3.16

+ A chromosome contains thousands of genes
+ Looking at 1 gene loci you can magnify it to see a double helix - they apear parallel
+ Expanding more you can see the 2 sugar phosphate back bone sides and in between holding them together are the bases.
+ There are 4 types of bases:  Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
+ They are always found in DNA in pairs    T-A      G-C
+ On one side the order of them is ACTGAACCAG "order of bases" this is the order we call a gene
+ The gene is found in the nucleus of a cell: order of the bases and number of the bases = protein in cytoplasm -> characteristic.