Download B1 You and Your Genes

B1 You and Your Genes
Science Explanations (bold type signifies Higher only)
You should know:
 Most of your features are affected by your environment and your genes
 Genes are found in the nuclei of cells and are instructions for making proteins
which may be structured or enzymes
 Your chromosomes, and genes, are in pairs
 Genes have different versions, called alleles
 The difference between dominant and recessive alleles
 Men and women have different sex chromosomes (men XY, women XX)
 How a gene on the Y chromosome causes an embryo to develop as a man
 Why you look like your parents
 Why you may look like your brothers and sisters, but not be identical
 How to interpret family trees
 How to complete genetic cross diagrams
 The symptoms of cystic fibrosis and Huntington’s disorder
 Why people can be carriers of cystic fibrosis, but not Huntington’s disorder
 Doctors can test embryos, foetuses and adults for certain alleles by genetic
tests
 What happens during embryo selection (pre-implantation genetic diagnosis)
 The implications of the use of genetic testing by others (e.g. by employers
and insurance companies) and comparisons of technical feasibility against
values
 How gene therapy could be used to treat some genetic disorders
 That some organisms use asexual reproduction and have offspring that are
clones
 How animal clones are produced naturally and artificially (when the nucleus
of an adult cell is transferred to an empty fertilised cell)
 That cells in multi-cellular organisms become specialised very early on in
organism’s development
 What stem cells are, and how they could be used to treat certain diseases