Inside the nucleus are chromosomes
Chromosome = 1000s of coils of genes
Genes = comprise ‘DNA’ that decides our characteristics
DNA = deoxyribose nucleic acid (chemical)
Each gene acts as a code for a particular characteristic
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A human egg cell and sperm cell contains 23 chromosomes
Embryo therefore contains 23 pairs of chromosomes
Each pair contains a gene from your mother, and a gene from your father for a particular characteristic
So each pair contains two “options” for a characteristic
These options are called alleles e.g. gene = eye colour; alleles = blue eye colour, brown eye colour
DNA and the Human Genome Project
A brief introduction to DNA with a computer graphic of the double helix stricture. The Human Genome Project is explained and screening for genetic diseases such as sickle cell anaemia and thalassemia is discussed. Detail is given regarding the genetic basis of these diseases. The concept of designer babies is also introduced.
