5.5 When Genes Change

• Biologie
• 9th Grade

Today

1. Quiz
2. HW check: 30 - 32 + 34
3. Continue: 5.5

Which autosomal cross results in a phenotype ratio of 3:1?

1. BBx bb
2. Bb x bb
3. Bb x Bb

Which autosomal cross results in a genotype ratio of 1:2:1?

1. BBx bb
2. Bb x bb
3. Bb x Bb

Which autosomal cross results in a phenotype and genotype ratio of 1:1?

1. BBx bb
2. Bb x bb
3. Bb x Bb

Homework check

WB page 150 Q 27

5.5 When Genes Change

TB page 138

The penguin’s strange coloring is due to a condition called leucism, which results in a loss of pigmentation.

“This is a leucistic penguin,” Adams says. “Its cells don’t create melanin anymore so its black feathers become this yellow and creamy color.”

https://petapixel.com/2021/02/18/wildlife-photographer-captures-never-before-seen-yellow-penguin/

What is a mutation?

Keywords

• Mutation = a change in a gene
  
  
  
• Tumour = an uncontrolled growth of cells.

01:34

In DNA damage, a T base bonds with another T base on the same strand instead of with...

1. a C on the same strand
2. an A on the same strand
3. a C on the opposite strand
4. an A on the opposite strand

01:48

What causes a mutation?

1. The repair of DNA
2. A mistake in the repair of DNA

02:24

Which is the incorrect statement?

1. UV damages the immune system
2. The immune system prevents mutations
3. The immune system helps fight cancer
4. UV damages DNA

Mutations

A change in a gene

• Body cells: only you
• Gametes (sex cells): transferred
  to next generations

Workbook page 152

questions 30 - 32 and 34

Today

1. Quiz
2. Inherited diseases

• What is the difference between dominant and recessive diseases?
• Solving inheritance problems involving inherited diseases.

Mutations

A change in a gene

• Body cells: only you
• Gametes (sex cells): transferred
  to next generations

Inherited diseases

• Dominant diseases
• Recessive diseases

What is a dominant allele?

What is a 'carrier' person? (hint: use the word allele in your answer)

Which genetic disease is more dangerous?

1. a dominant disease
2. a recessive disease

Why is a dominant disease more dangerous?

1. You need only 1 allele to be sick
2. You need 2 alleles to be sick
3. You get an allele from both parents
4. You have a higher chance of giving it to your kids

Workbook page 153

questions 35 and 36