recall that the nucleus of a cell contains chromosomes on which genes are located.
-chromosomes are genetic information within a cell.
-typical cell will have a nucleus, and if you open the nucleus up you will find a number of chromosomes.
-a chromosome is composed of a molecule called DNA (DeoxyriboNucleic Acid), this forms a shape known as the double helix.
-sections of the molecules are called genes
-one chromosome will have many genes possibly thousands of genes.
-each gene carries the information for the construction of a protein.
-protein gives us the characteristics associated with the genes eg. blood group.
-different organisms have different numbers of chromosomes.
- cat- 38 chromosomes.
- chicken- 78 chromosomes
- chimpanzees- 42 chromosomes.
- human- 46 chromosomes
-the homologous nature is based on the length of the chromosomes.
-the 2 arrows on the diagram above is the gene loci. if you go to the same position on the homologous pair you find the same gene (gene loci)
-there is 2 versions of each gene for one characteristic. (alleles)
question- is the number of chromosomes in human males and females the same?
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