2. Cell Reproduction

3. How does the cell know how to divide?
Cell Division
Why do cells divide?
Reproduction
Growth
Repair
Volume too large for surface area (restricts diffusion)
How does the cell know how to divide?
The DNA has the instructions for all of the cell’s activities.

4. Types of Reproduction
Asexual reproduction is production of offspring from 1 parent. The genetic material is identical to the parent (DNA replication).
Sexual reproduction is the formation of a new individual from the union of 2 sex cells (gametes). The offspring will have the traits of both parents.

5. Methods of Asexual Reproduction
binary fission –
DNA replicates and cell divides
ex: prokaryotes

6. 2. spore formation –
single cell reproductive structures produced by organisms such as fungi

7. 3. budding -
cell nucleus and cytoplasm divide unequally, the smaller “bud” pinches off
ex: yeast, hydra

8. 4. vegetative propagation -
“runners” - plants send out horizontal stems that take root when they touch the ground
ex: strawberries

9. DNA + protein → chromatin → chromosome
In preparation for cell division, DNA clumps together and shortens to form chromosomes.
DNA + protein → chromatin → chromosome

10. chromatin
centromere
Chromosome
Each ½ = chromatid

11. Each kind of eukaryotic organism has a specific # of chromosomes in its body cells (somatic cells).
ex: humans 46, corn 20
When a cell reproduces, each daughter cell will need a full set of chromosomes. These #’s are pairs of chromosomes.
ex: Humans get one of each pair (23) from mother and one of each pair from father.

14. THE CELL CYCLE

15. THE CELL CYCLE
The events that occur during the cell cycle are a continuous process.
The cell cycle can be broken down into two major steps:
interphase and
mitosis

16. 1. Interphase
Cell grows
Produces new organelles
Copies DNA

17. 2. Mitosis
Mitosis is the division of the nucleus or genetic material of a cell.
Mitosis can be broken down into four phases:
Prophase
Metaphase
Anaphase
Telophase

18. Mitosis is followed by the division of the cytoplasm, cytokinesis.