With thanks to Jenny P
DNA is a very long molecule that looks like a twisted ladder.
It is made up of 4 different subunits called nucleotides which can be arranged in any order
The bases are complementary
DNA has two strands.
The strands are stuck together by the complementary bases.
Adenine to Thymine A-T
Cytosine to Guanine C-G
It is the Sequence of bases that act like a code
The sequence (order) of bases tells the cell what proteins to make.
The sequence of bases dictates the sequence of amino acids, which determines the shape of a protein.
If the protein is the wrong shape it will not work properly (it may work differently)
So if the sequence in the DNA is wrong it may result in a genetic disease
Sickle cell anaemia is caused by one change in the DNA base code
It is a triplet code.
It takes 3 bases to code for one amino acid
Each triplet codes for a different amino acid.
DNA carries the code for every protein that can be made by a cell.
A gene is a length of DNA which codes for a particular protein
Protein Synthesis takes place in 2 stages
Part of the DNA molecule (the gene) unzips
An RNA copy is produced, by matching complementary bases
The mRNA copy is made with the help of RNA polymerase.
The m-RNA leaves the nucleus through a nuclear pore
RNA leaving the nucleus