20.1 Gene Mutations

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What are the the 3 consequences of substitution of bases?
the formation of one of the stop codons, formation of a codon for a different amino acid and the formation of a different codon that codes for the same amino acid.
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What does the deletion of bases cause?
a frame shift to the left
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What is the consequence of the deletion of bases?
the gene is read in the wrong 3 base groups and the coded information is altered. the polypeptides will be different and lead to the production of a non-functional protein, that could alter the phenotype considerably.
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What is the addition of bases?
an extra base becomes inserted in the sequence.
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What is the consequence of the addition of bases?
there is a frame shift to the right. if 3 extra bases are added, or any multiple of 3 then there is no frame shift. the resulting polypeptide will be different from the one produced but not to the same extent as if there was a frame shift.
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What is the duplication of bases?
one or more bases are repeated, resulting in a frame shift to the right.
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What is the inversion of bases and the consequence?
a group of bases become separated from the DNA sequence and rejoin at the same position but in the inverse order. the base sequence of this portion is therefore reversed and effects the amino acid as a result.
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What is the translocation of bases?
a group of bases become separated from the DNA sequence on one chromosome and become inserted into the DNA sequence of a different chromosome.
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What is the consequence of translocation of bases?
translocation often has significant effects on gene expression leading to an abnormal phenotype. effects include he development of certain forms of cancer and also reduced fertility.
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What are the 2 mutagenic agents?
high energy ionising radiation and chemicals
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Card 2

Front

What does the deletion of bases cause?

Back

a frame shift to the left

Card 3

Front

What is the consequence of the deletion of bases?

Back

Preview of the front of card 3

Card 4

Front

What is the addition of bases?

Back

Preview of the front of card 4

Card 5

Front

What is the consequence of the addition of bases?

Back

Preview of the front of card 5
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