Chapter 2: The Chemical Level of Organization

adenine

A nitrogen- containing base: , cytosine, guanine, thymine, or uracil.

Galactose

Five monosaccharides are important in the body: Glucose, Fructose, , Deoxyribose, Ribose.

valence shell

If the is not full, the atom is reactive; meaning it will tend to react with other atoms in ways that make the full.

dehydrationsynthesis

They are involved in and hydrolysis reactions.

Warm core blood

cools the surroundings in skin blood vessels.

organic compound

A(n) , then, is a substance that contains both carbon and hydrogen.

element

is a pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means.

compound

is a substance composed of two or more elements joined by chemical bonds.

atom

is the smallest quantity of an element that retains the unique properties of that element.

Atomic number

which is the number of protons in the nucleus of the atom, identifies the element.

It is always composed of the same three elements

carbon, hydrogen, and oxygen

Atoms are made up of even smaller subatomic particles, three types of which are important

the proton, neutron, and electron

Two types of chemical reactions involve the creation or the consumption of water

dehydration synthesis and hydrolysis

Five monosaccharides are important in the body

Glucose, Fructose, Galactose, Deoxyribose, Ribose

Disaccharides (di

= "two") are made up of two monomers

A pentose sugar

either deoxyribose or ribose

A nitrogen-containing base

adenine, cytosine, guanine, thymine, or uracil

Mass number

is the sum of the number of protons and neutrons in its nucleus

Periodic table of the elements

is a chart identifying the 92 elements found in nature, as well as several larger, unstable elements discovered experimentally.

isotope

is one of the different forms of an element, distinguished from one another by different numbers of neutrons.

radioactive isotope

is an isotope whose nucleus readily decays, giving off subatomic particles and electromagnetic energy. 

electron shell

is a layer of electrons that encircle the nucleus at a distinct energy level.

valence shell

is an atom’s outermost electron shell.

bond

is a weak or strong electrical attraction that holds atoms in the same vicinity.

molecule

A more or less stable grouping of two or more atoms held together by chemical bonds is called a

chemical compound

When a molecule is made up of two or more atoms of different elements, it is called a

ion

An atom that has an electrical charge—whether positive or negative—is an

cation

A positively charged ion is known as a

anion

A negatively charged ion is known as an

ionic bond

is an ongoing, close association between ions of opposite charg

hydrogen bond

is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another molecule.

kinetic energy

is the form of energy powering any type of matter in motion.

Potential energy

is the energy of position, or the energy matter possesses because of the positioning or structure of its components.

Chemical energy

is the form of potential energy in which energy is stored in chemical bonds.

product

The one or more substances produced by a chemical reaction are called the

synthesis reaction

is a chemical reaction that results in the synthesis (joining) of components that were formerly separate.

decomposition reaction

is a chemical reaction that breaks down or “de-composes” something larger into its constituent parts.

exchange reaction

is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both formed and broken, and chemical energy is absorbed, stored, and released. 

catalyst

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

enzyme

is a catalyst composed of protein or ribonucleic acid (RNA).

chemical reaction

activation energy is the “threshold” level of energy needed to break the bonds in the reactants.

inorganic compound

is a substance that does not contain both carbon and hydrogen.

organic compound

is a substance that contains both carbon and hydrogen.

mixture

is a combination of two or more substances, each of which maintains its own chemical identity.

solute

A liquid solution consists of a solvent that dissolves a substance called a

hydrophobic

Nonpolar molecules, which do not readily dissolve in water, are called

colloid

is a mixture that is somewhat like a heavy solution.

suspension

is a liquid mixture in which a heavier substance is suspended temporarily in a liquid, but over time, settles out.

Dehydration synthesis

is a type of chemical reaction in which two molecules are joined together by the removal of a water molecule.

Hydrolysis

is a chemical reaction in which a molecule is broken down into two parts by the addition of a molecule of water.

acid

is a substance that releases hydrogen ions (H+) in solution.

base

is a substance that releases hydroxyl ions (OH–) in solution, or one that accepts H+ already present in solution.

buffer

is a solution of a weak acid and its conjugate base. 

functional group

is a group of atoms linked by strong covalent bonds and tending to function in chemical reactions as a single unit.

carbohydrate

is a molecule composed of carbon, hydrogen, and oxygen; in most carbohydrates, hydrogen and oxygen are found in the same two-to-one relative proportions they have in water.

Monosaccharides

are the monomers of carbohydrates.

Disaccharides

(di- = “two”) are made up of two monomers.

Polysaccharides

are the polymers, and can consist of hundreds to thousands of monomers.

Adenosine triphosphate (ATP)

is composed of a ribose sugar, an adenine base, and three phosphate groups.

lipid

is one of a highly diverse group of compounds made up mostly of hydrocarbons

triglyceride

is one of the most common dietary lipid groups, and the type found most abundantly in body tissues.

phospholipid

is a bond between the glycerol component of a lipid and a phosphorus molecule.

steroid

compound (referred to as a sterol) has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules.

protein

is an organic molecule composed of amino acids linked by peptide bonds.

amino acid

An ___ is a molecule composed of an amino group and a carboxyl group, together with a variable side chain.

peptide bond

A ___ is a covalent bond between two amino acids that forms by dehydration synthesis.

disulfide bond

A __ is a covalent bond between sulfur atoms in a polypeptide.

Denaturation

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

substrate

is a reactant in an enzymatic reaction.

Deoxyribonucleic acid (DNA)

is a nucleotide that stores genetic information.

Ribonucleic acid (RNA)

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

purine

A ___ is a nitrogen-containing molecule with a double ring structure, which accommodates several nitrogen atoms.

pyramidine

A ___ is a nitrogen-containing base with a single ring structure.

Phosphorylation

is the addition of a phosphate group to an organic compound, in this case, resulting in ATP.