When a cell divides, we can see small, stick-like objects called chromosomes which are made up of a coiled thread-like substance called Chromatin. When the chromatin is uncoiled, the DNA molecule is revealed. It is formed of nitrogenous bases linked in chains. The sequence in which the ladder is linked amounts to the code which determines the characteristics of an individual. These are called genes and makes each of us unique.

Originally released by QA International, 2005. Streaming video file encoded with permission for digital streaming by Infobase on May 06, 2015.

Chromosomes and DNA (1:00); .