Bioenergetics Flashcards

1
Q

What is metabolism?

A

A co-ordinated set of chemical reactions catalysed by enzymes

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2
Q

What do energetics dictate?

A

The rates & equilibrium positions of reactions

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3
Q

What does a closed system eventually reach?

A

Equilibrium

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4
Q

What does an open system eventually reach?

A

A steady state

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5
Q

What is the 1st law of thermodynamics?

A

The law of conservation of energy.

Total amount of energy in a system stays the same but can be found in different forms.

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6
Q

What is enthalpy?

A

The heat absorbed during a reaction at constant pressure

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7
Q

What affect does adding heat (Q) or work (W) to a closed system have?

A

Increases enthalpy/total energy of system

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8
Q

What is the total change in enthalpy from initial to final state independent of?

A

The path taken

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9
Q

What is a reaction that gives out heat called?

What will the enthalpy of this reaction be?

A

Exothermic

Negative

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10
Q

What is a reaction that takes up heat called?

A

Endothermic

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11
Q

What is assumed during thermochemistry?

How is this different to biological reactions?

A

The reaction is at constant pressure and does no work

Some can convert chemical reactions to work

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12
Q

What are some examples of work being carried out in biological systems?

A

Mechanical work performed by muscles
Electrical work required to transmit nerve impulses
Chemical work to synthesise molecules (anabolism)

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13
Q

What is the 2nd law of thermodynamics?

A

When energy is converted from 1 form to another, some of the energy becomes unavailable to do work

E.g. heat energy dissipated into the environment cannot be re-used

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14
Q

What is entropy?

A

A measure of the disorder or unavailable energy in a system

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15
Q

What alone can drive reaction?

A

Entropy

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16
Q

What can a change in enthalpy be driven by?

A

A change in entropy

17
Q

What does the 2nd law of thermodynamics imply?

A

Entropy is always increasing

18
Q

What is free energy?

A

Energy available to do work at constant temp

19
Q

In a spontaneous process, what is the free energy change?

What happens?

A

-ve

Reaction release free energy

20
Q

What happens if the change in free energy is +ve

A

Reaction requires free energy

If that energy is NOT provided the reaction doesn’t occur

21
Q

What does increasing the entropy of protein result in?

A

Breaking protein –> amino acids

a lot more disorder in single amino acids than a structured protein

22
Q

What is catabolism?

What change in free energy values does this have?

What type of reaction is this?

A

Breaking down molecules into small units

-ve

Exergonic (releases energy)
Can be spontaneous

23
Q

What is anabolism?

What change in free energy value does this have?

What type of reaction is this?

A

Synthesising complex molecules from their basic constituents

+ve

Endergonic (absorbs heat)
Not spontaneous

24
Q

Which conditions are stable within biological systems?

Which factor has a major effect on change in free energy?

A

Temp
Pressure

Conc of components of a reaction

25
Q

What are the 2 systems adopted to make a reaction proceed in the direction required by an org?

A

> Alter conc so change in free energy becomes -ve

> Couple reaction w/ a +ve change in free energy value to one w/ a -ve value
–> so that overall the change in free energy is -ve