The Chemistry of Life - BIOL 170 Lecture 3

Key vocabulary terms from Lecture 3 of BIOL 170 on the Chemistry of Life.

Cell

The fundamental unit of life; multicellular organisms consist of many cells while unicellular organisms consist of one cell.

Organelle

A membrane-bounded structure within a cell that has a specific function, e.g., chloroplast.

Molecule

A group of joined atoms, e.g., DNA.

Atom

The smallest chemical unit of a pure substance (element), e.g., carbon atom.

Bulk Element

Elements that are most abundant in living organisms, such as carbon, hydrogen, oxygen, and nitrogen.

Trace Elements

Elements that are required by living organisms in minute amounts, e.g., iron, iodine.

Ion

An atom that has lost or gained electrons and has a charge, e.g., Na+ or Cl-.

Isotope

Different forms of the same element that have the same number of protons but different numbers of neutrons, e.g., Carbon-12, Carbon-13.

Covalent Bond

A chemical bond where atoms share electrons to achieve full outer electron shells.

Ionic Bond

A type of chemical bond formed through the electrostatic attraction between oppositely charged ions.

Hydrogen Bond

A weak bond that occurs when a hydrogen atom covalently bonded to an electronegative atom is attracted to another electronegative atom.

pH Scale

A measure of the acidity or basicity of a solution, ranging from 0 to 14.

Hydrophilic

Substances that have an affinity for water; they dissolve in water.

Hydrophobic

Substances that do not have an affinity for water; they do not dissolve in water.

Solvent

A substance that dissolves a solute, e.g., water.

Solution

A homogeneous mixture of two or more substances, e.g., salt water.

Biochemical

Compounds composed of atoms of different elements that are essential for life.