1. Cell division – process by which cells produce new cells

2. What you’ll learn about in this unit:
Why and how cells divide
The three types of cell division:
Binary Fission, Mitosis and Meiosis
What regulates or controls when cells start and stop dividing.
How cells specialize during their life
Mistakes that occur during division that can lead to cancer and genetic disorders

3. Key Concept: All cells come from preexisting cells – Cell Theory
Unit 5 Cell Division
Key Concept: All cells come from preexisting cells – Cell Theory

4. Cell division – process by which cells produce new cells

5. Each new cells receive a copy of the genetic material (DNA) stored in chromosomes of the parent cell

6. Chromosome Structure 2 Types of Molecules joined together
DNA (nucleic acid) 1 in each chromosome
Histones (protein) 1000’s in each chromosome

7. Chromosomes are made of DNA coiled around protein molecules

8. Chromosome Location in Cells
Eukaryotic cells – Nucleus
Prokaryotic cells– Cytoplasm (Nucleoid Region)

9. Chromosome Shape Eukaryotic cells - Rod , Linear
Prokaryotic cells – Circular

10. Two Types of Chromosomes
Autosomes – carry genes not related to sex
Sex chromosomes – carry genes for sex traits
XX – Female XY - Male

11. Homologous Chromosomes

12. Body Cells and Sex Cells have different numbers of chromosomes
Somatic / Body Cells
Have 2 copies of each chromosome 1 from each parent – Diploid 2n
Members of a species have the same chromosome number in body cells
Ex. Humans Dogs Fruit Flies 4
Made through Mitosis

13. Body Cells and Sex Cells have different numbers of chromsomes
Gametes / Sex Cells
Have only 1 copy of each chromosome - Haploid 1n
Made through Meiosis

14. Haploid 1n Diploid 2n

15. 3 Major Types of Cell Division

16. Binary Fission * Used by Prokaryotes and some unicellular Protists
* Makes two genetically identical daughter cells
(clones)
Form of asexual reproduction

17. Mitosis Used by eukaryotic organisms
Process of making somatic/ body cells
Ex Skin , nerve, muscle
Used for growth, to repair damage or replace worn out cells
2 Daughter cells are created from the division on one parent cell
Daughter cells are genetically identical to the parent cell –they “inherit” an exact copy of the same chromosomes

18. Mitotic Cell Division X= Number of chromosomes Parent Cell X X
Daughter Cells X X

19. Meiosis Used by sexually reproducing eukaryotics.
Process of making gametes/ sex cells.
4 new cells are made from one parent cell.
New cells are NOT genetically identical to the parent cell.
Daughter cells have only half the number of chromosomes as the parent cell.
Also known as Reduction Division

20. Meiotic Cell Division X= Number of chromosomes Parent Cell X
Daughter Cells
½ X
½ X
½ X
½ X

21. Gametes are made in Meiosis

22. Chromosome number is different in sex cells and body cells
Haploid (n) cells have only 1 copy of each type of chromosome
- Sex cells are haploid
Diploid (2n) cells have 2 copies of each type of chromosome.
Body cells are diploid.

23. DNA in threadlike form – Chromatin
DNA in coiled /condensed form - Chromosome

24. The zygote (fertilized egg) doubles its chromosomes and divides millions of times resulting in growth. Each new cell receives a complete set of all the chromosomes

25. Meiosis occurs in the testicles and ovaries.
Produces sex cells: egg and sperm.
Sex cells are what transport/carry the parents DNA to their kids
body cells
sex cells (sperm)
sex cells (egg)

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

27. Chromosome number must be maintained in animals.
Many plants have more than two copies of each chromosome.
Mitosis and meiosis are types of nuclear division that make different types of cells.
Mitosis makes more diploid cells.

28. Meiosis makes haploid cells from diploid cells.
Meiosis occurs in sex cells.
Meiosis produces gametes.

29. Cell Division Vocabulary
diploid (2N) – a cell with 2 chromosome sets in each of its cells; all body (somatic) cells
haploid (N) – a cell with 1 chromosome set in each of its cells; all gametes (sperm, eggs)