Genetics & Inheritance

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

Chapter 1

Traits in pairs

Name one trait (=eigenschap) that you inherited (=geërfd) from one of your parents

Which of the following is a trait(s) of a human?

Sharp fingernails

Yes

No

Which of the following is a trait(s) of a human?

Scaly skin

Yes

No

Which of the following is a trait(s) of a human?

Short toes

Yes

No

Why is it important to talk about traits and inheritance?

Case study

After this lesson...

...you can describe how traits are passed on from parents to children 

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

Traits

Many traits are passed on from parents to children

But how does that happen?

Phenotype 

Visible traits --> phenotype

Phenotype results from information in cells

Where in cells do you find information?

DNA

Stands for: Deoxyribonucleic acid

A, T, C, G (nucleotides)

Bundled up in structures called chromosomes

Chromosomes

23 chromosome pairs in humans 

1 chromosome from mother, 1 from father 

22 pairs autosomes (numbered), 

1 pair sex chromosomes

XX --> female

XY --> Male

How many chromosomes are in sex cells?

Genotype & Fenotype

Genes on DNA --> genotype

Expression of gene --> fenotype

Fenotype can also be changed by environment

Make assignment chromosomes and genes

4, 5, 6

Genes

Not always active

- Growth

- Lactose intolerance

Variants of a trait --> allele

- Brown/blue eyes

- Straight/curly hair

Make assignments Chapter 1

On Somtoday

What is genotype?

What is fenotype?

When you are male, you have ... as sex chromosomes

1. XX
2. XY

A person with Down's syndrome has ...

1. An extra chromosome 21
2. An extra sex chromosome
3. One sex chromosome short
4. One chromosome 21 short

What if you have an extra sex chromosome?

1. It's lethal, you cannot live with that
2. Nothing has changed
3. You are definitely female
4. You are intersexual

Chapter 2

Reproduction

After this lesson

You can describe different types of reproduction and explain the differences between them

Asexual reproduction

Asexual reproduction

Sexual reproduction

Sexual reproduction

n = number of chromosomes

Body cells are always 2n!

Formation of sex cells (meiosis):

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

When gametes (sex cells) fuse:

n (sperm) + n (egg) --> 2n (zygote)

Twins

Non-Identical

Make assignments chapter 2