Biology chapter 2

Question 1

acid

Answer 1

a substance that donates hydrogen ions and therefore lowers pH

Question 2

adhesion

Answer 2

the attraction between water molecules and molecules of a different substance

Question 3

anion

Answer 3

a negative ion formed by gaining electrons

Question 4

base

Answer 4

a substance that absorbs hydrogen ions and therefore raises pH

Question 5

buffer

Answer 5

a solution that resists a change in pH by absorbing or releasing hydrogen or hydroxide ions

Question 6

cation

Answer 6

a positive ion formed by losing electrons

Question 7

chemical bond

Answer 7

an interaction between two or more of the same or different elements that results in the formation of molecules

Question 8

cohesion

Answer 8

the intermolecular forces between water molecules caused by the polar nature of water; creates surface tension

Question 9

covalent bond

Answer 9

a type of strong bond between two or more of the same or different elements; forms when electrons are shared between elements

Question 10

deoxyribonucleic acid (DNA)

Answer 10

a double-stranded polymer of nucleotides that carries the hereditary information of the cell

Question 11

electron

Answer 11

a negatively charged particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a charge of –1

Question 12

electron transfer

Answer 12

the movement of electrons from one element to another

Question 13

Enzyme

Answer 13

a catalyst in a biochemical reaction that is usually a complex or conjugated protein

Question 14

hormone

Answer 14

a chemical signaling molecule, usually a protein or steroid, secreted by an endocrine gland or group of endocrine cells; acts to control or regulate specific physiological processes

Question 15

hydrophilic

Answer 15

describes a substance that dissolves in water; water-loving

Question 16

hydrophobic

Answer 16

describes a substance that does not dissolve in water; water-fearing

Question 17

ion

Answer 17

an atom or compound that does not contain equal numbers of protons and electrons, and therefore has a net charge

Question 18

ionic bond

Answer 18

a chemical bond that forms between ions of opposite charges

Question 19

isotope

Answer 19

one or more forms of an element that have different numbers of neutrons

Question 20

neutron

Answer 20

a particle with no charge that resides in the nucleus of an atom; has a mass of 1

Question 21

non polar covalent bond

Answer 21

a type of covalent bond that forms between atoms when electrons are shared equally between atoms, resulting in no regions with partial charges as in polar covalent bonds

Question 22

octet rule

Answer 22

states that the outermost shell of an element with a low atomic number can hold eight electrons

Question 23

polar covalent bond

Answer 23

a type of covalent bond in which electrons are pulled toward one atom and away from another, resulting in slightly positive and slightly negative charged regions of the molecule

Question 24

polypeptide

Answer 24

a long chain of amino acids linked by peptide bonds

Question 25

proton

Answer 25

a positively charged particle that resides in the nucleus of an atom; has a mass of 1 and a charge of +1

Question 26

saturated fatty acid

Answer 26

a long-chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized

Question 27

solvent

Answer 27

a substance capable of dissolving another substance