5.1 Genotype and phenotype

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 3

5. It runs in the family

Heredity and evolution

What do you think of when you hear the title: 'It runs in the family'?

Which characteristics are passed on from one generation to the next?

5. It runs in the family

On inheritance, family trees, genetics and DNA

5.1 Pass it on!

How did you inherit characteristics from your parents?

Why do some inherited characteristics not show?

What are chromosomes?

Why do siblings look similar to their parents and each other?

AIM = 

5.1.1 You can describe what the genotype and phenotype are.

5.1.2 You can explain that cells only use the hereditary information that they need.

Body cells, chromosomes, DNA

DNA and genes

DNA contains information about thousands of characteristics.

GENE = 

a pieces of DNA that contain the information for one characteristic.

                                                        Each body cell contains all the 
                                                   genes but not all genes are active

To inherit = to receive a characteristic from an ancestor by genetic transmission. 

• Genotype = the information for an organism’s complete hereditary characteristics
• Phenotype = visible and invisible physical characteristics of an organism

           Phenotype = genotype + environmental factors. 

Environmental change can also have an effect on the phenotype of us humans. Describe an example when your body would change under changing conditions

Phenotype = genotype + environmental influences

The phenotype changes…

…but the genotype doesn’t.

Chromosomes

Inside the cell nucleus are structures called chromosomes

They are DNA strands and contain all of your inherited characteristics

Normal body cell: 46 chromosomes

Organised in 23 homologous pairs. 

Each pair has two matching chromosomes. 

How can you tell this is a male karyotype? 

Sperm and egg cells only have 23 chromosomes. Explain why (TIP: think about what happens
during fertilisation).

TALKING EXERCISE

Discuss with your classmate...

what would happen if a sex cell (egg/sperm cell) had 46 chromosomes, just like a normal body cell. What would this 

mean for the fertilised egg cell? And for the next generation?

Let's do a little inventory..

Which characteristics do you have?

Make sure you write down the results

I can roll my tongue

YES

NO

Which hand do you write with?

LEFT

RIGHT

NO PREFERENCE

Hand clasping?

LET'S PRACTICE

Most people on the Solomon Islands (in the Pacific Ocean) have dark skin and dark hair. Sometimes, however, a child is born with very light-coloured hair.

Figure it out in exercise 1

Make exercise 1-10 in your notebook

Finish it before next lesson

LET'S PRACTISE.

A picture and karyotype of a pea plant from the species Chamaecrista fasciculata. 

3. How many chromosomes do you count?

4. Can the number of chromosomes in a pollen cell of Chamaecrista be even, uneven or both? Explain your answer! 

If you look at this persons hair..

1. Phenotype
2. Genotype
3. Phenotype en Genotype

The eye color of these people are.

1. Phenotype
2. Genotype
3. Phenotype en Genotype

Can you change the phenotype of in individual?

1. Yes
2. No
3. Don't know

Put in the correct order,
from small to big.

1. cell - chromosome - DNA - gene
2. gene - chromosome - DNA - cell
3. gene - chromosome -cell - DNA
4. gene - DNA - chromosome - cell

Zet de juiste omschrijving bij het juiste begrip.

chromosoom

gen

allel

thread of DNA with hereditary information

part of the DNA containing the information for one characteristic

type of gene

Which one is correct?

1. Phenotype = genotype + environment
2. Environment = genotype + phenotype
3. Genotype = phenotype + environment

Mathilde is having her hair dyed at the hairdresser. Does this change her
En haar fenotype?

1. genotype wel fenotype niet
2. genotype niet fenotype wel
3. genotype niet fenotype niet
4. genotype wel fenotype wel

Heeft een vlinder hetzelfde fenotype als de rups waaruit hij is ontstaan? En hetzelfde genotype?

1. alleen hetzelfde fenotype
2. alleen hetzelfde genotype
3. zowel hetzelfde fenotype als hetzelfde genotype

Hoeveel chromosomenparen hebben de meeste mensen in hun lichaamscellen?

1. 22
2. 23
3. 44
4. 46

Hoeveel erfelijk materiaal heeft een gameet (geslachtscel), ten opzichte van een gewone cel.

1. Net zoveel
2. 1/2
3. 1/4
4. 2x zoveel