Unit 6 - Metabolic Pathways

Question 1

what is a metabolic pathway

Answer 1

Metabolic Pathways are integrated and controlled pathways of enzyme-catalysed reactions in a cell

Question 2

Is a metabolic pathway limited to just irreversible routes

Answer 2

metabolic pathways can have reversible, irreversible and alternative routes

Question 3

what are reactions within a metabolic pathway called

Answer 3

reactions within a metabolic pathway can be anabolic or catabolic

Question 4

what are Anabolic reactions

Answer 4

Anabolic reactions are reactions which build up large molecules from small molecules and require energy

Question 5

what are Catabolic reactions

Answer 5

Catabolic reactions are reactions which breakdown large molecules into smaller molecules and release energy

Question 6

what are metabolic pathways controlled by

Answer 6

metabolic pathways are controlled by the presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes

Question 7

what is affinity in terms of an active site

Answer 7

affinity is the force of attraction of a substrate to an enzymes active site

Question 8

what does induced fit mean

Answer 8

induced fit occurs when the active site changes shape to better fit the substrate after the substrate binds

Question 9

what happens to affinity before and after binding with the active site

Answer 9

the substrate molecules have a high affinity for the active site and the subsequent products have a low affinity allowing them to leave the active site

Question 10

how are metabolic pathways altered

Answer 10

some metabolic reactions are reversible and the presence of a substrate or the removal of a product will drive a sequence of reactions in a particular direction.

Question 11

what are competitive inhibitors

Answer 11

competitive inhibitors bind at the active site preventing the substrate from binding

Question 12

how can competitive inhibitors be reversed

Answer 12

competitive inhibitors can be reversed by increasing substrate concentration

Question 13

what are non-competitive inhibitors

Answer 13

non-competitive inhibitors bind away from the active site but change the shape of the active site preventing the substrate from binding

Question 14

how can non-competitive inhibitors be reversed

Answer 14

non-competitive inhibitors cannot be reversed, not even by increasing substrate concentration.

Question 15

what is feedback inhibition

Answer 15

feedback inhibition is occurs when the end-product in the metabolic pathway reaches a critical condition

Question 16

what occurs in feedback inhibition

Answer 16

The end-product inhibits an earlier enzyme, blocking the pathway, and so prevent further synthesis of the end-product