5.5 When genes change

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

5. It runs in the family

On inheritance, family trees, genetics and DNA

5.5 when genes change

    What is a mutation?

    How can a disease be inherited from one generation to the   

    next?

mutations

= change in a gene or chromosome (genotype)

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

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

mutations 

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
  

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

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'

Genetic counselor

role play

Project starts in two weeks

You''l become a genetic counselor. A couple with a child's wish will visit you. You have to advice them on the probabilities of having a baby with a genetic disease

 

Read section 5.5

Do exercises 30, 31, 32 (34, 35 and 36)