Chapter 6: Metabolism--Energy and Enzymes

Question 1

chemical reaction

Answer 1

a process that changes one set of chemicals into another; one substance is changed into another

Question 2

reactants

Answer 2

substances that participate in a chemical reaction

Question 3

products

Answer 3

substances that form as a result of a chemical reaction

Question 4

activation energy

Answer 4

the energy that must be added to cause molecules to react with one another

Question 5

enedothermic

Answer 5

absorbs energy

Question 6

exothermic

Answer 6

releases energy; spontaneous

Question 7

catalyst

Answer 7

a substance that helps a reaction go; not consumed in a chemical reaction and lowers activation energy

Question 8

enzyme

Answer 8

organic molecule; a natural, organic biological catalyst

Question 9

substrates

Answer 9

the reactants in an enzymatic reaction

Question 10

What do chemical reactions always involve?

Answer 10

the breaking of bonds in reactants and the formation of new bonds in products

Question 11

How do chemical reactions that release energy often occur?

Answer 11

spontaneously

Question 12

What reaction will not occur without a source of energy?

Answer 12

reactions that absorb energy

Question 13

What type of reactions are often spontaneous?

Answer 13

exothermic reactions

Question 14

What do cells use enzymes for?

Answer 14

to speed up chemical reactions that take place in cells

Question 15

What happens when a chemical reaction absorbs energy in one direction?

Answer 15

it will release energy in the other direction

Question 16

What factors influence an enzyme’s efficiency?

Answer 16

substrate concentration: increased substrate = increased rate if there is a sufficient enzyme

temperature and pH: increased temperature = increased rate due to increased collisions (to a point); too high temperatures and out of range pH cause an enzyme to denature

enzyme activation: necessary for something to bind and uncover the active site or the production of coenzyme/cofactor to activate

enzyme inhibition: substance is prevented from binding to the active site; feedback inhibition