Ch.1 Traits in pairs

What to do:
  • Read everything well!
  • Make a glossary (begrippenlijst) from all terms you see in the text. 
  • Answer all questions!

  • You can ask me questions when I'm done explaining to the rest of the class.
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Slide 1: Slide
BiologieMiddelbare schoolvwoLeerjaar 3

This lesson contains 26 slides, with interactive quizzes, text slides and 1 video.

time-iconLesson duration is: 30 min

Items in this lesson

What to do:
  • Read everything well!
  • Make a glossary (begrippenlijst) from all terms you see in the text. 
  • Answer all questions!

  • You can ask me questions when I'm done explaining to the rest of the class.

Slide 1 - Slide

At the end of this lesson you can:
  • …describe what genotypes and phenotypes are.
  • …name the characteristics of chromosomes.
  • ...describe the difference between genes and alleles.

Slide 2 - Slide

phenotype (uiterlijk)
Everyone knows they look their parents. They look a little like their father and a little like their mother. At the same time you are not half of either. You are unique.

Your appearance (visible characteristics) is called your ​phenotype​. These are the ​traits we can see on an organism.

Phenotype: the visible traits (eigenschappen) of an organism.



Slide 3 - Slide

genotype (genetisch materiaal)
The basis for almost all traits is your ​genotype​. Your genotype is a combination of all traits that you can find on your ​DNA​.

Genotype: the DNA sequence (code) for hereditary (erfelijke) characteristics in an organism.


Slide 4 - Slide

genotype vs fenotype
You phenotype can change by influences from your environment (omgeving). By for example dying your hair a different colour. 

Your genotype can not change. 

Phenotype = Genotype + environment


The information for your hereditary characteristics is your DNA. But what exactly is DNA?



Slide 5 - Slide

genotype
phenotype
XY chromosomes
cannot change!
you inherit this
can sometimes change during your life
you do not inherit this
a scar
Is not always visible

Slide 6 - Drag question

Identical twins do have the same genotype but not necessarily the same phenotype
A
true
B
false

Slide 7 - Quiz

DNA: a long thin thread of a code that contains the information for all your hereditary traits. The building blocks can make many different codes for many different traits. 

Slide 8 - Slide

A segment of DNA has the following order of nucleotides : ATTGGCAGTA. What is the order of nucleotides on the other strand?

Slide 9 - Open question

Chromosomes
The long thin threads of DNA are bundled together into  chromosomes (Fig. 1)

Chromosomes are located in the nucleus of every cell in your body (except red blood cells).
The chromosomes contain all information for all you hereditary traits. (Fig. 2)







Fig. 1
Fig. 2

Slide 10 - Slide

Where in your cells can you find chromosomes?

Slide 11 - Open question

Body cells
The nucleus of the body cells of a human:
(cells that make up the body, for 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.



Slide 12 - Slide

Body cells
The first 22 pairs of chromosomes are present in every human (called autosomes). 
The 23rd pair is special because they are not always the same. These are the sex chromosomes.
Sex chromosomes determine whether your genetic sex is male or female. 

Males have X-Y chromosomes
Females X-X chromosomes. 

Slide 13 - Slide

Sex cells
Sex cells are different than the body cells. 
Sex cells contain 23 chromosomes. There are no pairs. 

This is because the 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 14 - Slide

How many chromosomes do you have in each nucleus?
A
44
B
46
C
48
D
23

Slide 15 - Quiz

How many sex chromosomes do you have in a muscle cell?
A
0
B
1
C
2
D
46

Slide 16 - Quiz

How many X chromosomes do you have in a skin cell?
A
0
B
1
C
2
D
46

Slide 17 - Quiz

A cell with an X chromosome and a Y chromosome, can be a
A
muscle cell
B
sperm cell
C
egg cell
D
no cell

Slide 18 - Quiz

Genes
Each chromosome contains the information of a large number of hereditary traits. 
A part of a chromosome that contains the information for one trait is called a gene.

Each chromosome contains lots of genes. 
Every ​body cell​ ​in an organism has all the DNA (and all the genes) to build a complete organism. This means that all genes can be found in every cell. 
Why do we still look different then?

Slide 19 - Slide

Genes
First it is important to understand that genes are not always active. Genes can be turned on or off. That is why your body changes over time. 

Genes can be (de-)activated by many things.
For example: 
-Gene to make you grow. Activated by hormones. No hormones? Gene not active 



Slide 20 - Slide

Alleles
Secondly many genes have ​variants​ of the same trait. These variants are called ​alleles​.

A few examples:
- Everyone has the ​gene​ for eye colour. There are two ​alleles​ for eye colour, such as
blue or brown. ‘Eye colour’ is the gene, ‘blue’ and ‘brown’ are alleles;
- Everyone has a ​gene f​or hairstyle.‘Straight hair’ and ‘curly hair’ are​ alleles ​of this gene.



Slide 21 - Slide

Slide 22 - Video

Oliver says: 'all humans have the same genes, but not the same alleles'. Charley says: 'all humans have the same alleles, but not the same genes'. Who is right?
A
Oliver
B
Charley
C
They both are
D
They are both wrong

Slide 23 - Quiz

Is it a gene or an allele?
GENE
ALLELE
skin colour
curly hair
flower colour
blue eyes
blood type
type A blood
colour-blindness
hair type
short wings in a fruit fly

Slide 24 - Drag question

Write down any questions you have or parts you still find difficult.

Slide 25 - Open question

Done?
1. Make the exercises chapter 1 'Genes and alleles' in the document @studiewijzer 

2. Make exercises basic 5.1 at Malmberg if you haven't done that yet.

3. Start reading chapter 2 @booklet

4. Make the glossary (begrippenlijst) if you haven't yet. 

Slide 26 - Slide