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Advanced Biology

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Advanced Biology Mutations – PowerPoint PPT presentation

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Title: Advanced Biology


1
Advanced Biology
  • Mutations

2
  • What is a mutation?
  • A change (mistake) in the replication of genetic
    material.
  • The daughter cell is different from the parent

3
  • Most replication errors are corrected by the
    cells built in spell check system.
  • However, some do escape detection

4
Gene Mutation
  • Deletion Leaving out one nucleotide in the
    sequence, shifts the reading of the sequence to
    the left, creating a totally different set of
    amino acids

5
Gene Mutation
  • Normal mRNA reads
  • AUG AAG UUU GGC GCA UUG UAA
  • Met Lys Phe Gly Ala Leu Stop.
  • Mutated mRNA reads
  • AUG AAG UUG GCG CAU UGU AA
  • Met Lys Leu Ala His Cys

6
Gene Mutation
  • Insertion Mutation in which an extra nucleotide
    is added to the chain during replication, shifts
    reading to the right, creating a totally
    different set of amino acids

7
Gene Mutation
  • Normal mRNA reads
  • AUG AAG UUU GGC GCA UUG UAA
  • Met Lys Phe Gly Ala Leu Stop.
  • Mutated mRNA reads
  • AUG AAG UUU GUG CGC AUU GUA A
  • Met Lys Phe Val Arg Ile Val

8
Gene Mutation
  • Point Mutation A base substitution occurs. One
    nucleotide is replaced with a different one

9
Gene Mutation
  • Normal mRNA reads
  • AUG AAG UUU GGC GCA UUG UAA
  • Met Lys Phe Gly Ala Leu Stop.
  • Mutated mRNA reads
  • AUG AAG UUU AGC GCA UUG UAA
  • Met Lys Phe Ser Ala Leu Stop.

10
Gene Mutation
  • These mutations arise spontaneously during DNA
    replication.
  • External agents may cause mutations, called
    mutagens.

11
Chromosome Mutations
  • Changes may occur in chromosomes as well as in
    genes.
  • Chromosome mutations can have serious effects on
    the distribution of genes to gametes during
    meiosis.

12
Chromosome Mutations
  • Deletion
  • ABCDE---FGH
  • ABCE---FGH

13
Chromosome Mutations
  • Duplication
  • ABCDE---FGH
  • ABCBCDE---FGH

14
Chromosome Mutations
  • Inversion
  • ABCDE---FGH
  • ADCBE---FGH

15
Chromosome Mutations
  • Attachment to a different chromosome
  • ABCDE---FGH
  • WXY---Z
  • WXABCDE---FGH
  • Y---Z

16
Other causes of genetic variation
  • During meiosis, homologous pairs fail to
    separate.
  • This would cause the offspring to have an extra
    chromosome.

17
CANCER
  • Abnormal cells, go through cell cycle very fast,
    creating new cells like it.
  • They reproduce in an uncontrolled way, crowding
    out healthy cells and destroying tissues and
    possibly organs.
  • It can spread to other parts of the body

18
Causes of Cancer
  • Genes that control the cell cycle mutate, called
    an oncogene.
  • Mutations may be inherited or caused by a
    carcinogen, a cancer causing agent in the
    environment.
  • Tobacco smoke, radiation and other chemicals.

19
Causes of Cancer
  • Viruses may also cause cancer.
  • Their presence disrupts normal cell processes.
  • They can also carry oncogenes into the host cell.

20
Technology
  • Scientists can transfer a gene artificially from
    a donor organism to a bacteria.
  • The DNA of the bacterium is called recombinant
    DNA.
  • The bacteria will transcribe and translate the
    foreign gene and produce the protein it is coding
    for.

21
Technology
  • Small, circular pieces of DNA, called plasmids,
    are where the foreign DNA is placed.

22
Technology
  • To obtain a foreign gene, mRNA from a cell is
    isolated and DNA is produced (called reverse
    transcription). This single stranded DNA is
    converted to a double strand and this double
    strand is the desired gene.

23
Technology
  • In use today goats that produce a human blood
    clot dissolving factor.
  • Plants that are disease resistant.
  • Plants that are larger than normal.
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