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DNA, Genes and Chromosomes. The Nucleus. Control centre of the cell. Decides what kind of cell it will be, what functions it will perform and how long it will live for . The chemical that contains these instructions is DNA ( d eoxyribo n ucleic a cid). DNA.
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The Nucleus • Control centre of the cell. • Decides what kindof cell it will be,what functions it will perform and how long it will live for. • The chemical that contains these instructions is DNA (deoxyribonucleic acid).
DNA • The DNA molecule is very long and its basic structure is the same in every organism • (The structure was first discovered in 1953 looks like a twisted ladder)
Genes • A gene is a short section of the DNA molecule with a very specific code. • Examples: eye colour, height, hair colour…. • There are on average about 1000 genes on one DNA molecule!
Chromatin • DNA molecules folded and coiled into long threads • Without this folding/coiling each DNA molecule would be 2 metres long!
Chromosomes • Made of a single DNA molecule • Each kindof plant and animal has a specific number of chromosomes • Humans have 46 chromosomes
In humans, the mother gives23 chromosomes and the father 23 chromosomes to give46chromosomes to the new developing fetus • Every cell in you has 46 chromosomes • (except sperm and eggs – they only have 23!)