Single traits

• Biologie
• Middelbare school
• havo
• Leerjaar 2,3

Welcome!

Today:

Discussing homework 

Explanation about inheriting single traits

Answering/discussing excercises 

What are we going to learn today?

We are going to learn:

the difference between genotype and phenotype. 

What genes and alleles are.

How traits are being passed over from generation to generation.

How traits can also skip a generation. 

Genotype/phenotype

Your appearance is called your phenotype. For the most part this is determined by your genotype, your genetic material. However, you can change your phenotype by altering your appearance, but this doesn't change your genotype. 

Changing your phenotype

Checkpoint 1

Please make questions 1 and 2 in your workbook. 

Chromosomes

Chromosome pair 

Alleles

Both chromosomes in a pair have the same genes, but the variations, alleles, are different. 

Some alleles are dominant (A), when they are present in a gene, they always become visible. Recessive alleles (a), only become visible when there isn't a dominant allele. 

Alleles

For every trait there are at least two alleles present, in every chromosome from the same pair. So you always have 2 letters. When you have two of the same alleles (AA or aa), it is called homozygous. When you have two different alleles (Aa), it is called heterozygous. 

P-generation

Inheriting traits always start at a parent generation (P-generation). You always have to know their genotype about the trait. You always have to write it down as: (genotype parent 1) x (genotype parent 2)

For example: Aa x aa

2 labradors are going to mate. One has a brown fur, the other one blonde. Brown fur is dominant over blonde fur. Both dogs are homozygous. What is the genotype of the parents?

1. AA x aa
2. Aa x AA
3. Aa x aa
4. Aa x Aa

What genotype does the F1 have? (first generation offspring)

P = AA x aa

What is the fenotype of the F2? (second generation offspring)

F1 = Aa x Aa

Exercises 

Please start with questions 1 through 9. Which will be homework for next lesson! 

See you all next week! 😊