BS2 - Chromosomes

Today
Recap 5.1
Checking homework
Explanation 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.
Self-study 
End

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Slide 1: Slide
BiologieMiddelbare schoolvwoLeerjaar 3

This lesson contains 23 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 45 min

Items in this lesson

Today
Recap 5.1
Checking homework
Explanation 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.
Self-study 
End

Slide 1 - Slide

Which one is correct?
A
Phenotype = genotype + environment
B
Environment = genotype + phenotype
C
Genotype = phenotype + environment

Slide 2 - Quiz

If you look at this persons hair..
A
Phenotype
B
Genotype
C
Phenotype en Genotype

Slide 3 - Quiz

Put in the correct order,
from small to big.
A
cell - chromosome - DNA - gene
B
gene - chromosome - DNA - cell
C
gene - chromosome -cell - DNA
D
gene - DNA - chromosome - cell

Slide 4 - Quiz

Slide 5 - Slide

Body cells
The nucleus of the body cells of a human:
(ex. liver cells, skin cells, muscle cells etc) contain 46 chromosomes. 

Every chromosome carries the information for different hereditary traits. 
Chromosomes occur in pairs. 
Two chromosomes in a pair match; they carry information for the same traits. 
There are 23 pairs.
Pair 23 are the sex chromosomes. 



Slide 6 - Slide

Pair 23 are the sex chromosomes. 

Slide 7 - Slide

Chromosomes
Contain DNA

Bundled DNA-fibre wrapped around histones

23 chromosome pairs in human body cells

Slide 8 - Slide

Sex cells
Sex cells are different than the body cells.
 
Sex cells contain 23 chromosomes. There are no pairs. Ex. Sperm cell and egg cell

Nucleus of the sex cell of a man and the nucleus of the sex cell of a woman fuse together. 
This way the child has 50% of its genetic information form the father and 50% of the mother. 

Pair 23 will determine the sex of the child. This depends of chromosome 23 of the spermcell  is a X or a Y chromosome. 

Slide 9 - Slide

How many chromosomes?
Male or female?

Slide 10 - Slide

45, X

Slide 11 - Slide

How many chromosomes?
Male or female?

Slide 12 - Slide

47, XY, +21 

Slide 13 - Slide

fig. 3 Different information on a chromosome pair

Slide 14 - Slide

Variation in genes
  • Sex cells = no pairs of chromosomes. 
  • only 1 copy of the chromosome ends up in the egg or sperm cell.
  • result: variation in genotypes 

Slide 15 - Slide

Variation in genotype
  • Due to sexual reproduction.
  • father 1/2 and mother 1/2 contribute 1 copy of chromosome.
  • Chance/coincidence!

Slide 16 - Slide

Each human being has 46 chromosomes. How many did you get from your mother?
A
46
B
23
C
22
D
45

Slide 17 - Quiz

A person containing an XY is a...
A
man
B
woman

Slide 18 - Quiz

A person containing the same copy of a sex chromosome is a...
A
man
B
woman

Slide 19 - Quiz

You have 23 sex chromosomes in your body.
A
True
B
False

Slide 20 - Quiz

Slide 21 - Slide

Write down the sex chromosomes of someone who is intersex.

Slide 22 - Open question

Let's practice 
Read basics 5.2 Chromosomes
Hihglight all concepts and their defintions 
Make the assignments 1 to 9, yes 6 as well
Extra challenge: assignment 10+11
timer
5:00

Slide 23 - Slide