Enzymes & metabolism

Question 1

what steps can metabolic pathways have?

Answer 1

reversible steps, irreversible steps and alternative routes

Question 2

describe anabolic reactions

Answer 2

build up of large molecules from small molecules

Question 3

describe catabolic reactions

Answer 3

the break down of large molecules into smaller molecules

Question 4

what term can be used to describe a reaction that releases energy?

Answer 4

catabolic

Question 5

what term can be used to describe a reaction that requires energy

Answer 5

anabolic

Question 6

describe activation energy

Answer 6

the energy to start a reaction

Question 7

explain the term specific when applied to enzymes

Answer 7

an enzyme can only act on one substrate

Question 8

where does a substrate attach on an enzyme?

Answer 8

the substrate attached to the active site on the enzyme

Question 9

describe the substrate molecules affinity for the active site

Answer 9

high

Question 10

describe induced fit

Answer 10

the active site changes shape to better fit the substrate after the substrate binds

Question 11

what effect does induced fit have in the activation energy required for the reaction to occur

Answer 11

lowers it

Question 12

describe the products affinity for the active site

Answer 12

the products have a low affinity allowing them to leave the active site

Question 13

describe the relationship between increasing substrate concentration and reaction rate

Answer 13

as the substrate concentration increases the reaction rate increases until it plateaus

Question 14

why will the reaction rate plateau despite the substrate concentration still increasing

Answer 14

the enzyme concentration has become a limiting factor as all the active sites are occupied

Question 15

what word is used to describe a chemical which decrease the rate of a reaction?

Answer 15

inhibitor

Question 16

describe the action of a competitive inhibitor

Answer 16

bind at the active site preventing the substrate from binding

Question 17

describe the action of a non-competitive inhibitor

Answer 17

bind away from the active site but change the shape of the active site preventing the substrate from binding

Question 18

which type of enzyme inhibitor can be reversed by increasing substrate concentration

Answer 18

competitive inhibitor. non-competitive inhibition cannot be reversed by increasing substrate concentration

Question 19

describe feedback inhibition

Answer 19

when the end product of a series of reactions bind to an enzyme that catalyses a reaction early in the pathway, blocking the pathway