Vocabulary

adhesion

the tendency of a material, such as water, to stick to other materials

ambient temperature

the temperature of the environment

amino acid

an organic molecule that contains a carboxyl group (–COOH), an amino group (–NH2), and a functional side chain, which is a group of atoms that is unique in its structure and function

amino group

a portion of an amino acid made up of a nitrogen atom bonded to two hydrogen atoms (–NH2 )

aqueous solution

a solution containing water

buffer

an aqueous solution that resists changes in pH, containing a weak acid and its conjugate base or a weak base and its conjugate acid

carbohydrate

an organic molecule that contains carbon, hydrogen, and oxygen and provides energy to cells

carboxyl group

a portion of a molecule made of a carbon atom bonded to two oxygen atoms in which one oxygen atom is in turn bonded to a hydrogen atom (-COOH)

cell membrane

the structure that encloses the cell, made of the phospholipid bilayer

cohesion

the tendency of a material, such as water, to stick to itself

deoxyribonucleic acid (DNA)

an organic molecule containing coded instructions for the life processes of an organism, which consists of nucleotides bonded together in the form of a double helix

double helix

the helical structure formed by two strands of DNA as they wind around each other

heat of vaporization

the amount of energy that must be added to a liquid in order to transform it to a gas

lipid

long-chain hydrocarbon that is soluble in nonpolar solvents; that is, solvents without charge

molecule

a group of two or more atoms bonded together

neutral

having a pH of 7

nucleic acid

large molecule made of nucleotides

nucleotide

an organic molecule consisting of a five-carbon sugar, a nitrogen base, and a phosphate group

organic molecule

a molecule that contains at least one carbon atom

organism

a living thing that grows, reproduces, responds to its environment, and uses energy

osmosis

the movement of water molecules across a semipermeable membrane from an area of lower concentration of solute to higher concentration of solute

pH

a measure of the relative proportion of H+ (acid) and OH- (basic) ions in a solution; represented as a number generally ranging from zero (acidic) to 14 (basic), where seven (neutral) represents equal quantities of H+ and OH- ions

phospholipid bilayer

a double layer of lipids and proteins that separates the cell interior from the external environment and regulates the passage of substances into and out of the cell

polar molecule

a molecule that has oppositely charged sides

polymer

a large molecule made of repeating smaller units of similar structure that are bonded together

protein

a large molecule composed of amino acids; proteins speed up reactions and transport material in and out of cells

ribonucleic acid (RNA)

an organic molecule that carries genetic messages out of the nucleus; consists of a single strand of nucleic acids