Gene mutations

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  • Created by: mutsa__
  • Created on: 23-01-17 11:42

Mutations:

  • A mutation is a random change to genetic material which can be either a change in gene or chromosome structure 
  • Individuals showing a caryying a mutation are known as mutants
  • Mutagenic are chemical/ physical agents causing a mutation 
  • Some of the features of mutation include:
    • Random/ spontaneous
    • Rare 
    • Increased by radiation/ chemicals such as UV light, X-rays and gamma rays 

Types of Mutations:

  • During the replication of the DNA molecule errors can occur which cause a mutation
  • If this error occurs during mitosis, this causes a somatic mutation which is not passed onto the offspringIf error occurs during meiosis, the mutation can be inherited by the offspring
    • This may be associated with development of cancerous tumours 
  • Gene mutations such as these can affect protein production and functions
    • Proteins may include :
      •  Antibodies 
      • Enzymes 
      • Plasmic membranes
      • Haemoglobin 
  • There are two types of DNA mutations
    • Point mutation- One base pair is substituted for another 
    • Indel mutation- one or more nucleotide inserted/ deleted from a length of DNA causing a shift in sequence called frameshift 

Point mutations:

  • Within the Point  mutations there are 3 different types:
    The genetic code consists of nucleotide base triplets within DNA and during transciption of gene, the code is copied mRNA as codons using complementry-base pairing 
    • Silent 
    • Missence
    • Nonsense
  • SILENT MUTATIONS
    • Change of one base triplet where

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