Chapter 8 - Metabolism

Question 1

What kind of reaction is metabolism?

Answer 1

A biochemical reaction

Question 2

Metabolism (3)

Answer 2

1. the totality of an organisms chemical reactions
2. the emergent property of life that arises from interaction between molecules
3. Metabolic pathways of life form a large network

Question 3

Metabolic Pathways (2)

Answer 3

1. begins with specific molecules called reactants and ends with the formation of products
2. Each biochemical reaction is catalyzed by a specific enzyme.

Question 4

Two main types of metabolic pathways:

Answer 4

Anabolic and Catabolic

Question 5

Catabolic

Answer 5

Breaks down complex molecules into simpler compounds. These reactions release energy.

Complex mols -> smaller mols + energy

Question 6

Anabolic

Answer 6

Builds complex molecules from simpler ones. These reactions consume energy.

Small mols + energy -> larger molecules

Question 7

How do you know if a reaction releases or consumes energy

Answer 7

Free Energy (Change in G). Does not tell us anything about the rate of a reaction.

Change = G products - G reactants

look at graphs in notes

Question 8

What increases a reaction rate (3)

Answer 8

Enzymes (they act as a catalyst)

• they are not consumed by the reaction
• reactants (substrates) contort into unstable configuration (transition state)
• Requires energy (activation energy)

Question 9

Activation Energy

Answer 9

A small amount of energy to get reactants into a more unstable state (transition state). Enzymes can lower activation energy by inducing the transition state.
see graphs

Question 10

General Properties of Enzymes (4)

Answer 10

• proteins
• each has a unique 3D shape
• substrates (specific reactants) bind to an enzymes active site (pocket on the surface)

Question 11

Induced Fit

Answer 11

When a substrate fits into an active site. Old bonds break and new bonds form, changing the enzymes shape.

Question 12

How do enzymes induce the transition state? (3)

Answer 12

1. Bringing reactant molecules together
   - reduces reliance on random collisions.
2. Changing/distorting shape of substrate molecules
3. Exporting the reactant to altered chemically (charged) environment to promote catalyst.
   - properties of amino acids in active site determine favourability of environment

Question 13

Enzyme Inhibitors (3)

Answer 13

1. Influenced by the cellular environment
2. physical factors influence enzyme activity
3. temperature, salt concentration, pH