A&P 1 - Mod 2-Chemical Level of Organization

Matter

Anything that takes up space and has mass.

Mass

The measurement of matter in an item.

Atom

The smallest unit of matter able to take part in a chemical reaction.

Proton

A subatomic particle with a positive charge and 1 mass unit, located in the atomic nucleus.

Neutron

A subatomic particle with a neutral charge and 1 mass unit, located in the atomic nucleus.

Electron

A subatomic particle with a negative charge and 0 mass units, located in the electron shell.

Nucleus

The deep, central region of an atom containing protons and often neutrons.

Electron Cloud

The duperficial, outer region of an atom containing electrons.

Element

A substance made purely of one type of atom.

Atomic Symbol

A one or two letter abbreviation for an atom.

Atomic Number

The number of protons located in an atom.

Atomic Mass

The total mass of an individual atom.

Atomic Weight

The weighted average mass of all atoms of an element.

Ion

An atom with an abnormal number of electrons.

Isotope

An atom with an abnormal number of neutrons.

Cation

An atom with a positive charge due to 1+ missing electron(s).

Anion

An atom with a negative charge due to 1+ extra electron(s).

Bond

A connection between atoms involving the sharing or transfer of electrons.

Electron Shells

Defined spaces away from the atomic nucleus in which a defined number of electrons can reside.

Valence Shell

The outer most electron shell of an atom.

Ionic Bond

A chemical interaction between atoms where one or more electrons are transferred creating a cation and anion which then associate by electrical forces.

Covalent Bond

A chemical interaction between atoms where one or more sets of electrons are shared between two or more atoms.

Hydrogen Bond

A chemical interaction between a slightly positive hydrogen and slightly negative O, N, or F atom.

Single Bond

A covalent bond where one set of electrons are shared.

Double Bond

A covalent bond where two sets of electrons are shared.

Triple Bond

A covalent bond where three sets of electrons are shared.

Non-Polar Covalent Bond

A covalent bond where electrons are shared equally and the molecule or compound is non-charged.

Polar Covalent Bond

A covalent bond where electrons are not shared equally between atoms and the molecule or compound is slightly charged at opposite ends of the bond.

Molecule

A chemical structure formed by covalent bonds.

Compound

A chemical structure composed of two or more unique atoms in a fixed proportion.

Solid

A state of matter which maintains volume and shape within normal environmental ranges.

Liquid

A state of matter which maintains volume but not shape within normal environmental ranges.

Gas

A state of matter which maintains neither volume or shape within normal environmental ranges.

Metabolism

The sum total of all chemical reactions within a defined entity (i.e. cell, tissue, organism).

Reactant

A substance that undergoes change during a chemical reaction.

Product

A substance that is produced in a chemical reaction.

Chemical Reaction

An interaction between atoms which causes reactants to be altered and products to be produced.

Decomposition Reaction

A chemical reaction where one or more reactants are broken into smaller components.

Synthesis Reaction

A chemical reaction where two or more reactants are bonded together to create a single product.

Exchange Reaction

A chemical reactino where reactants are broken down and the components are rearranged to produce new products.

Catabolism

The sum total of all decomposition reactions within a defined entity (i.e. cell, tissue, organism).

Anabolism

The sum total of all synthesis reactions within a defined entity (i.e. cell, tissue, organism).

Hydrolysis

A decomposition reaction in which water is used to break down the reactant and the components of water are added to the resulting products.

Dehydration Synthesis

A synthesis reaction where water is removed from reactants in forming a new bond.

Activation Energy

The amount of energy required by reactants to initiate a chemical reaction.

Enzyme

A chemical (most often protein) that lowers the activation energy of a specific reaction.

Exergonic

A chemical reaction that releases energy.

Endergonic

A chemnical reaction that takes in energy.

Solvent

The component of a solution that dissolves the solute.

Solute

The component of a solution that is dissolved into the solvent.

Solution

A homogenous mixture of a solvent and solute.

Density

The measurement of mass per unit volume.

Electrolytes

A liquid that contains ions.

Hydrophobic

A substances that does not mix with water.

Hydrophilic

A substances that does mix with water.

pH

A scale measuring the acidity or basicity of a substanced based on the concentration of hydrogen (H+) and hydroxide (OH-) ions.

Acid

A substance with a measured pH less than 7 and a greater relative concentration of hydrogen (H+) to hydroxide (OH-).

Base

A substance with a measured pH greater than 7 and a lower relative concentration of hydrogen (H+) to hydroxide (OH-).

Neutral

A substance with a measured pH of 7 and an equal relative concentration of hydrogen (H+) to hydroxide (OH-).

Buffer

A substance that resists changes in pH by accepting or donating hydrogen ions (H+).

Organic

A substance that contains carbon in covalent bonds.

Inorganic

A substance that does not contain carbon.

Monomer

A single subunit.

Dimer

Two subunits bonded together.

Polymer

Multiple subunits bonded together.

Biological Macromolecule

A molecule containing a very large number of atoms which serves fundamental cellular functions of life.

Carbohydrate

An organic biological macromolecule containing carbon, hydrogen, and oxygen near a 1:2:1 ratio including sugars and starches.

Monosaccharide

One of three single subunits of carbohydrates (glucose, fructose, and galactose).

Disaccharide

Two monosaccharides bonded together.

Polysaccharide

Many monosaccharides bonded together.

Simple Sugar

A monosaccharide (glucose, fructose, or galactose).

Complex Sugar

A disaccharide or polysaccharide.

Lipid

An organic biological macromolecule containing carbon and hydrogen near a 1:2 ratio including fatty acids, glycerides, steroids, and phospholipids.

Fatty Acid

One monomer of lipids forming a long chain hydrocarbon.

Glyceride

A lipid polymer containing a glycerol and one, two, or three fatty acids used for lipid storage.

Steroid

A lipid with a four ring structure such as cholesterol and many hormones.

Phospholipid

A diglyceride with a single attached non-lipid group (i.e. phosphate) used to create cellular membranes.

Protein

An organic biological macromolecule comprised of amino acids.

Amino Acid

A series of 20 monomers of protein.

Peptide

Amino acids connected together by a peptide bond.

Dipeptide

Two amino acids held together by a peptide bond.

Polypeptide

Three or more amino acids held together by peptide bonds.

Substrate

A reactant in an enzymatic reaction.

Active Site

A region of an enzyme where a substrate can bind.

Nucleic Acid

An organic biological macromolecule containing many nucleotides which serves as information (i.e. DNA, RNA) or energy (i.e. ATP) storage.

Nucleotide

An organic biological monomer containing a sugar, phosphate, and nitrogenous base.

DNA

A pair of complementary nucleic acids bound together by hydrogen bonds in a double helix structure that stores information.

RNA

A single-stranded nucleic acid structure that stores and transfers information.

ATP

A high energy nucleotide used for energy storage and transfer; adenosine with three phosphates.

ADP

A high energy nucleotide used for energy storage and transfer; adenosine with two phosphates.