Gene Mutations

  • Created by: Esme.B
  • Created on: 09-01-18 13:56
a change in the sequence of the nucleotide bases of DNA
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Two types of mutation?
Point mutation + Insertion/ deletion
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Point mutation?
One base pair replaces (is substituted for) another.
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3 types of point mutation?
Silent + Missense + nonsense
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Silent mutation?
Change in base triplet but still codes for the sam amino acid
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Missense mutation?
Change in base triplet but changes the animo acid sequence - sickle cell anaemia
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Nonsense mutation?
Nonsense is known as a Stop codon means the protein won’t be fully built and won’t function properly- Duchenne muscular Dystrophy
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Insertion or deletion mutation?
Nucleotides are inserted or deleted from length of DNA, this causes a frameshift
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Framing error occurs due to insertions or deletions. - always causes large changes.means that the polypeptide produced is useless or has a stop code half way through.
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Example of an Insertion mutation?
Huntington's disease
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Example of a deletion mutation?
Cystic fibrosis
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List 2 mutations which are un-harmful?
1). Differently shaped ear lobes. 2). Inability to smell certain flowers i.e honeysuckle
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Chromosome Mutation?
mutation may cause a change Chromosome Mutation = in the structure or number of whole chromosomes in cells.
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Environmental Factorssignificantly increase the chance of a mutation occuring.
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List 3 examples of Environmental factors?
X­rays and gamma rays, Ultra Violet Radiation + smoking
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List 3 features , that makes DNA structure stable and fairly resistant to mutations ?
Covalent bonds between nucleotides,Found in nucleus,Hydrogen bonds between base pairs + double Helix
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Explain how the degenerate nature of the genetic code reduces the effects of point mutations.
In some cases a change to the triplet code does not change the amino acid coded for at that point in the polypeptide chain.
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Sometimes during translation, a tRNA molecule may combine with the wrong amino acid. How may this affect the protein being assembled at a ribosome?
An incorrect amino acid would be inserted into the polypeptide chain, even though there is no point mutation in the DNA/gene.
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Other cards in this set

Card 2


Two types of mutation?


Point mutation + Insertion/ deletion

Card 3


Point mutation?


Preview of the front of card 3

Card 4


3 types of point mutation?


Preview of the front of card 4

Card 5


Silent mutation?


Preview of the front of card 5
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