Page 29 - CB1.3 Genetic Varation sciPAD

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CB 1.3 GENETIC VARATION
PRINCIPLES OF GENETIC VARIATION
Hints for answering
these questions
5. Genes determine many of the features of organisms, such
as the colour of the fur on rats.
A gene is a part of a DNA molecule.
The type of rat shown on the right can have black or white
fur.
Discuss how information in DNA gives organisms (like the
rat) their individual features, such as black and white fur.
In your answer, you should:
•
explain the difference between a ‘gene’ and an ‘allele’.
•
explain how the base sequence on DNA determines a particular feature (e.g.
fur colour) and different forms (variations) of that feature (e.g. black and white
fur).

































Explain the
difference between
a gene and an
allele in terms of
how they impact on
traits.
Describe how a
gene codes for a
protein, which then
determines a trait.
Explain that the
base sequence on
a gene determines
the appearance of
a particular feature
(in this case the rat’s
fur colour).
You might like to
show the relationship
between a gene
and an allele in
a diagram of a
chromosome.
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