chapter 6

Question 1

Metabolism

Answer 1

The totality of an organisms chemical reactions.

Question 2

Metabolic Pathways

Answer 2

Begin with a specific molecule and ends with a product. Each step is catalyzed by a specific enzyme.

Question 3

Catabolic Pathways

Answer 3

Release energy by breaking down complex molecules into simpler molecules.

Question 4

Anabolic Pathways

Answer 4

Consume energy to build complex molecules from simpler ones.

Question 5

Bioenergetics

Answer 5

The study of how energy flows through living organisms.

Question 6

Work

Answer 6

The movement of matter against opposing forces.

Question 7

Thermodynamics

Answer 7

The study of energy transformations.

Question 8

1st law of thermodynamics

Answer 8

Energy can be transferred and transformed but it cannot be created or destroyed.

Question 9

2nd law of thermodynamics

Answer 9

Entropy can only increase or stay the same in a closed system.

Question 10

Entropy

Answer 10

A measure of molecular disorder.

Question 11

Spontaneous Processes

Answer 11

Occur without energy input. Must increase the entropy of the universe and be moving towards equilibrium.

Question 12

Free Energy

Answer 12

The portion of a system’s energy that can do work when temperature and pressure are uniform throughout, as in a living cell. A measure of a systems instability.

Question 13

Exergonic Reaction

Answer 13

Proceeds with a net release of free energy and is spontaneous.

Question 14

Endergonic Reaction

Answer 14

Absorbs free energy from its surroundings and is nonspontaneous.

Question 15

Energy Coupling

Answer 15

The use of an exergonic reaction to drive an endergonic one. How cells do work.

Question 16

ATP (adenosine triphosphate)

Answer 16

Composed of a ribose (a sugar), adenine (a nitrogen base), and a chain of three phosphate groups.

Question 17

Phosphorylation

Answer 17

Transferring a phosphate group to another molecule, such as a reactant.

Question 18

Catalyst

Answer 18

A chemical agent that speeds up a reaction without being consumed by the reaction.

Question 19

Enzyme

Answer 19

A macromolecule that acts as a catalyst. Most are proteins.

Question 20

Activation Energy

Answer 20

The energy required to start a reaction by breaking bonds in the reactant molecules.

Question 21

Substrate

Answer 21

The reactant molecule on which an enzyme acts.

Question 22

Active Site

Answer 22

The region on the enzyme to which the substrate binds.

Question 23

Induced Fit

Answer 23

Enzymes change shape due to chemical interactions with the substrate. Brings chemical groups of the active site together.

Question 24

Enzyme Inhibition

Answer 24

Enzyme activity is regulated by molecules that selectively inhibit enzyme function.

Question 25

Competitive Inhibitors

Answer 25

Bind to the active site of an enzyme and prevent the substrate from binding.

Question 26

Noncompetitive Inhibitors

Answer 26

Bind to an alternate site on the enzyme, causing the active site to change shape and become less effective.

Question 27

Allosteric Regulation

Answer 27

May either inhibit or stimulate an enzyme’s activity. Occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site.