Biology. Chapt 2

Front 1

What is an Atom?

Back 1

the basic unity of a chemical element

Front 2

What is a Molecule?

Back 2

a group of atoms bonded together

Front 3

What is an isotope?

Back 3

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.

Front 4

What is an electron?

Back 4

a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

Front 5

What is a proton?

Back 5

a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.

Front 6

Atomic #?

Back 6

the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.

Front 7

Atomic Mass?

Back 7

the mass of an atom of a chemical element expressed in atomic mass units.

Front 8

Compound?

Back 8

a thing that is composed of two or more separate elements; a mixture : the air smelled like a compound of diesel and gasoline fumes.
• (also chemical compound) a substance formed from two or more elements chemically united in fixed proportions : a compound of hydrogen and oxygen.

Front 9

Covalent bond

Back 9

of, relating to, or denoting chemical bonds formed by the sharing of electrons between atoms

Front 10

valence electron?

Back 10

the combining power of an element, esp. as measured by the number of hydrogen atoms it can displace or combine with : carbon always has a valence of 4.

Front 11

ionic bond

Back 11

• (of a chemical bond) formed by the electrostatic attraction of oppositely charged ions.

Front 12

hydrogen bond

Back 12

a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.

Front 13

mixture

Back 13

a substance made by mixing other substances together

Front 14

solution

Back 14

a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).
• the process or state of being dissolved in a solvent.

Front 15

solute

Back 15

the minor component in a solution, dissolved in the solvent.

Front 16

solvent

Back 16

the liquid in which a solute is dissolved to form a solution.
• a liquid, typically one other than water, used for dissolving other substances.

Front 17

suspension

Back 17

a mixture in which particles are dispersed throughout the bulk of a fluid : a suspension of corn starch in peanut oil.

Front 18

pH scale

Back 18

The pH scale measures how acidic or basic a substance is.

Front 19

acid

Back 19

a chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind : rainwater is a very weak acid | traces of acid. Often contrasted with

Front 20

base

Back 20

a substance capable of reacting with an acid to form a salt and water, or (more broadly) of accepting or neutralizing hydrogen ions. Compare with alkali .
• Biochemistry a purine or pyrimidine group in a nucleotide or nucleic acid.

Front 21

alkaline solution?

Back 21

having the properties of an alkali, or containing alkali; having a pH greater than 7. Often contrasted with acid or acidic ; compare with basic .

Front 22

starch?

Back 22

powder or spray made from this substance and used before ironing to stiffen fabric or clothing.

Front 23

reactant?

Back 23

a substance that takes part in and undergoes change during a reaction.

Front 24

product?

Back 24

a substance produced during a natural, chemical, or manufacturing process

Front 25

chemical reaction?

Back 25

relating to, involving, or denoting the use of poison gas or other chemicals as weapons of war : the manufacture of chemical weapons.

Front 26

catayst?

Back 26

a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

Front 27

enzyme?

Back 27

a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

Front 28

substrate

Back 28

a substance or layer that underlies something, or on which some process occurs, in particular
• the surface or material on or from which an organism lives, grows, or obtains its nourishment.
• the substance on which an enzyme acts.
• a material that provides the surface on which something is