1. What is meiosis and why is it important in reproduction?
Starter
Choose a key word from the list below and describe it in your own words.
Done? Find out what you neighbour did.
Try another.
Scientific paper
Nuclear membrane
Rebops!?
Double helix
mitosis
cytoplasm
mitochondria

2. What is meiosis and why is it important in reproduction?
Starter
Complete your revision card for mitosis
Rebops!?

3. Learning Outcomes
1) Recall that meiosis is a type of cell division that produces gametes.
2) Explain why gametes only contain half the chromosome number of the parent cell.
3) Recall that a zygote contains a set of chromosomes from each parent.
4) Outline how sexual reproduction gives rise to variation.

4. Call my Bluff
Work in teams to come up with 2 alternative definitions for your key word. You win, if no one guesses the right answer.

5. Call my Bluff
Gamete:
Meiosis:
Zygote:
Chromatid:
Organelle

6. Call my Bluff
Gamete: these are sex cells i.e. Sperm and eggs. They have half the number of chromosomes compared to normal body cells.
Meiosis: the process by which sex cells are formed with half the number of chromosomes to a normal cell.
Zygote: a cell produced by the joining of an egg cell and sperm cell.
Chromatid: each of the pair of the chromosomes that are made when DNA doubles during mitosis.
Organelle – a specialised structure within a cell.

7. Genetic information Inside each cell is a nucleus.
Inside the nucleus are 46 chromosomes.
Each chromosome contains thousands of genes.
Each gene codes for a protein.
Chromosomes are made of a chemical called DNA.
Largest
Smallest

8. In a normal body cell you have 23 PAIRS of chromosomes

9. Downs Syndrome

10. Fertilisation
What happens in fertilisation?

11. If 2 complete cells combined how many chromosomes would the zygote (embryo) have ?46 46 92
What is a zygote?

12. 92 chromosomes is FAR too many
The embryo has to have 46 chromosomes .
To get this the egg and sperm must have 23 each. 23 23 46

13. BUT the question is...
If our cells all have 2 sets of chromosomes how do we make gametes (sex cells) with only 1 set? THINK – PAIR – SHARE

14. Gametes have 23 chromosomes

15. Stages of Meiosis
Meiosis only happens in the testes and ovaries to produce eggs and sperm.
During Meiosis as in mitosis, all the genetic information doubles.
In meiosis the parent cells then split twice.
This produces 4 daughter cells which have 23 chromosomes from the parent. (half the normal number) These are either sperm cells or egg cells.

16. Tasks: 1) complete the meiosis cartoon, cut and paste exercise. 8 mins
2) Complete the mix and match card sort for mitosis and meiosis. 5 mins
3) Complete the past paper questions on mitosis and meiosis. 5 mins
4) Create a concept map comparing meiosis and mitosis.
5) Write your own exam style question for mitosis and meiosis

17. Plenary Mitosis or Meiosis
Produces clones

18. Mitosis or Meiosis
Produces gametes

19. Mitosis or Meiosis
Makes 4 daughter cells

20. Mitosis or Meiosis
Important for repair of damaged parts of the body

21. Mitosis or Meiosis
Used by bacteria to reproduce.

22. Mitosis or Meiosis
Makes 2 daughter cells

23. If all our cells are genetically identical, why do we have so many different organs?
THINK, PAIR, SHARE

24. Stem cells and differentiation.
What is a major difference between plants and adult humans?

25. Key Word Card Sort

26. solve the anagrams by rearranging the letters
Mitosis & Meiosis
solve the anagrams by rearranging the letters
clue letters
things you find in a cell a gel loner
where the chromosomes are clue sun
type of cell division i miss to
type of cell division some i is
joining of egg and sperm airline fist to
sex cell eat gem
how new cells are made sliced violin
the new cell cat hurdle leg
the original cell all percent
found in the nucleus smooch more