Powerpint mutation
Upcoming SlideShare
Loading in...5
×
 

Powerpint mutation

on

  • 1,769 views

Source:http://www.biology-resources.com

Source:http://www.biology-resources.com

Statistics

Views

Total Views
1,769
Slideshare-icon Views on SlideShare
1,195
Embed Views
574

Actions

Likes
0
Downloads
26
Comments
0

1 Embed 574

http://mravagnan.cumbresblogs.com 574

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Powerpint mutation Powerpint mutation Presentation Transcript

    • SOURCE OF VARIATION: MUTATION
      Is a change in a gene orchromosome
    • 14
      Mutations
      A mutation is a spontaneous change in a gene or
      chromosome
      • Gene mutations may arise when a gene fails to make an exact
      copy of itself during replication prior to meiosis or mitosis
      • Chromosome mutations can result from:
      -Damage to, or loss of a chromosome
      -Incomplete separation of chromosomes at meiosis leading to
      extra chromosomes in one gamete
      -Part of a chromosome becoming attached to another chromosome
      (translocation)
      - Doubling the whole set of chromosomes
    • 22
      Chromosome mutations in humans usually result in spontaneous
      abortion of the foetus
      But a proportion survive e.g.
      Downs syndrome: The affected person has one extra chromosome
      in their genome (i.e. 47 instead of 46 chromosomes)
      This results in characteristic facial features, varying degrees of
      mental impairment and, usually, a very cheerful disposition
      Klinefelters syndrome. The affected male has an extra
      X chromosome (XXY)
      The person appears to be a normal male but he is infertile
      Chromosome mutations in humans
    • 25
      -A mutated gene which is dominant, or inherited as a homozygous
      recessive, will affect the whole organism
      -A mutated gene which does not result in abortion or early death
      of an organism will be inherited by the offspring
      -Very rarely, a mutation will be beneficial and will be inherited by
      the offspring
      Gene mutations in humans may result in:
      Albinism
      Sickle cell anaemia
      Haemophilia
      Cystic fibrosis
      Dwarfism
      Colour blindness
      Mutations
    • 26
      -If a gene mutation takes place in a gamete which contributes to
      a zygote, the mutation will affect the whole organism
      -A gene mutation in a body cell will affect only that cell and
      any cells derived from it.
      • It is mutations in body cells which give rise to cancers.
      -These mutations usually affect the genes which control cell division
      -The control on cell division is reduced so that the cell divides
      repeatedly, giving rise to a tumour
    • 30
      Mutagens
      Some environmental effects may increase the mutation rate.
      These include radiation (X-rays, ultra-violet, radioactive materials) and carcinogenic chemicals such as those in tobacco smoke
      These are all known as mutagens
      -Mutagens which affect body cells may produce cancers.
      -Mutagens affecting the reproductive organs may result in defective offspring
    • Question 1
      35
      Chromosome mutations can occur as a result of…
      (a) gain of an extra chromosome
      (b) doubling of the entire set of chromosomes
      (c) faulty replication of DNA
      (d) breaking of a chromosome
    • 36
      Question 2
      Gene mutations can occur during DNA replication
      prior to …
      mitosis
      (b) meiosis
    • Question 3
      37
      Sickle cell anaemia results from …
      a change in a nucleotide triplet
      (b) a change in a single nucleotide
      (c) a change in a single amino acid
      (d) a chromosome mutation