Genetics & Inheritance

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

Chapter 1

Traits in pairs

Answers questions alleles

1. An alternative version of a specific gene

2. eye colour gene, yellow and red alleles

3. No, sometimes there are multiple alleles for one gene

4. In this case yes, but most of the time it isn't the case

5. 2

6. No, alleles can be different for both chromosomes

7. The allele with advantage can take over - fixation

DNA

Deoxyribonucleic acid

A, T, C, G (nucleotides)

Contain genes -->  sequences of DNA coding for proteins

Chromosomes

Contain DNA

Bundled DNA-fibre wrapped around histones

23 chromosome pairs in humans

Chromosomes

Contain DNA

Bundled DNA-fibre wrapped around histones

23 chromosome pairs in humans (22 autosomes, 1 sex chromosome)

Genotype & Fenotype

Genes on DNA --> genotype

Expression of gene --> fenotype

 Fenotype can also be changed by environment

Genes

Not always active

- Growth

- Lactose intolerance

Variants of a trait --> allele

- Brown/blue eyes

- Straight/curly hair

Make assignments Chapter 1

On Somtoday

Chapter 2

Reproduction

What is genotype?

What is fenotype?

2 types of reproduction

Asexual reproduction

Sexual reproduction

Asexual reproduction

Asexual reproduction

Sexual reproduction

Sexual reproduction

Meiosis:

2n (diploid) --> n (haploid)

When gametes fuse:

n (sperm) + n (egg) --> 

2n (zygote)

Twins

Make assignments chapter 2