional states

A

Absorptive (fed)
Post-absorptive (fasting)

Energy is stored in the absorptive state and released in the post-absorptive

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16
Q

How do we capture energy release from food ?

A

The process of cellular respiration (stages 2+3) enables stepwise oxidation of food (e.g. glucose)

Captured as chemical energy, to store in high energy phosphate bonds of ATP.

17
Q

What is Redox ?

A

Reduction and Oxidation of molecules

Cellular respiration utilises these reactions to power the synthesis of ATP

18
Q

State the 2 key coenzymes involves in metabolism

A

NAD - Nictotinamide adenine dinucleotide
FAD - Flavin adenine dinucleotide

19
Q

How is NAD produced ?

A

Vitamin B3 - Niacin

20
Q

How is FAD produced ?

A

Vitamin B2 - Riboflavin

21
Q

State the stages of cellular respiration

A

Glycolysis
Citric acid cycle / Krebs cycle
Oxidative phosphorylation

22
Q

Where is energy stored in ATP ?

A

Energy is stored in phosphate bonds

Energy produced by catabolism is used to drive anabolism and other energy requiring processes.

23
Q

How much energy is released when ATP is hydrolysed to ADP + Pi ?

A

-30.5 kJ/mol of energy is released

24
Q

Describe the stages in cellular respiration

A

Stage 1 :

Digestion in the GI tract - absorption and transport to cells

Stage 2 : Glycolysis in the cell cytoplasm

Stage 3 : Citric Acid cycle and ox. phos. in mitochondria

… Ultimately yielding ATP

25
Describe the 1st Law of Thermodynamics
The total energy of a system is constant Energy can neither be created nor destroyed Energy can be converted from one form to another
26
State some types of energy
Kinetic energy Potential energy
27
What is Gibbs free energy ?
The energy needed to transform substrates into the transition state. All reactions need to overcome the energy barrier
28
Describe Gibbs free energy for a graph where free energy of substrate is equal to product
Delta G = 0
29
Describe Gibbs free energy for a graph where free energy of substrate is higher than the product
Delta G = negative So reaction is favourable
30
Describe Gibbs free energy for a graph where free energy of substrate is lower than the product
Delta G = positive So reaction is unfavourable
31
Exergonic
Favourable -delta G Releases more energy than input
32
Endergonic
Unfavourable +delta G Requires more energy input than it yields
33
Explain how enzyme reactions can be coupled to utilise 'free energy'
1st step of glycolysis : Phosphorylation of glucose : endergonic Coupled to hydrolysis of ATP --> ADP + Pi : exergonic
34
State an example of a catabolic reaction
Breakdown of glucose to pyruvate Mobilisation of fatty acids from lipid stores to feed into cellular respiration
35
Metabolism is not 100% effective at capturing food energy. What form of energy is most commonly lost in the process ?
Thermal energy