1. Mitosis and Meiosis

2. THE CELL CYCLE

3. Ratio of Surface Area to Volume
Cellular Reproduction
Cellular Growth
Ratio of Surface Area to Volume

4. Cellular Reproduction
Cellular Growth
As the cell grows, its volume increases much more rapidly than the surface area.
The cell might have difficulty supplying nutrients and expelling enough waste products.

5. The cell cycle has four main stages.
The cell cycle is a regular pattern of growth, DNA replication, growth again and cell division.

6. Chromosome number must be maintained in animals.
Many plants have more than two copies of each chromosome.

7. MITOSIS

8. Mitosis and cytokinesis.
Parent cell
centrioles
spindle fibers
centrosome
nucleus with
DNA
Interphase prepares the cell to divide.
During interphase, the DNA is duplicated.

9. PROPHASE
During prophase, chromosomes condense and spindle fibers form at the centrioles.

10. During metaphase, chromosomes line up in the middle of the cell.

11. ANAPHASE
During anaphase, sister chromatids separate to opposite sides of the cell.

12. TELOPHASE
During telophase, the new nuclei form and chromosomes begin to uncoil.

13. In animal cells, the membrane pinches closed.
Cytokinesis differs in animal and plant cells.
In animal cells, the membrane pinches closed.
In plant cells, a cell plate forms.

15. Meiosis

16. KEY CONCEPT Gametes have half the number of chromosomes that body cells have.

17. Meiosis
Meiosis is the process of forming gametes also called sex cells but more commonly called egg or sperm cells
The gametes are referred to as the reproductive cells of an organism because they are formed for Sexual reproduction.
Sexual Reproduction, involves a transfer of genetic material from one parent (sperm) with another parent (egg) to form an offspring.

18. Importance of Meiosis
Offspring’s number of chromosomes must be the same number as which organism, it is.
Eg. Humans have 46 chromosomes.
If the offspring was to receive 46 from “Mom” and 46 chromosomes from “Dad”
he/she would end up with 92 chromosomes, twice the number as being considered the genetically common number for a humans.

19. You have body cells and gametes.
Body cells are also called somatic cells.
Germ cells develop into gametes.
Germ cells are located in the ovaries and testes.
Gametes are sex cells: egg and sperm.
Gametes have DNA that can be passed to offspring.
body cells
sex cells (sperm)
sex cells (egg)

20. Body cells are diploid; gametes are haploid.
Fertilization between egg and sperm occurs in sexual reproduction.
Diploid (2n) cells have two copies of every chromosome.
Body cells are diploid.
Half the chromosomes come from each parent.

21. Haploid (n) cells have one copy of every chromosome.
Gametes are haploid.
Gametes have 22 autosomes and 1 sex chromosome.

24. Meiosis II divides sister chromatids in four phases.
DNA is not replicated between meiosis I and meiosis II.