Dominant and recessive

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

Planning

Homework check 

Video to remember alleles and genes

Explanation 5.8 dominant and recessive

 You can describe what homozygous, heterozygous, dominant and recessive mean.

Figure 1 homozygous and heterozygous

Heterozygous

1 allele is dominant 

1 allele is recessive

Dominant: ''strong'' allele will be expressed in phenotype

Recessive: will not be expressed in phenotype

The black bull is heterozygous 

Which allele is dominant?

1. allele for black fur
2. allele for red fur

Alleles are indicated with letters

Gene: fur colour

Allele: black dominant --> A

Allele: red recessive --> a

Dominant allele with CAPITAL LETTER 

Recessive allele with lowercase letter

Genotype red bull: aa

Genotype black bull: Aa

Lady 3 is heterozygous for hair colour, what is her genotype?

1. aa
2. AA
3. Aa

Time to work!

Read page 164 and 165

Make question 1 to 3

SO 5.1 - 5.2 - 5.3 - 5.8 (1x) 

5.1

• you can describe genotype and phenotype
• you can explain that cells only use the hereditary information that they need 

5.2

• You can explain how each of the parents provides 50% of the chromosomes
• You can say how the sex of a human is determined by sex chromosomes
• You can explain how sexual reproduction causes variation in genotypes 

5.3

• You can describe what genes and alleles are
• You can describe what a mutation is
• You can describe what cancer is 

5.8

You can describe what homozygous, heterozygous, dominant and recessive mean