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Genetic Make-Up
http://www.accessexcellence.org/AB/GG/chromosome.html
CELLS:
Sex Cells have 1/2 the chromosomes that other body cells have.
Meiosis - The process by with the # of Chromosomes is reduced by 1/2 to form egg and sperm cells. Meiosis animation.
Chromosomes:
Composed of DNA
Humans have 23 Pair of chromosomes which contain more than 60,000 genes.
Genes are lined up in the same order from one end of the chromosome to the other. Each Chromosome has the same genes but the alleles for some genes may be different. Genes, Alleles, Traits...What's the difference?
http://www.accessexcellence.org/AB/GG/genes.html
DNA:
DNA - Deoxyribonucleic acid
Made up of Nitrogen Bases (colored rungs in picture).
www.tela.co.uk/cellcity/ nucleus.htm
Nitrogen Bases:
DNA is made up of 4 different Nitrogen Bases. Adenine, Thymine, Guanine and Cytosine.
A single gene may contain anywhere from several hundred to a million or more bases and each gene controls a specific trait.
The order of the Nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced.
Proteins help determine, the size, shape and traits of an organism.
