5.5 When genes change

5. It runs in the family
On inheritance, family trees, genetics and DNA

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BiologieMiddelbare schoolvwoLeerjaar 3

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5. It runs in the family
On inheritance, family trees, genetics and DNA

Slide 1 - Diapositive

Draw a Punnett square showing the crossing of the F1 flowers from Mendel's pea plants.

Slide 2 - Question ouverte

purple x white gives purple offspring. Purple must be dominant
    P = purple
    p = white
Purple F1 crossing gives purple + white flowers
F1 must be Pp

Slide 3 - Diapositive

F1: Pp x Pp

F2: PP 25% Purple
      Pp 50% Purple
      pp 25% White
P
p
P
PP
Pp
p
Pp
pp

Slide 4 - Diapositive

5.5 when genes change
    What is a mutation?
    How can a disease be inherited from one generation to the   
    next?

Slide 5 - Diapositive

Slide 6 - Vidéo

mutations
= change in a gene or chromosome (genotype)

This may result in no/small/large change in phenotype

Slide 7 - Diapositive

mutations
= change in a gene or chromosome (genotype)

This may result in no/small/large change in phenotype

the change can be negative/neutral/beneficial

Slide 8 - Diapositive

mutations 

Slide 9 - Diapositive

mutations 
External caused by known mutagens 
  • Radiation: (eg. UV light, X-ray, radioactive decay)
  • Chemicals (eg. benzene in cigarette smoke)
  • Bacteria or viruses (eg. HPV)
Internal
  • DNA replication




Slide 10 - Diapositive

mutations 
Gene mutations
    Defect of a gene
    eg. sickle cell disease
Chromosome mutations
    Change in a whole chromosome
     eg. extra chromosome 21 leads to Down Syndrome


Slide 11 - Diapositive

Definitions
A= healthy
a = sickle cell disease

Person with AA is healthy
Person with aa has sickle cell disease
Person with Aa is a 'carrier'

Slide 12 - Diapositive

Read section 5.5
make the assignments

Slide 13 - Diapositive