5.1 Genetics

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

PLANNING

• Discuss next step & the planning for biology
• Start Chapter 5

WHAT WILL BE THE NEXT TEST? 

Option 1: Test on Chapter 4 + 7 (as planned for this week) when we get back to school, in the meantime we already start discussing chapter 5. 

Option 2: Test on Chapter 5 + 7 when we are back in school & have finished chapter 5. BT4+7 & BT5 would be cancelled; instead we would have BT5+7 (4x)

WHAT WILL BE THE NEXT TEST? 

• You all have to vote (together with the other 3TTO class) for the option you prefer. 
• The option with the most votes 'wins' (democracy, yay). 
• You can find the poll in SOM! 

What do you think about when you hear the term; 'inheritance'?

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

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

• Genotype = complete set of all inherited characteristics. 
• Phenotype = set of characteristics that are seen/expressed. 

Phenotype = genotype + pattern of gene expression + environmental factors. 

We will learn more about this later this chapter

Do you remember the term 'homologous structures' from the chapter on evolution?
What are homologous structures?

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).

LET'S PRACTISE. 

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.

1. Is this child's phenotype visible in the

picture? 

2. Is this child's dark skin and light hair part of his genotype? 

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! 

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?