Chapter 2 Key Terms

Question 1

compound that releases hydrogen ions (H+) in solution

Answer 1

acid

Question 2

amount of energy greater than the energy contained in the reactants, which must be overcome for a
reaction to proceed

Answer 2

activation energy

Question 3

nucleotide containing ribose and an adenine base that is essential in energy transfer

Answer 3

adenosine triphosphate (ATP)

Question 4

building block of proteins; characterized by an amino and carboxyl functional groups and a variable sidechain

Answer 4

amino acid

Question 5

atom with a negative charge

Answer 5

anion

Question 6

smallest unit of an element that retains the unique properties of that element

Answer 6

atom

Question 7

number of protons in the nucleus of an atom

Answer 7

atomic number

Question 8

compound that accepts hydrogen ions (H+) in solution

Answer 8

base

Question 9

electrical force linking atoms

Answer 9

bond

Question 10

solution containing a weak acid or a weak base that opposes wide fluctuations in the pH of body fluids

Answer 10

buffer

Question 11

class of organic compounds built from sugars, molecules containing carbon, hydrogen, and oxygen in a
1-2-1 ratio

Answer 11

carbohydrate

Question 12

substance that increases the rate of a chemical reaction without itself being changed in the process

Answer 12

catalyst

Question 13

atom with a positive charge

Answer 13

cation

Question 14

form of energy that is absorbed as chemical bonds form, stored as they are maintained, and released as they are broken

Answer 14

chemical energy

Question 15

liquid mixture in which the solute particles consist of clumps of molecules large enough to scatter light

Answer 15

colloid

Question 16

substance composed of two or more different elements joined by chemical bonds

Answer 16

compound

Question 17

number of particles within a given space

Answer 17

concentration

Question 18

chemical bond in which two atoms share electrons, thereby completing their valence shells

Answer 18

covalent bond

Question 19

type of catabolic reaction in which one or more bonds within a larger molecule are broken, resulting in the release of smaller molecules or atoms

Answer 19

decomposition reaction

Question 20

change in the structure of a molecule through physical or chemical means

Answer 20

denaturation

Question 21

deoxyribose-containing nucleotide that stores genetic information

Answer 21

deoxyribonucleic acid (DNA)

Question 22

pair of carbohydrate monomers bonded by dehydration synthesis via a glycosidic bond

Answer 22

disaccharide

Question 23

covalent bond formed within a polypeptide between sulfide groups of sulfur-containing amino acids, for example, cysteine

Answer 23

disulfide bond

Question 24

subatomic particle having a negative charge and nearly no mass; found orbiting the atom’s nucleus

Answer 24

electron

Question 25

area of space a given distance from an atom’s nucleus in which electrons are grouped

Answer 25

electron shell

Question 26

substance that cannot be created or broken down by ordinary chemical means

Answer 26

element

Question 27

protein or RNA that catalyzes chemical reactions

Answer 27

enzyme

Question 28

type of chemical reaction in which bonds are both formed and broken, resulting in the transfer of components

Answer 28

exchange reaction

Question 29

group of atoms linked by strong covalent bonds that tends to behave as a distinct unit in chemical reactions with other atoms

Answer 29

functional group

Question 30

dipole-dipole bond in which a hydrogen atom covalently bonded to an electronegative atom is weakly attracted to a second electronegative atom

Answer 30

hydrogen bond

Question 31

substance that does not contain both carbon and hydrogen

Answer 31

inorganic compound

Question 32

atom with an overall positive or negative charge

Answer 32

ion

Question 33

attraction between an anion and a cation

Answer 33

ionic bond

Question 34

one of the variations of an element in which the number of neutrons differ from each other

Answer 34

isotope

Question 35

energy that matter possesses because of its motion

Answer 35

kinetic energy

Question 36

class of nonpolar organic compounds built from hydrocarbons and distinguished by the fact that they are not soluble in water

Answer 36

lipid

Question 37

large molecule formed by covalent bonding

Answer 37

macromolecule

Question 38

sum of the number of protons and neutrons in the nucleus of an atom

Answer 38

mass number

Question 39

physical substance; that which occupies space and has mass

Answer 39

matter

Question 40

two or more atoms covalently bonded together

Answer 40

molecule

Question 41

monomer of carbohydrate; also known as a simple sugar

Answer 41

monosaccharide

Question 42

heavy subatomic particle having no electrical charge and found in the atom’s nucleus

Answer 42

neutron

Question 43

class of organic compounds composed of one or more phosphate groups, a pentose sugar, and a base

Answer 43

nucleotide

Question 44

substance that contains both carbon and hydrogen

Answer 44

organic compound

Question 45

covalent bond formed by dehydration synthesis between two amino acids

Answer 45

peptide bond

Question 46

arrangement of the elements in a table according to their atomic number; elements having similar properties because of their electron arrangements compose columns in the table, while elements having the same number of valence shells compose rows in the table

Answer 46

periodic table of the elements

Question 47

negative logarithm of the hydrogen ion (H+) concentration of a solution

Answer 47

pH

Question 48

a lipid compound in which a phosphate group is combined with a diglyceride

Answer 48

phospholipid

Question 49

addition of one or more phosphate groups to an organic compound

Answer 49

phosphorylation

Question 50

molecule with regions that have opposite charges resulting from uneven numbers of electrons in the nuclei of the atoms participating in the covalent bond

Answer 50

polar molecule

Question 51

compound consisting of more than two carbohydrate monomers bonded by dehydration synthesis via glycosidic bonds

Answer 51

polysaccharide

Question 51

compound consisting of more than two carbohydrate monomers bonded by dehydration synthesis via glycosidic bonds

Answer 51

polysaccharide

Question 52

stored energy matter possesses because of the positioning or structure of its components

Answer 52

potential energy

Question 53

one or more substances produced by a chemical reaction

Answer 53

product

Question 54

lipid compound derived from fatty acid chains and important in regulating several body processes

Answer 54

prostaglandin

Question 55

class of organic compounds that are composed of many amino acids linked together by peptide bonds

Answer 55

protein

Question 56

heavy subatomic particle having a positive charge and found in the atom’s nucleus

Answer 56

proton

Question 57

nitrogen-containing base with a double ring structure; adenine and guanine

Answer 57

purine

Question 58

nitrogen-containing base with a single ring structure; cytosine, thiamine, and uracil

Answer 58

pyrimidine

Question 59

unstable, heavy isotope that gives off subatomic particles, or electromagnetic energy, as it decays; also called radioisotopes

Answer 59

radioactive isotope

Question 60

one or more substances that enter into the reaction

Answer 60

reactant

Question 61

ribose-containing nucleotide that helps manifest the genetic code as protein

Answer 61

ribonucleic acid (RNA)

Question 62

homogeneous liquid mixture in which a solute is dissolved into molecules within a solvent

Answer 62

solution

Question 63

(also, sterol) lipid compound composed of four hydrocarbon rings bonded to a variety of other atoms and molecules

Answer 63

steroid

Question 64

reactant in an enzymatic reaction

Answer 64

substrate

Question 65

liquid mixture in which particles distributed in the liquid settle out over time

Answer 65

suspension

Question 66

type of anabolic reaction in which two or more atoms or molecules bond, resulting in the formation of a larger molecule

Answer 66

synthesis reaction

Question 67

lipid compound composed of a glycerol molecule bonded with three fatty acid chains

Answer 67

triglyceride

Question 68

outermost electron shell of an atom

Answer 68

valence shell