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Question 1

Cells require

Answer 1

Energy

Question 2

What is ATP

Answer 2

the major energy intermediate (currency) of the cell

Question 3

What bonds do ATP consist of and what is their key feature

Answer 3

Phosphoanhydride bonds
- they are very high energy

Question 4

Answer 4

Question 5

If a cell is going to spend ATP, the cell needs an…

Answer 5

…ATP income (ATP synthesis)!

Question 6

Answer 6

Question 7

The ΔG (change of free energy) of a reaction tells us about:

Answer 7

• The relative abundance of the substrates and products
• The energy stored in the chemical bonds of the products and
  substrates

Question 8

ΔG < 0

Answer 8

ΔG < 0 for A —> B : reaction is spontaneous/ energy released/
energetically favourable

(Energy is higher then B)

Question 9

ΔG = 0

Answer 9

ΔG = 0 for A —-> B : reaction is at equilibrium/ no change in energy

Question 10

ΔG > 0

Answer 10

ΔG > 0 for A —-> B : is not spontaneous/ energy required/ energetically unfavourable

Question 11

ATP hydrolysis is genergetically_______
ATP synthesis is genetically_______

Answer 11

ATP hydrolysis is energetically favourable (ΔG’ = -30 kJ/mol)
ATP synthesis is energetically unfavourable (ΔG’ = 30 kJ/mol)

Question 12

Delta G is specific to…

Answer 12

• a specific reaction under specific conditions

Question 13

Delta G’ under standard conditions

Answer 13

All reactants 1M
PH 7

Question 14

Reaction coupling

Answer 14

If ΔG1 + ΔG 2 < 0 then coupled reaction is energetically favourable

Enzymes often couple reactions to drive necessary unfavourable reactions

Question 15

Reaction coupling example - the hexokinase reaction (glycolysis first step) what does it do (in terms of coupling) to make glucose 6-phosphate.

Answer 15

Question 16

Pathways for processing food molecules for ATP synthesis - two key reaction types?

Answer 16

1 . Those involving ADP and ATP
2. Redox reactions Fuel molecules get oxidized - something needs to be reduced (provide the oxidizing power)

Coenzymes: NAD and FAD are reduced

Question 17

Redox reactions involve

Answer 17

Redox reactions involve the transfer of electrons (e -)

Question 18

What to biological redox reactions involve? What kind of enzymes catalyse these reactions

Answer 18

Biological redox reactions often involve the transfer of hydrogen atoms (includes an e -)

Hydrogen referred to as a reducing equivalent

The enzymes that catalyse these reactions are often called dehydrogenases ( e.g. lactate dehydrogenase)

Question 19

How much energy is realises from carbohydrate and lipid respectively.

Answer 19

Question 20

Stepwise oxidation of fuel molecules occurs in the pathways - how does this compare to the direct burning of sugar?

Answer 20

• a number of little oxidation’s reassessing a little bit of energy each time to be captured in ATP

Question 21

Features of co-enzymes and features of co-enzymes for the pathways

Answer 21

• Class of co-factors
• Small organic molecules
• Co-substrates
• Often derived from vitamins

Key features for the pathways:
• Low concentration in cells
• Act as carriers
• Exist in two forms

Question 22

Nicotinamide adenine dinucleotide - what is it derived from? What is its structure and what does it do?

Answer 22

Derived from Niacin (vitamin B3)

Accepts a hydrogen and an electron in metabolic pathways (glycolysis, fatty acid oxidation, citric acid cycle)

Question 23

NAD undergoes a ____-electron reduction

Answer 23

NAD undergoes a two-electron reduction ( accepts two reducing equivalents)

Question 24

Two forms of NAD - and example of the reaction

Answer 24

NAD+ NADH
(oxidized form) (reduced form)

Question 25

Flavin adenine dinucleotide
- what is it derived from?
- what does it do?

Answer 25

Accepts two hydrogens in pathways (fatty acid oxidation, citric acid cycle)

Flavin coenzymes are tightly bound to the proteins with which they interact (flavoproteins)

Question 26

FAD undergoes a ___-electron reduction

Answer 26

FAD undergoes a two-electron reduction
(accepts two reducing equivalents) (gains to hydrogens

Question 27

Coenzyme A: what os it derived from? What does it carry? What are its two forms?

Answer 27

Derived from pantothenic acid (vitamin B5)

Not a carrier of electrons (not reduced/oxidized)

Carries: acyl groups
CH 3 (CH2 )n CH2COO-

Two forms: free coenzyme A: CoASH
acyl group attached: Acyl-CoA (AcCoA)

Question 28

Structure of free CoASH and structure of acyl group attached to Acyl-CoA

Answer 28

In free form nothing is bound to the SH

In Acyl-CoA from the acyl groups gets added to the S group