1. Biology Unit: Cells are derived from other cells
How are new cells formed?
Take answers on “why divide?”
Reproduce
Repair/replace
growth
Review: Living thing (made of cells, grow, consume, produce waste, react to environment, reproduce)
Cell Theory: cells is basic unit of life, All things made up of cells, cells come from cells,
How are new cells formed?
Why is it important for cells to reproduce?

2. Cell Growth and Reproduction
CHAPTER
Cell Growth and Reproduction 2
Key Ideas
The functions of cell division are growth, repair, and reproduction.
DNA in the nucleus plays a key role in normal cell functions and in cell division.
The cell cycle includes the normal cell functions and cell division.
Mutations in a cell’s DNA can cause diseases, including cancer.
Some organisms reproduce asexually through cell division.

3. Cell Growth and Reproduction
CHAPTER
Cell Growth and Reproduction 2
All organisms are composed of cells.
Some organisms are composed of only one cell (unicellular organisms). Example: bacteria
Some organisms are composed of two or more cells (multicellular organisms). Examples: corn plant flatworm (Planaria) sheep

4. Cell Growth and Reproduction
CHAPTER
Cell Growth and Reproduction 2
The cells of all organisms undergo cell division.
List as many reasons as you can for why cells divide.
Read pages 36 and 37 in your textbook.
Compare the reasons you gave for cell division with the reasons given in the reading.

5. Why do cells divide?
Growth - cells divide once they have grown large enough (volume cytoplasm : surface area of membrane ratio becomes too large for diffusion to be effective)
Eg. Cells grow and divide in multicellular organisms
Ted Ed video: largest single celled organism
murry-gans

6. Why do cells divide?
Repair/replace - old/dead/damaged cells are replaced through cell division
Eg. Bark cells divide to produce new bark tissue

7. Why do cells divide?
Reproduce – usually used by UNICELLULAR organisms to make NEW individuals
Eg bacteria divide to make two identical bacteria

8. Why Reproduce?
Reproduction ensures that life exists beyond its present generation
Reproduction transfers genetic information from parents to offspring.
What do species to do enhance chances of reproduction?
Flowers – scent and colour
Animals – colour, antlers, courtship ritual

9. The Importance of Cell Division
2.1
Cell division produces new cells to increase the size of the organism.
Cell division produces new cells to replace damaged and old cells.
Organisms use cell division in the process of reproduction.

10. Every species has its own strategies for reproduction
Flowers of many plants have colours and scent that attract animals so that they ca pick up and transfer pollen to other flowers

11. Every species has its own strategies for reproduction
Many animals have courtship rituals that enable sexually mature individuals of a species to become mating pairs.

12. Every species has its own strategies for reproduction
Microbes such as yeast and bacteria reproduce on their own and form offspring by dividing in two.

13. Two basic ways living things reproduce
Asexual Reproduction:
offspring come from a single parent
Each offspring receives a copy of the parent’s genetic material.
 Offspring are genetically identical to the parent and to each other.

14. Two basic ways living things reproduce
Sexual Reproduction:
offspring come from a two parents
Each offspring receives half of its genetic material from each parent.
 Offspring are NOT genetically identical to the parent nor (in most cases) each other.

15. What do you remember from grade 8?
Label the parts of the cell

16. What do you remember from grade 8?
What is the difference between a plant cell and an animal cell?
Do plant cells divide?
Do plants have chromosomes?
Cell wall, chloroplasts, large central vacuole

19. Cell Structures Involved in Cell Division
2.2
VOCABULARY
nuclear membrane
DNA (deoxyribonucleic acid)
nucleolus
centrioles
The nucleus contains the nucleolus and chromosomes.
DNA is contained in the chromosomes of each cell.
DNA contains the genetic information needed to direct all of a cell’s activities.
Microtubules in the cytoplasm allow movement of organelles within the cell and provide support for the cell.
Centrioles are made of special microtubules and are active during cell division in animal cells.