Structure of DNA
DNA holds all the genetic information in living organisms. DNA is coiled into
structures called chromosomes, which are then stored in the nucleus of
Chromosomes exist in pairs, humans contain 23 pairs of chromosomes and
half of those pairs come from each parent. Therefore in human gametes,
sperm cell and egg cell, they only contain 23 chromosomes.
A gene is a portion of DNA that controls a certain characteristics.
e.g. eye color