1. Cell Division:
Asexual Reproduction

2. Interphase Mitosis Cytokinesis Asexual Binary Fission
OUTCOME QUESTION(S):
S1-1-01:
Why do cells divide and how does it work?
Vocabulary & Concepts 
Interphase Mitosis Cytokinesis
Asexual Binary Fission

3. Why do cells divide and how does it work?
All “new” cells (growth, repair or reproduction) are produced from “old” cells – every cell is either dividing, or preparing to divide…
Why do cells divide and how does it work?

4. Interphase
Longest phase
Living life and preparing for eventual division
Chromosomes (46 books) must be copied

5. Mitosis is how all new somatic (body) cells are made
Division phase - consists of two parts:
1. Mitosis - division of chromosomes and nucleus.
Giving both cells a complete set of “books”
Mitosis is how all new somatic (body) cells are made
2. Cytokinesis - dividing cytoplasm and organelles.
End Result:
Two identical cells that re-enter interphase begin the process again.

6. Chromosomes look like spaghetti - uncondensed
There is obviously a lot more going on in the cell…but we are just focused on what the chromosomes are doing during interphase and mitosis
Chromosomes look like spaghetti - uncondensed
Chromosomes copied, cell grows and makes more organelles (preparing to divide)

7. Chromosomes become visible – condense
Centrioles
Sister
Chromatids
Chromosomes become visible – condense
Copied chromosomes pair up – look like an “X”
The condensed copied chromosomes – called sister chromatids – are joined at the middle which is why they have the “X”-shape

8. Chromosomes are guided into the middle by attached spindle fibres
Sister Chromatids
Copied chromosomes (sister chromatids) line-up along the middle of the cell
Chromosomes are guided into the middle by attached spindle fibres

9. Sister chromatids
separated
Copied chromosomes (sister chromatids) pulled apart towards opposite ends of cell
This is done by the spindle fibres “shortening” and pulling them inwards

10. Chromosomes back to spaghetti - uncondensed
Cleavage of
cell into two
Chromosomes back to spaghetti - uncondensed
A new nucleus forms around each set of chromosomes

11. Leaving 2 identical daughter cells
Cytokinesis
Cell membrane grows inwards - pinching into 2
Each daughter cell has a complete set of the chromosomes – plus organelles and cytoplasm
Leaving 2 identical daughter cells

12. Identical daughter cells
Interphase
Prophase
Metaphase
Parent cell
Copied and condensed
Lining up
Anaphase
Telophase
Cytokinesis
Pulling apart
Nucleus forming
Identical daughter cells
MITOSIS

13. Full set of Chromosomes Full set of Chromosomes
MITOSIS – in general P M A T
Parent cell:
Full set of Chromosomes
This is the general structure that you will have to understand occurs for all 46 chromosomes
Daughter cells:
Full set of Chromosomes
2 identical daughter cells

14. Asexual and Sexual Why do cells divide? Reproduction
– Pass on genetic information
There are 2 types of organism reproduction:
Asexual and Sexual

15. Create offspring from one parent organism
Asexual Reproduction
Create offspring from one parent organism
Using basic cell division - Mitosis
Rapid and effective reproduction method
Cells are “clones” – genetically identical
Mitosis IS asexual reproduction: making an identical copy (offspring) from an existing cell (parent)

16. Binary Fission One example of Asexual Reproduction:
Simple single-cell (unicellular) organisms
Bacteria have 1 circular chromosome (plasmid)
Bacteria
(like E. Coli)
Remember: even though we call this “binary fission” it is still just a simplified Mitosis

17. Some other examples of Asexual Reproduction:
Fungi
(yeast)
Bacteria
Fungi
(mould)

18. Full set of Chromosomes Full set of Chromosomes
MITOSIS – in general P M A T
Parent cell:
Full set of Chromosomes
Remember:
ALL asexual methods of reproduction are just fancy Mitosis
Daughter cells:
Full set of Chromosomes
2 identical daughter cells

19. PROS – Asexual Reproduction – CONS
No diversity in organisms
clones are vulnerable to disease/environment
Large number of offspring
made very quickly
Each offspring will be successful
clones are well adapted
Little possibility for evolution
clones are identical
Stay close together
colonies build if nutrients are present
Can lead to overcrowding
starvation if not enough nutrients
No need to waste energy
finding a sexual partner ?

20. CAN YOU ANSWER THESE QUESTIONS? S1-1-01:
Why do cells divide and how does it work?
Vocabulary & Concepts 
Interphase Mitosis Cytokinesis
Asexual Binary Fission