9.1- Gene mutation

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  • Created by: Megan2413
  • Created on: 13-06-17 16:56
What is a mutation?
Any change to the quantity or the base sequence of the DNA of an organism
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What is a gene mutation?
Any change to one or more nucleotide bases, or a change in the sequence of the bases
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What is a chromosome mutation?
Changes in the structure of number of whole chromosomes
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What are the two types of gene mutation?
- Substitution - Deletion
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What occurs during a substitution mutation?
When a base is substituted for another base, for instance AUG UUG ACA --> AUG UAG ACA, the fifth base was changed from U -> A
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What overall effect may a substitution mutation have on the polypeptide coded for?
It may change a single amino acid produced, or due to the genetic code being degenerate it may not change the amino acid being produced at all
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What is a deletion mutation?
When a base is removed completely from the base sequence for example UAC CCG UUC --> UAC CCG UCA, the eigth base was removed completely from the first code
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What effect may a deletion mutation have on the polypeptide being produced?
It may change several amino acids being coded for as when a base is removed, it will shift the whole base sequence one base along, changing all the following base triplets. This will change the primary sequence, so the protein structure and function
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What are the two types of chromosome mutations?
- Polyploidy - Non-disjuntion
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What is polyploidy?
When organisms have three or more sets of chromosomes than the usual two. It occurs in most plants
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What is non-disjunction?
The process by which homologous pairs of chromosomes fail to separate during meiosis, which usually results in a gamete having one more or fewer chromosomes
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What is an example of non-disjunction in humans?
Humans with down's syndrome have an additional chromosome 21
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Card 2

Front

What is a gene mutation?

Back

Any change to one or more nucleotide bases, or a change in the sequence of the bases

Card 3

Front

What is a chromosome mutation?

Back

Preview of the front of card 3

Card 4

Front

What are the two types of gene mutation?

Back

Preview of the front of card 4

Card 5

Front

What occurs during a substitution mutation?

Back

Preview of the front of card 5
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