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Revision Summary for Biology 2: Genetics & Inheritance
You should know, understand and be able to explain facts about the following:
· That mitosis produces additional cells for growth, repair and replacement
and that before each cell divides the genetic information (DNA) that forms
the chromosomes is copied so that new cells have the same genes as the
· That most animal cells differentiate (become specialised) at an early stage
in the animal's life, but that most plant cells have the ability to
differentiate throughout the life of the plant.
· That stem cells are unspecialised cells that are found in human embryos and
in some adult tissues such as bone marrow, and that they have the potential
to differentiate into different types of specialised cells.
· To know that cells that divide to form gametes (sperm & eggs) do so by
meiosis and that these gametes have a single set of genetic information
(chromosomes), whereas body cells have two sets.
· That fertilisation of an egg by a sperm results in the formation of a cell
(zygote) with new pairs of chromosomes, so sexual reproduction gives rise to
· The work of Mendel and why it's importance was not recognised until after
· Why DNA fingerprinting is possible and how specific proteins are made.
· That characteristics are controlled by genes which have different forms
· That only one copy of a dominant allele (on one of the two chromosomes) is
needed for the characteristic to be shown/present in an organism; but that
recessive alleles must be present on both chromosomes for the
characteristic to develop.
· That in humans, the sex chromosomes determines whether you are female
(XX) or male (XY).
· To know that some human disorders are inherited, and may be the result of
the inheritance of a dominant allele (Huntington's disease), or require the
inheritance of two recessive alleles (cystic fibrosis).
· That embryos can be screened for genetic disorders.
You should be able to use your knowledge of how Science works to do the following:
· To explain why Mendel proposed the idea of separately inherited factors; and why the
importance of this discovery was not recognised until after his death.
· To make informed judgements about the social and ethical issues concerning the use of
stem cells from embryos in medical research and treatments, using both documents and
JB March 2008