1. Energy Reactions In Cells

Question 1

What is metabolism?

Answer 1

Set of processes which derive energy and raw materials from food stuffs and use them to support repair, growth and activity of the tissues of the body to sustain life.

Question 2

What is catabolic metabolism?

Answer 2

Break down of larger molecules into smaller ones. Releases large amounts of energy. Oxidative (releases H atoms).

Question 3

What is anabolic metabolism?

Answer 3

Synthesises larger important cellular components from intermediary metabolises. Uses energy released from catabolism (ATP). Reductive (use H released in catabolism).

Question 4

Name 4 things that fuel molecules are metabolised to supply and an example of each

Answer 4

Building block materials eg amino acids.
Organic precursors eh Acetyl CoA.
Biosynthetic reducing power eg NADH.
Energy for cell function eg ATP.

Question 5

What are the 3 main energy requirements of the body?

Answer 5

Basal metabolic rate.
Activity (muscular work).
Specific dynamic action of food.

Question 6

What type of energy is used predominantly to drive energy requiring activities in the body?

Answer 6

Chemical bond

Question 7

What is an exergonic chemical reaction?

Answer 7

Releases energy.
Spontaneous.
Negative delta G.

Question 8

What is an endergonic chemical reaction?

Answer 8

Requires energy.
Not spontaneous - requires energy input.
Positive delta G.

Question 9

What is an oxidation reaction?

Answer 9

Removal of electrons (or H atoms).

OILRIG.

Question 10

What is a redox reaction?

Answer 10

Oxidation reactions accompanied by a reduction reaction.

Question 11

What are protons transferred to when fuel molecules are oxidised? Give some examples

Answer 11

Carrier molecules.
Eg NAD+ -> NADH + H+.
Eg NADP+ -> NADPH + H+.
Eg FAD -> FADH2.

Question 12

What do carrier molecules act as?

Answer 12

Carriers of reducing power for ATP production and biosynthesis.

Question 13

What are proton carrier molecules made from? How are they converted to their reduced form?

Answer 13

Complex molecules containing components from vitamins (B vitamins).
Converted to their reduced form by adding 2 H atoms.

Question 14

What happens to the protons in reduced proton carrier molecules when placed into a solution?

Answer 14

H+ dissociates

Question 15

By what type of reaction is energy released from food? And what is this used to drive?

Answer 15

Oxidation - exergonic.

ADP + Pi -> ATP.

Question 16

How can energy released as reducing equivalents (electrons or H+) be used to drive energy requiring activities?

Answer 16

Via coupling systems:
Directly - eg use of NADPH in biosynthesis.
Indirectly - eg mitochondrial system to couple NADH to the production of an intermediate energy currency molecule (ATP).

Question 17

Is ATP is a carrier or a store of energy?

Answer 17

Carrier

Question 18

What about ATP enables flow of energy to be controlled?

Answer 18

ATP is stable in the absence of specific catalysts

Question 19

What metabolic pathways are activated when ATP concentration is high?

Answer 19

Anabolic pathways (uses energy released from ATP)

Question 20

What metabolic pathways are activated when ATP concentration is low, and ADP and AMP concentrations are high?

Answer 20

Catabolic pathways

Question 21

What enzyme catalysis the conversion of 2ADP -> ATP + AMP?

Answer 21

Adenylate kinase