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C9 Life on Earth
Mutations…read more

Slide 2

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C9 Mutations
How is variation produced?…read more

Slide 3

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C9 Mutations
Natural selection in rats: warfarin
These statements describe how the
number of warfarin resistant rats may
increase in a population.
Warfarin kills most rats.
But a few are resistant to the poison.
People use warfarin to kill the rats. But there is a big
The resistant rats survive the poison.
unanswered question:
The resistant rats breed.
They pass on their features to the next
How do some rats
become resistant to
The number of resistant rats increases warfarin in the first
with each generation. place?…read more

Slide 4

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C9 Mutations
How do some rats become resistant to warfarin?
Click on the links to find out more.
DNA is a genetic code. The code is made up of chemicals called bases.
The order of the bases controls the proteins that a cell makes.
Remind me about DNA.
When a cell divides its DNA has to be copied for the new cell.
Sometimes a mistake is made when the DNA is copied.
The order of the bases is changed - this is a mutation.
Tell me more about mutations.
Most mutations are harmless, some are harmful. Very rarely
mutations may be helpful to an organism.
What sort of mutations can be helpful?…read more

Slide 5

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C9 Mutations
DNA molecules are very long.
They have a double helix shape. chromosome
Each DNA molecule is made up of
smaller molecules called bases.
Chromosomes are made of DNA.
Genes are sections of chromosomes.
The order of DNA bases in a gene is
an instruction for a cell.
It is the instruction for how to part of DNA
make one type of protein.…read more

Slide 6

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C9 Mutations
The order of the bases in a gene is
the genetic code.
Each gene is an instruction for making
one type of protein.
Proteins are made of amino acids
joined together.
The genetic code controls the order
that amino acids are joined up in.
If the order of bases is changed, the
cell may put a different amino acid in
the protein.
This changes the shape of the protein.
The protein may work differently in
the cell.…read more

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