1. Meiosis
Learning Objectives

2. Learning Outcomes

3. Key Words gamete – A male or female reproductive cell – sperm or egg.
gene – The unit of inheritance.
homologous – Two chromosomes containing the same type of genes and which pair up during meiosis.
meiosis – The type of cell division that produces four unique daughter cells (gametes).
mitosis – The type of cell division that produces two identical daughter cells.
mutation – A random change in the genetic code of a cell.
spindle – A network of tiny fibres that attach to chromosomes during cell division and separate them.
zygote – A fertilized egg cell.

4. Meiosis Cell division to produce gametes. Normal cell is Diploid
Gamete is Haploid – in humans contains only 23 chromosomes.

5. What are sex cells?
Sex cells in animals and plants are called gametes. In animals, the gametes are eggs (ova) and sperm.
lots of mitochondria for providing energy
flexible tail for swimming
food source in cytoplasm for embryo
enzymes to digest egg cell membrane
protective outer cell layers

6. Two Stages The homologous pairs of chromosomes separate into 2 cells.
The chromatids in each of the 2 cells separate in a mitotic style division.
4 daughter cells are produced.
In humans each contains 23 chromosomes.
i.e. 4 sperm cells
or 4 egg cells

7. What happens during meiosis?
Teacher notes
This nine-stage interactive animation shows how a cell divides by mitosis. It assumes that students are familiar with the process of mitosis and the key terms it introduces (chromatids, centromere, nuclear envelope, spindle fibres). Suitable prompts could include:
Start: What part of the body will meiosis take place?
Stage 1: What is each strand of a duplicated chromosome called?
Stage 2: Where are chromatids joined?
Stage 3: How do chromosomes align in the middle of the cell?
Stage 4: What happens to homologous pairs to increase genetic variation?
Stage 5: How does the first division of meiosis compare to the first division of mitosis?
Stage 6: How many chromosomes does each cell contain?
Stage 7: How do the two cells compare with each other?
Stage 8: How does the first division of meiosis compare to the first division of mitosis?
Stage 9: How do the four cells compare with the original cell?

8. The stages of meiosis Teacher notes
This ordering activity could be used as a plenary or revision exercise on the stages of meiosis. Mini-whiteboards could be used to make this a whole-class exercise.

9. Chromosomes during meiosis
Teacher notes
This drag and drop activity provides the opportunity for informal assessment of students’ understanding of what happens to chromosomes during meiosis.

10. Anagrams

11. Mitosis or meiosis? Teacher notes
This mitosis-or-meiosis activity could be used as a plenary or revision exercise on the two types of cell division. Coloured traffic light cards (green = mitosis, yellow = don’t know, red = meiosis) could be used to make this a whole-class exercise.

12. Differences between mitosis and meiosis
Number of chromosomes?
Meiosis = 23
Mitosis = 46
Diploid or haploid?
Meiosis = haploid
Mitosis = diploid

13. Differences between mitosis and meiosis
Clones?
Meiosis = no
Mitosis = yes
Used for?
Meiosis = production of gametes
Mitosis = growth and repair
Asexual or sexual reproduction?
Meiosis = sexual
Mitosis = asexual