Key Terms - Apologia Biology Module 2

matter

Anything that has mass and takes up space (has volume).

atomic number

The number of protons in an atom--unique to each type of atom

elements

A collection of atoms that all have the same number of protons

periodic table

A table of chemical elements arranged in order of atomic number

isotopes

One of several forms of an element, each containing the same number of protons but a different number of neutrons

atomic mass

The sum of the protons and neutrons in an atom

molecule

Chemical that results when two or more atoms join together chemically

compound

A molecule that contains atoms of at least two different elements

ionic bond

A chemical bond formed when one or more electrons are transferred from one atom to another

ion

Positively or negatively charged atoms resulting from the transfer of electrons

covalent bond

Chemical bond formed by the sharing of electrons between two or more atoms

polar compound

A molecule in which there is an unequal distribution of the negatively charged electrons causing a partial positive charge at one end and a partial negative charge at the other

hydrogen bond

A weak electrical attraction between a partially positive hydrogen atom and a partially negative atom of another molecule (usually oxygen or nitrogen)

solvent

Any substance in which other substances are dissolved

solute

A dissolved substance

solution

A mixture of solutes dissolved in a solvent

Aqueous solution

A solution in which water is the solvent

cohesion

An attractive force that holds molecules of the same substance together

adhesion

An attractive force that holds molecules of different substances together

Heat capacity

The amount of heat energy required to increase the temperature

Organic molecules

Molecules found in living organisms that contain carbon in rings or long chains, attached to other atoms like hydrogen, oxygen, nitrogen, sulfur, or phosphorus.

Biosynthesis

The process by which living organisms produce larger molecules from smaller ones

Isomers

Two different molecules that have the same chemical formula

monosaccharides

Simple sugars; they are the building blocks of more complex carbohydrates

disaccharides

Carbohydrates that are made up of two monosaccharides

polysaccharides

Carbohydrates that are made up of more than two monosaccharides

Dehydration reaction

A chemical reaction in which molecules combine by removing water

starch

A polysaccharide consisting of many glucose molecules stored in plants

glycogen

A polysaccharide consisting of many glucose molecules stored in animals

cellulose

A polysaccharide consisting of many glucose molecules found in the cell walls of plants

hydrolysis

Breaking down complex molecules by the chemical addition of water

hdryophobic

Lacking any affinity to water, from the latin meaning "water-fearing"

saturated fat

A lipid made from fatty acids that have no double bonds between carbon atoms

unsaturated fat

A lipid made from fatty acids that have at least one double bond between carbon atoms

steroid

Lipid molecules with four fused carbon rings

amino acids

The basic building blocks of proteins each containing a carboxyl group and an amino group

Hydrophilic

Attracts water molecules

Polypeptide

Many amino acids bonded together forming part of a protein or the whole protein

Catalyst

A substance that alters the speed of a chemical reaction but is not used up in the process

Activation energy

The energy needed to get reactions started

Active site

Area of an enzyme to which a specific substrate fits

Substrate

A specific reactant acted on by an enzyme

Denaturation

The process in which the normal shape of a protein is lost, usually due to heat

Nucleotides

The building blocks of DNA and RNA