Contents
Key Stage 3
Meaning
DNA is the molecule inside an organism that provides instructions on how to build that organism and how the cells behave inside the organism.
About DNA
- DNA is found in the nucleus.
- DNA coils together to make chromosomes.
- DNA is passed from parent to offspring.
- DNA controls most of our physical appearance.
- DNA determines your eye colour, nose shape, height, skin colour and whether you are male or female. All of these things can be affected by environment as well, but the DNA provides the original instructions on how to build you.
- DNA has a double helix structure, which means it is shaped like twisted ladder.
Discovery of DNA
- DNA was first discovered in 1869, but at the time nobody knew how it worked or what its structure was.
- In 1928 an experiment with DNA showed that it was responsible for heredity.
- In 1953 Francis Crick and James Watson found evidence that DNA was a long double helix molecule.
Key Stage 4
Meaning
DNA is a polymer made of nucleotides which provides instructions for the structure and behaviour of an organism.
About DNA
- DNA stands for deoxyribose nucleic acid.
- DNA is found in the nucleus of eukaryotes and floating freely in the cytoplasm of prokaryotes.
- DNA in eukaryotes coils together to make chromosomes.
- DNA is arranged in genes that control most of our physical appearance.
- DNA has a double helix structure, which means it is shaped like twisted ladder.
- DNA is made from four nucleotide bases called Adenine, Thymine, Cytosine, and Guanine referred to as A, T, C and G.
- The nucleotides are arranged in complementary pairs. Adenine and Thymine pair up on opposite sides of the DNA strand. The same is true for Cytosine and Guanine. When the strand is pulled into two pieces this allows the DNA to make two exact copies of itself.