1. Cell Division and Types of Reproduction

2. Cell Division At times, cells need to divide
Divide = split and make copies
There are actually different types of cell division

3. Types of Cell Division Binary Fission Only for Prokaryotic cells
Binary = two
Fission = Split
Binary Fission = Split in two
Only for Prokaryotic cells

4. Types of Cell Division 2. Mitosis Only for Eukaryotic Cells
Makes 2 identical cells
New cell is exactly the same. Has the same DNA, does the same function (job)
Used for:
Healing
Growing
Replacing old cells

5. Stages of Mitosis
Mitosis occurs in a series of steps. These steps are:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

6. Stages of Mitosis Interphase Interphase is the longest stage
This is when the cell functions normally
The cell is growing during this time
The DNA of the cell with replicate (copy itself) and the DNA will condense into chromosomes during this stage

7. Stages of Mitosis Prophase The chromosomes condense even more.
Chromosomes can now be seen under a microscope
Nucleus dissolves and is no longer visible

8. Stages of Mitosis Metaphase
The duplicated chromosomes line up in the middle of the cell
Spindle fibers (long proteins) connect to the centre of each chromosome

9. Stages of Mitosis Anaphase
The duplicated chromosomes are pulled apart to opposite sides of the side
The chromosomes are identical and the exact same genetic information is being moved to each side of the cell

10. Stages of Mitosis Telophase
The separated chromosomes arrive at opposite ends of the cell
The nucleus begins to reform around the chromosomes
Chromosomes become less condensed.

11. Stages of Mitosis Cytokinesis
When the cell actually splits into 2 daughter cells
Animal Cells – cell membrane pinches in, in the middle to divide the 2 nuclei
Plant Cells – new cell wall forms between nuclei

12. Types of Cell Division Meiosis Only in Eukaryotic Cells
Meio = lessen (decrease)
osis = action
Meiosis = action that lessens
Only in Eukaryotic Cells
Makes sex cells
Sperm and eggs
Makes 4 different cells
Each cell has different DNA
Each cell has half of the original cell’s DNA
A human sex cell has 23 chromosomes. No pairs.

13. Stages of Meiosis
Meiosis occurs in a series of steps. These steps are:
Interphase
Prophase-1
Metaphase-1
Anaphase-1
Telophase-1
Prophase-2
Metaphase-2
Anaphase-2
Telophase-2

14. Stages of Meiosis Interphase Prophase - 1 Same as Mitosis
Chromosomes find their Homologous Pairs
Chromosome #1 pairs up with the other Chromsome #1. Chromosome #2 pairs with Chromosome #2.

15. Stages of Meiosis Metaphase - 1 Anaphase – 1
Homologous pairs line up in the middle of the cell and attach to spindle fibers
Anaphase – 1
Homologous pairs pulled to opposite sides of the cell
One side has a Chromosome number 1, the other side has the other Chromosome number one
Get different combinations of chromosomes every time meiosis occurs

16. Stages of Meiosis Telophase - 1 Prophase – 2
Cell divides into 2 daughter cells by cytokinesis
Nucleus reforms
Prophase – 2
Resting period
Nucleus dissolves

17. Stages of Meiosis Metaphase 2 Anaphase 2
Chromosomes line up in the middles of the cells
Spindle fibers attach
Anaphase 2
Chromosomes pulled apart to opposite sides of the cells

18. Stages of Mitosis Telophase - 2
The separated chromosomes arrive at opposite ends of the cells
The nucleus begins to reform around the chromosomes
Chromosomes become less condensed.
Creates 4 gametes – cells with ½ the DNA of the original cell
Gametes = sex cells, also called sperm and eggs

19. Types of Reproduction
There are 2 mains types of reproduction that living things can use to reproduce
Asexual Reproduction
Offspring (child) has same DNA as the parent
Sexual Reproduction
Offspring has a mix of DNA from both the mother and the father.

20. Asexual Reproduction New organism is produced with DNA from 1 parent
Done through Binary Fission or Mitosis

21. Types of Asexual Reproduction
Bacteria
Use Binary Fission
Single Eukaryotic Cells
Use Mitosis
Plants
New plant starts from old plants leaves, roots, or stems
Example – Starting a bamboo plant from a leaf
Uses Mitosis
Animals
Called Budding
New living grows off the parent like a ‘bud.’ Eventually develops into a mature, independent living thing.

22. Sexual Reproduction New living thing produced using DNA from 2 parents
Only in Eukaryotic living things
Combines sex cells to make new living thing
New living thing has half DNA from mother, half DNA from father
When sperm and egg combine, it is called Fertilization
New formed cell is called a zygote

23. Types of Sexual Reproduction
External Fertilization
Egg and sperm combine outside of mother’s body
New living things develops outside of body in an egg
Examples – fish, coral, octopi, squid, etc. use this method.
Most animals that live in water use this method of fertilization

24. Types of Reproduction Internal Fertilization
Egg and sperm combine inside mother’s body
New living thing sometimes develops inside mother
Example – humans, mammals
Mother sometimes will lay egg.
Example – chicken, reptiles,
Most land animals use internal fertilization

25. Questions
A human embryo (developing baby) starts as one cell. It divides to grow. Would it use binary fission, mitosis, or meiosis?
An E.coli bacteria is dividing. What process would it use?
A jellyfish can make an exact copy of itself by budding off copies instead of using sexual reproduction. Would a jellyfish need to undergo meiosis? Explain why or why not. (3 marks)
What are the differences between mitosis and meiosis?
Create an expression to help you remember the phases of Mitosis.
Example of an expression – remember the order of the planets by saying: My Very Educated Mother Just Saw Uncle Nick 

26. Questions
What are the differences between sexual and asexual reproduction?
What are the similarities between sexual and asexual reproduction?
A trembling aspen is reproducing using asexual reproduction. What differences would there be between its DNA and its offspring’s DNA? Explain.
Which would create more genetic diversity (differences in the offspring's genetic material) amongst species? Asexual or sexual reproduction? Explain.