2. The Cell Cycle

3. Have you ever wondered…
How do we go from one single cell to a baby?

4. Take a look at these two animations…B A
Which one represents how our cells grow?

5. Lets imagine our world if we were only ONE CELL and we GREW by just GETTING LARGER

6. Ridiculous huh? What would be some disadvantages of this method of growth?

7.
We once started off as one cell and now our body is made up of trillions of cells.
While watching the video clip, answer the following…
How did we developed so many cells in our body?
What is the purpose of cell division?
What would happen if our cells didn’t divide?
Teachers: You can pause and ask the students what happens at each phase of the interphase after watching the video.
Stop at 4:27

8. 30 seconds Discuss with your neighbor…
How did we developed so many cells in our body?
What is the purpose of cell division?
What would happen if our cells didn’t divide?
By now, most of you should know that in order to make more cells our cells go through a process called cell division.
The students should come to the conclusion that the cell divides to make new cells. If cells don’t divide, new cells can’t be made to replace old cells; some don’t divide (brain and nerve cells).

9. Why do our cells need to divide?

10. PURPOSES OF CELL DIVISION
Growth- increase in size of the organism
Occurs by dividing cells, not by increasing the size of the individual cells

11. PURPOSES OF CELL DIVISION
Repair – needed because of worn out or injured cells
Your skin cells are replaced every 28 days
Your stomach every 7 days

12. PURPOSES OF CELL DIVISION 3. Reproduction (2 types)
Asexual – one parent. Offspring identical to parent – made through Mitosis
Sexual – combination of genetic material from two parents – made through Meiosis.
Offspring different to parents

13. So our cell…it works like a clock
At a certain time the cell “grows” and on the other times it divides.
I can ….describe the stages of the cell cycle, including deoxyribonucleic acid (DNA) replication and mitosis, and the importance of the cell cycle to the growth of organisms

14. Terms to know (Please write these on the next blank page in your journal.)
Chromosome: Structure found in the nucleus of eukaryotic cells that contain the organism’s genetic material; made of chromatin.

15. Chromatin: strands of DNA found in the nucleus; makes up chromosomes when folded and thickened around proteins.

16. Chromatid: one of two strands of a chromosome that become visible during mitosis or meiosis.

17. Centromere: the region of the chromosome that holds the two sister chromatids together.

18. Vocabulary
Mitosis – division of the nucleus. It is an asexual process since cells produced by mitosis are genetically identical to the parent cell
Cytokinesis - division of the cytoplasm

20. Let’s build a Chromosome………..
When you have your chromosome built, explain the structures & functions of each part and where you find chromosomes to your table group.

21. Bell-Ringer Glue the Cell Cycle Notes on your next blank page!
Grab ONE gluestick from the blue tub for your TABLE!!!

22. Cell Cycle (before cells divide)

23. Interphase The longest phase of cell cycle, cells prepare to divide
90% of the time cell is in interphase-
Includes: G1, S, G2, Go

24. G1 Phase (Growth Phase 1) “Cell being a cell”
Cell decides whether or not to divide
Growth and development, cell increase in size
Organelles are duplicated, proteins are made

25. S Phase: Synthesis/ DNA Replication
Chromosomes copied, 2 sets of complete DNA

26. G2 Phase (Growth Phase 2) DNA replication is checked and repaired
Cell prepares for mitosis (cell division), grows more
Proteins organize themselves into spindle fibers

27. G0 Phase (Resting, Time Out)
An extended G1, resting period
Some cells staying G0 temporarily when cell division is not required
Some cells will stay in G0 forever
Ex: Nerve cells & Heart Muscle cells

28. Mitosis Nuclear division Includes: Prophase Metaphase Anaphase
Telophase

29. Cytokinesis
Result in two Identical daughter cells

30. Which phase of interphase involves cell growth and development?
G1 phase
S phase
G2 phase
G0 phase

31. Which part of interphase involves DNA replication (making copies)?
G1 phase
S phase
G2 phase
G0 phase

32. Which phase of the cell cycle is the LONGEST phase?
Interphase
Mitosis
Cytokinesis

33. What happens to cells at G0 Phase?
Cells continue to grow
Cells stops dividing
Cells grow uncontrolled

34. Where is the longest phase of cell cycle?
Mitosis
Cytokinesis
Interphase

35. Check points-regulated by Cyclin Proteins

36. Lets take a look again at how bacteria grows….and how we grow

37. Bacteria growth: Binary Fission
A type of asexual reproduction that involves the splitting of cells into two. Occurs in Bacteria.
Cells makes copy of its DNA
Cell divides into two