3.14 Chromosomes

recall that the nucleus of a cell contains chromosomes on which genes are located.

Chromosomes are composed of smaller molecules called DNA which forms the shape of a double helix.

each section of the DNA is called a gene

a single chromosome may contain thousands of genes

these genes hold the information used to produce protein

proteins give us the characteristic associated with the gene, such as blood group

different organisms have different number of chromosomes
Cat= 38
Chicken = 78
Chimpanzee = 42
Human = 46

chromosomes operate in pairs known as homologous pairs.
the nature of each pair depends on the length of the chromosome
the position of a gene is called the gene loci
if we go to the same position on the other chromosome in the same homologous, we will find another version of the same gene.