The Nucleic Acids or Nucleotides (DNA Monomers)

DNA is a large molecule composed of multiple nucleotides pared together. In this arrangement a purine will associate with a pyrmidine to form a "Base Pair". Adenosine will pair with Thymidine (A-T) and Cytosine with Guanine (C-T).


PYRMIDINE BASES	PURINE BASES

Protein Folding and Function

The shape of proteins is what determines how it functions. With an incorrect base, in some cases it is the folding that is distorted. As such the protein loses its functionality. Radiation affects this arrangement by altering the chemical structure of a base and switching it to it alternate structure (i.e. Cytosine to Thymidine etc.) This disrupts the bases pairing leading to faulty proteins that are incorrectly folded. If these proteins are pare of the cell cycle control (ras or p53) often these cells can become cancerous as the replication machinery of the cell runs out of control.

ras- inhibits cell growth - a misfolded ras will not perform its function leading to uncontrolled cell replication

Even one base pair change can lead to disastrous effects - the change in the "Active site" can render the protein / enzyme useless.

Sickle Cell Anemia results for a single base pair change in the oxygen carrying hemoglobin (in blood). As such it changes the structure of the red blood cell so it cannot flow through the body properly and cannot carry oxygen very well.