Introduction to Metabolism Flashcards

1
Q

What is metabolism?

A

Metabolism - by which an organism extracts energy from their environment and use this to synthesise large molecules

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2
Q

Why is metabolism important in our daily lives?

A

Good health depends on a well-balanced metabolism Many disorders involve changes in the balance of metabolic activated (e.g. - Diabetes, obesity or vitamin deficiencies)

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3
Q

How much oxygen does the resting human have and how much does this go up by when exercising?

A

Resting human - approx 250m O2/min (1.25 litres / 5 mins) Can increase 5 times during exercise

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4
Q

What is oxygen used for in the body?

A

Oxygen is used to oxidise substrates and produce energy for the body’s needs

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5
Q

What is the definition of oxidation?

A

Oxidation is the addition of oxygen to molecules - Also the removal of electrons

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6
Q

What is the definition of reduction?

A

Reduction is the removal of oxygen from molecules - Also addition of electrons

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7
Q

What acronym is used two remember what one loses and gains electrons?

A

OIL RIG; Oxidation Is Loss of electrons Reduction Is Gain of electrons

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8
Q

What is the definition of catabolism?

A

Catabolism - Breakdown of large molecules to smaller ones, releasing energy

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9
Q

What is the definition of anabolism?

A

Anabolism - Process by which large molecules are built from smaller ones, requires an energy input

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10
Q

How can anabolism and catabolism work together?

A

The energy produced by catabolism is used to drive anabolism and other energy-requiring processes

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11
Q

What does delta G stand for?

A

Change in free energy

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12
Q

What always happens in chemical reactions?

A

An absorption or release of energy

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13
Q

For the reaction of A + B C + D, what is the formula to work out the change in free energy (delta G)?

A

(Delta) G = (Delta)G^o + RT loge [C][D]/[A][B] (Delta) G = Free energy change for the reaction with reactants at the concentrations given (Delta) G^o = Standard free energy change (when all reactants are present at a concentration of 1.0 M) R = Gas constant T = Absolute temperature

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14
Q

What is the only way that a reaction can occur spontaneously without an energy input ?

A

If the free energy change (Delta G) is negative between the starting materials and final products

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15
Q

What does the magnitude of delta G not indicate ?

A

How rapidly the reaction will take place

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16
Q

What does the reaction rate depend on ?

A

The energy hump that must be climbed for the reaction to occur, known as the free energy activation (delta G*)

17
Q

What does a negative delta G mean?

A

Exothermic reaction

18
Q

What state does a reaction normally involve ?

A

An intermediate (transitional) state E.g. A + B < A-B > C + D

19
Q

What does a catalyst do?

A

Speeds up rate of a reaction and lowers free energy of activation

20
Q

How can individual reactions with a positive free energy be driven passively?

A

By a reaction with a negative free energy change (delta G^o)

21
Q

What happens if energy is release too quickly?

A

It oxidises the substrate and it releases heat energy - Like burning food

22
Q

How is the energy release during cataclysm capture and stored?

A

As ATP (or sometimes AMP or ADP of lower energies)

23
Q

What bond in ATP are high energy?

A

The di-ester bonds

24
Q

What is Pi?

A

Inorganic phosphate

25
Q

What is phosphorylation?

A

Adding a phosphate group to a molecule (e.g converting ADP to ATP)

26
Q

What is able to phosphorylate molecules?

A

Kinases

27
Q

What is hydrolysis of ATP used for?

A

Hydrolysis of ATP is used to drive energy-requiring processes (e.g - anabolism, movement and ion transport) ATP being hydrolysed to ADP + Pi gives off the largest amount of energy ( -7 to -12 kcal/mol)

28
Q

How is ATP formed?

A

When fuel molecules are oxidised

29
Q

What other nucleotide is used to form energy stores?

A

Guanosine to from Guanosine diphosphate (GDP) and Guanosine triphosphate (GTP) which serves a similar role to ADP and ATP

30
Q

How much ATP does the resting human consume in 24 hours?

A

40KG/6.5stone of ATP

31
Q

How much ATP do human consume per minute of strenuous exercise?

A

0.5kg/min

32
Q

What 4 things is ATP required for?

A
  • Body movement (via muscular contraction) - Cellular movements (via cytoskeleton) - Active transport - Synthesis of large molecules
33
Q

What processes can generate ATP?

A

below

34
Q

What are the 3 ways acetyl CoA is made?

A

Fats -> Fatty acids and glycerol = Acetyl CoA Polysaccharides -> Glucose and other sugars = Acetyl CoA Proteins -> Amino acids = Acetyl CoA

35
Q

What happens to Acetyl CoA to make ATP?

A

Acetyl CoA splits from CoA and acetyl goes into citric acid cycle, where 2CO2 is made and 1 electron is made which is used to convert ADP into ATP and release O2 and water as biproducts

36
Q

What 2 things must work together to produce energy appropriate for different body requirements? When are difficulties of this found?

A

Energy producing and energy requiring processes This balance is important in adjustment during dietary changes (e.g starvation or dieting), while an imbalance can be seen in diseases like diabetes

37
Q

What 3 ways can the regulation of metabolism be achieved by?

A

This can be achieved by: 1. Changes in amounts of substrates and products of pathways (e.g. ratio of ATP to ADP + Pi affects energy producing and energy-requiring pathways in opposite ways) 2. Changes in amounts of key enzymes 3. Changes in activity of key enzymes: •Allosteric changes (i.e end products can allosterically bind to affect pathway rate, increase or decrease it •Effects of substrate and downstream products on enzyme activity •Covalent modification of enzymes (e.g. phosphorylation)

38
Q

What else has a major regulatory affect on some enzymes?

A

Hormones such as insulin, glucagon and adrenaline can have a major regulatory effect on some enzymes