DNA – double stranded molecule located only in the nucleus of a cell that transmits the genetic material from 1 generation to another and directs all cellular activity

RNA – single stranded molecule that can be anywhere in the cell that is responsible for protein synthesis and for the direction of enzymes

Phosphate and sugar – form the backbone of the DNA molecule

Nitrogenous bases – form the ladder of the DNA molecule. The purines (adenine and guanine) and pyrimidines (thymine, cytosine) that comprise DNA and RNA molecules.

Purines – adenine(A) and guanine(G)

Pyrimidines – cytosine(C) and thymine(T)

Nucleotide - A subunit of DNA or RNA consisting of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a  sugar molecule (deoxyribose in DNA and ribose in RNA). Thousands of  nucleotides are linked to form a DNA or RNA molecule.

Gene – a segment of DNA found on a chromosome that codes for a particular protein

DNA replication - The process of making an identical copy of a section of (double-stranded) DNA, using existing DNA as a template for the synthesis of new DNA strands. Replication occurs in the cell nucleus.

DNA polymerase – any of the several polymerases that promote replication or repair of DNA usually using single-stranded DNA as a template.

G1 Phase (gap 1) – where the cell spends most of its normal life

G0 Phase – where cells that are temporarily non-cycling go after they leave G1 Phase

S Phase (synthesis) – synthesis of DNA takes place in this phase. (most radioresistant phase)

G2 Phase (Gap 2) – cell takes an inventory of itself with checkpoint genes

Checkpoint genes – examines DNA content and reverses damage or corrects DNA

Mitosis (M Phase) – cell division takes place in which the nucleus divides into nuclei containing the same number of chromosomes(most radiosensitive phase)