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The Structure of DNA.           

DNA causes the variety of life.

-       Found in the nucleus

-       Humans have 23 pairs of chromosomes.

-       Reproduction cells (gametes) only have 23 chromosomes.

-       In chromosomes there are genes

-       Genes are a length of DNA that codes for a protein.

-       These determine everything about you.

-       Genes have different alleles (hair is black, or blue of brown)

-       DNA controls all the chemical changes in the cell

-       DNA is a very large molecule made of long chains of subunits.

-       DNA is a polymer- made of lots of subunits called nucleotides.

Nucleotides consist of deoxyribose sugar, a phosphate group and a base.

The phosphate group contains phosphorous and oxygen.

This is an example of a pentose sugar- it has 5 sugars.

The base contains Nitrogen.

There are 4 possible bases

1)   Adenine

2)   Thymine

3)   Guanine

4)   Cytosine

A molecule of DNA is formed by millions of nucleotides joined together in a long chain.

The nucleotides join together in a condensation reaction; meaning H2O is released. DNA molecules consist of 2 strands of DNA. These strands join together to form a…


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