Homeostasis

The maintenance of a relatiely constants internal environment. 

Energy 

The ability to do work. Living organisms obtain energy from food, which they either make using the energy of sunlight or consume from the environment. 

Metabolism

All the chemical reactions taking place in the cells of a living organism that allow it to obtain and use energy. 

Element

A chemically pure substance that cannot be chemically broken down; each element is made up of and defined by a single type of atom. 

Atom

The smallest unit of an element that cannt be chemically broken down into smaller units. 

Proton

A positively charged subatomic particle found in the nucleus of an atom. 

Electron

A negatively charged subatomic particle with negligible mass. 

Neutron 

An electrically uncharged subatomic particle found in the nucleus of an atom. 

Nucleus

The dense core of an atom. 

Covalent Bond

A strong chemical bond reulting from the shring of a pair of electrons between two atoms. 

Molecule

Atoms linked by covalent bonds

Organic Molecule

A molecule with a carbon-based backbone and at least one C-H bond.

Inorganic Molecule

A molecule that lacks a carbon-based backbone and C-H bonds.

Carbohydrate

An organic molecule made up of one or more sugars. A one-sugar carbohydrate is called a monosaccharide; a carbohydrate with multiple linked sugars is called a polysaccharide. 

Protein

An organic molecule made up of linked amino acid subunits

Lipids

Organic molecules that generally repel water. 

Nucleic Acids

Organic molecules made up of linked nucleotide subunits; DNA and RNA are examples of nucleic acids. 

Macromoleules

Large organic molecules that make up living organisms; they include carbohydrates, proteins, and nucleic acids. 

Monomer

One chemical subunit of a polymer.

Polymer

A molecule made up of individual subunits, called monomers, linked together in a chain.

Monosaccharide

The building block, or monomer, of a caarbohydrate. 

Amino Acid

The building block, or monomer, of a protein. 

Nucleotide

The building block, or monomer, of a nucleic acid.

Cell

The basic structural unit of living organisms.

Phospholipid

A type of lipid that forms the cell membrane.

Phospholipid Bilayer

A double layer of lipid molecules that characterizes all biological membranes. 

Hydrophobic

"Water-Fearing"

hydrophic molecules will not dissolve in water. 

Hydrophilic

"Water-Loving"
hydrophilic molecules dissolve in water. 

Solvent

A substane in which other substances can dissolve; for example water. 

Solute

A dissolved substance

Solution

A mixture of slutes dissolved in a solvent

Polar Molecule

A molecule in which electrons are not shared equally between atoms, causeing a partial negative charge at one end and a partial positive charge at the otherp; for example water

Ionic Bond

A strong electrial attraction between oppositely charged ions. 

Ion

An eletrically charged atom, the charge reulting from the loss or gain of electrons.

Hydrogen Bond

A weak electrial attraction between a partially positive hydrogen atom and another atom with a partial negative charge. 

pH

A measure of the concentration of H⁺ in a solution

Acid

A substance that increases the hydrogen ion concentration of solutions, making them more acidic. 

Base

A substance that reduces the hydrogen ion concentration of solutions, making them more basic.

Virus

An infectious agent made up of a protein shell that encloses genetic information.

Prion

A protein-only infectious agent.