3.14

 chromosomes are the genetic information within a cell they are found in the nucleus. 

DNA

in the structure of a double helix 

in 1 chromosome there are 1000's of genes   ----> each gene carries the information for the construction of a protein-----> the protein gives us the characteristic associated with a gene e.g blood group 

 2: different orgainisms have a different number of chromosomes per cell e.g cat = 38
                                                                                                     chicken = 78
                                                                                              chimpanzee = 42
                                                                                                    humans = 46




chromosomes are known to operate in pairs known as homologous pairs.

homologous nature is based on the length of the chromosomes.

---> gene loci here   <--- will be the same as the                    

                                                                                                                                 gene loci on this side

2 versions of each gene for 1 characteristic. 

 ^

called alleles