8.1 Metabolism

Question 1

Enzymes

Answer 1

Substrate binds to active site to be split or binded

Lower activation energy required

Question 2

Enzyme inhibitors

Answer 2

Competative vs non-competative

Competative blocks active site

Non-competative binds to allosteric side to change the shape of the active site

Question 3

End product inhibitation

Answer 3

A negative feedback used to regulate the production of a given molecule.

End product combines with with first enzyme

Question 4

Metabolism

Answer 4

describes the sum total of all reactions that occur within an organism in order to maintain life

Question 5

activation energy

Answer 5

Enzymes speed up the rate of a biochemical reaction by lowering the activation energy

The certain amount of energy in order to proceed in a reaction.

exergonic = energy released into system
endergonic = lost to the system

Question 6

End-product inhibition of the pathway that converts threonine to isoleucine

Answer 6

Isoleucine is an essential amino acid, meaning it is not synthesised by the body in humans

In plants and bacteria, isoleucine may be synthesised from threonine in a five-step reaction pathway

• In the first step of this process, threonine is converted into an intermediate compound by an enzyme (threonine deaminase)
• Isoleucine can bind to an allosteric site on this enzyme and function as a non-competitive inhibitor
• This feedback inhibition ensures that isoleucine production does not cannibalise available stocks of threonine

Question 7

Factors Affecting Enzyme Activity

Answer 7

Question 8

The Effect of Inhibition on Enzyme Kinetics

Answer 8

Competitive and non-competitive inhibitors effect the kinetics of an enzyme-catalysed reaction in different ways:
Both reduce the rate of reaction by limiting the amount of uninhibited enzyme available for reaction

Question 9

Metabolic pathways

Answer 9

typically organised into chains or cycles of enzyme-catalysed reactions
Examples of chains: Glycolysis
Examples of cycles: Krebs cycle