Chromosomes

• Biologie
• Middelbare school
• havo
• Leerjaar 2

Welcome!

Today: 

Discussing homework, page 102

Questions about last lesson

Discussing chromosomes (5.2), page 108

Making exercises

Has the genotype or phenotype changed?

Someone got skin cancer through sun radiation. Is the genotype or phenotype changed (or both)?

A pollen (sex cell) of a tree has 64 chromosomes. How many chromosomes do the body cells have?

What changes more throughout your life?

1. Phenotype
2. Genotype

What are we going to learn?

We will be learning:

How you get 50% of your genetic material from one parent. 

How sex is determined by chromosomes. 

How every child is different thanks to sexual reproduction. 

Cell -> DNA

A body cell has a nucleus, this nucleus contains 46 chromosomes. These are long strings of DNA. These contain all your genetic material: your genotype. A gene is a piece of DNA that says something about one characteristic.

Chromsomes

Each human body cell has 46 chromosomes. These occur in pairs. These pairs have the same genes, but different variations on them. You also have your sex chromosomes, which determine your gender.

You get one of the chromsomes of the pair from the sperm, and one from the egg. 

Variants of genes

Sex cells

Sex cells can develop from body cells. These cells play a major role in reproduction. The division of a body cell into a sex cell is called meiosis.

Because the chromosomes that are passed along to a certain sex cell is different, you get variation in genotype.

Let's get started with the exercises!

Make the exercises of paragraph 5.2, starting on page 111. You don't need to make exercise 6. 

You work in silence for the first 10 minutes. 

Een menselijke cel heeft 23 chromosomen, dit is een...

1. Lichaamscel
2. Geslachtscel

Waardoor word het geslacht van een kind bepaald?

1. Zaadcel
2. Eicel
3. Zaadcel & eicel
4. Geen van beide

De chromosomen van hetzelfde paar hebben wel dezelfde genen, maar andere varianten.

1. Juist
2. Onjuist