enzymes

Question 1

what are enzymes

Answer 1

a biological catalyst, usually a protein, that changes the rate of a chemical reaction without being changed themselves

Question 2

what is the purpose of enzymes

Answer 2

they speed up the rate of chemical reactions without being consumed

Question 3

substrate

Answer 3

the reactant that an enzyme acts on when catalyzing a chemical reaction

Question 4

active site

Answer 4

a small part of the enzyme where the substrates will attach to

Question 5

enzyme-substrate complex

Answer 5

when an enzyme and a substrate are joined

Question 6

induced-fit model

Answer 6

chemical interaction between functional groups in the substrate and in the individual amino acids within the enzyme help the enzyme to better accommodate the substrate

Question 7

what is activation energy

Answer 7

the levels of energy required during all chemical reactions

Question 8

how does activation energy change when enzymes are involved

Answer 8

enzymes lower the activation energy of chemical reactions (less energy is needed)

Question 9

cofactor

Answer 9

non-proteins that can bind to an enzyme

Question 10

coenzyme

Answer 10

• responsible for shuttling molecules from one enzyme to another

Question 11

how does the concentration of an enzyme affect the rate of a catalysis reaction

Answer 11

the amount of enzyme is a limiting factor in the rate of the reaction; increase of enzyme speeds up the reaction

Question 12

how does the concentration of a substrate affect the rate of a catalysis reaction

Answer 12

a substrate can increase the rate of the reaction up to a point but ONLY if the enzyme is at an intermediate level

Question 13

how does the pH and temperature affect the rate of a catalysis reaction

Answer 13

the proteins can be denatured; when they lose their shape and and the denaturing agent it removed it is reversible but when the protein is destroyed it is irreversible

Question 14

what is the difference between competitive and noncompetitive inhibition

(2)

Answer 14

competitive: are similar in structure to the substrate and the enzyme inhibitor is able to bind with the active site and block the normal substrate from binding
noncompetitive: enzyme inhibitor attaches to a different site on the enzyme which changes its shape causing the substrate to not bind properly

Question 15

describe feedback inhibition

(4)

Answer 15

• the regulation of a pathway by one of the products of that pathway
• it prevents the waste of cellular resources
• if too much of a product accumulates, it acts as an inhibitor and stops or slows the enzymatic reaction earlier in the process that produces it
• if there isnt enough of the product, inhibition is reduced and the rate of reaction increases