1. AQA Biology AS Level Unit 2
Meiosis, Mitosis and the Cell Cycle

2. Outcomes:
Know that cell division by meiosis results in the formation of gametes.
Can describe the importance of meiosis in creating variation by independent assortment of chromosomes and crossing over.
Know that cell division by mitosis results in an increase in number of identical cells for growth and repair.
Identify and name the stages of mitosis in diagrams and photomicrographs.
Describe the cell cycle and relate it to an understanding of cancer and its treatment.

3. Replication of chromosomes occurs prior to division
Homologous chromosomes
centromere
chromosome
chromatids

4. Meiosis consists of two divisions

5. Gametes are formed by meiosis:
Homologous chromosomes associate

6. Outcomes:
Know that cell division by meiosis results in the formation of gametes.
Describe the importance of meiosis in creating variation by independent assortment of chromosomes and crossing over.
Know that cell division by mitosis results in an increase in number of identical cells for growth and repair.
Identify and name the stages of mitosis in diagrams and photomicrographs.
Describe the cell cycle and relate it to an understanding of cancer and its treatment.

7. Independent segregation increases variation
Random assortment
in meiosis II
Random assortment
in meiosis I
paternal
maternal

8. or paternal maternal Random assortment in meiosis II Random assortment

9. Crossing over increases variation
recombinant
chromosome
chiasma
In the first division of meiosis the homologous chromosomes associate

10. Crossing over increases variationB G B g b G b g
B, G
B, g
b, G
b, g
All gametes have a different combination of alleles on the chromosomes

11. Outcomes:
Know that cell division by meiosis results in the formation of gametes.
Can describe the importance of meiosis in creating variation by independent assortment of chromosomes and crossing over.
Know that cell division by mitosis results in an increase in number of identical cells for growth and repair.
Identify and name the stages of mitosis in diagrams and photomicrographs.
Describe the cell cycle and relate it to an understanding of cancer and its treatment.

12. Mitosis produces two identical daughter cells.
metaphase
prophase
anaphase
interphase
telophase
cytoplasmic division (cytokinesis)

13. Stages of mitosis interphase M prophase I T O S metaphase anaphase
telophase
cytokinesis
Chromosomes invisible; DNA replicates
Chromosomes appear, nucleus disappears
Chromatids pulled to poles
Cytoplasmic division
Chromosomes at equator, spindle forms
Chromatids at poles, nucleus reforms

14. Outcomes:
Know that cell division by meiosis results in the formation of gametes.
Can describe the importance of meiosis in creating variation by independent assortment of chromosomes and crossing over.
Know that cell division by mitosis results in an increase in number of identical cells for growth and repair.
Identify and name the stages of mitosis in diagrams and photomicrographs.
Describe the cell cycle and relate it to an understanding of cancer and its treatment.

15. The cell cycle interphase G1: Growth of daughter cell
Duplication of organelles other than nucleus
S: Replication of DNA
G2: Cell checks DNA and makes any repairs. Cell prepares for division
cytoplasmic division
nuclear division
prophase
metaphase
anaphase
telophase

16. Cancer

17. Summary
Meoisis produces haploid gametes that are genetically different. Variation is further increased by independent segregation of chromosomes and crossing over forming recombinant chromosomes.
Mitosis is the nuclear division which produces 2 genetically identical, diploid cells. It consists of prophase, metaphase, anaphase and telophase.
Cell cycle consists of interphase, nuclear division (mitosis or meiosis) and cytplasmic division (cytokinesis).
Cancer is caused by mutation of genes that regulate the cell cycle and treatment is designed to inhibit cell division.