Biology Chapter 5 Vocabulary

Front 1

energy

Back 1

the capacity to cause change, especially to perform work

Front 2

entropy

Back 2

a measure of disorder; one form of disorder is heat, which is random molecular motion

Front 3

energy coupling

Back 3

in cellular metabolism, the use of energy released from an exergonic reaction to drive an endergonic reaction

Front 4

enzyme

Back 4

a macromolecule, usually a protein, that serves as a biological catalyst, changing the rate of a chemical reaction without being consumed by the reaction

Front 5

activation energy

Back 5

the amount of energy that reactants must absorb before a chemical reaction reaction will start

Front 6

kinetic energy

Back 6

the energy of motion; the energy of a mass of matter that is moving; moving matter does work by imparting motion to other matter

Front 7

endergonic reaction

Back 7

an energy-requiring chemical reaction, which yields products with more potential energy than the reactants; the amount of energy stored in the products equals the difference between the potential energy in the reactants and that in the products

Front 8

ATP

Back 8

adenosine triphosphate, the main energy source for cells

Front 9

exergonic reaction

Back 9

an energy-releasing chemical reaction in which the reactants contain more potential energy than the products; the reaction releases an amount of energy equal to the difference in potential energy between the reactants and the products

Front 10

cellular metabolism

Back 10

all the chemical activities of a cell

Front 11

active site

Back 11

the part of an enzyme molecule where a substrate molecule attaches (by means of weak chemical bonds); typically, a pocket or groove on the enzyme's surface

Front 12

induced fit

Back 12

the change in shape of the active site of an enzyme, caused by entry of the substrate, so that it binds more snugly to the substrate

Front 13

heat

Back 13

thermal energy; the amount of energy associated with the movement of the atoms and molecules of the atoms and molecules in a body of matter; energy in its most random form

Front 14

potential energy

Back 14

the energy that matter possesses because of its location or arrangement

Front 15

First Law of Thermodynamics

Back 15

energy in the universe is constant

Front 16

Second Law of Thermodynamics

Back 16

energy conversions increase the disorder of the universe

Front 17

phosphorylation

Back 17

the transfer of a phosphate group, usually from ATP, to a molecule; nearly all cellular work depends on ATP energizing other molecules by this

Front 18

substrate

Back 18

a surface in or on which an organism lives

Front 19

signal transduction pathway

Back 19

in cell biology, a series of molecular changes that converts a signal on a target cell's surface to a specific response inside the cell

Front 20

noncompetitive inhibitor

Back 20

a substance that reduces the activity of an enzyme without entering an active site; changes the shape of the the enzyme so that the active site no longer effectively catalyzes the conversion of substrate to product

Front 21

competitive inhibitor

Back 21

a substance that reduces the activity of an enzyme by binding to the enzyme's active site in place of the substrate; its structure mimics that of the enzyme's substrate