Section H: Human Inheritance (Terms (using hair colour as an example)…
Section H: Human Inheritance
(using hair colour as an example)
exist in alternative forms called
The ginger hair allele is
because it can be hidden by a brown hair allele. therefore somebody to have ginger hair, they must have two copies of the ginger hair allele.
e.g. the gene is for hair colour two alleles; one for brown one for ginger.
The brown hair allele is
because it determines the characteristics even if only one copy is present.
made, it will only contain one of the alleles
is the appearance / measurable characteristics (e.g. hair colour)
is when both the alleles are the same
: The alleles each cell has for a certain feature
is when the two alleles are different
body is made up of cells. each cell contains a
which controls the cell
Each nucleus contains lots of thin threads called
carry information which controls how your body works and what you look like
Each chromosome is made up of tangled threads. each thread is made up of a very long molecule called
is a length of DNA.
each gene gives instructions for a different characteristic e.g. eye colour
A cross between two parents who possess different forms (alleles) of a gene is called monohybrid inheritance.
numbers of chromosomes
46 is the diploid number chromosomes in a human cell
23 is the haploid number of chromosomes in a human
Structure of DNA
a DNA molecule
coiled together in the shape of a
The two strands are held together by chemicals called
. There are
The bases are
and they always pair up in the same way - its always A-T and C-G. this is called
DNA is a type of
the sex of a person is determined by one pair of Chromosomes - XX for female and XY for males