1. Just as humans go through a life cycle, cells go through a cell cycle.
grow
reproduce
marriage
puberty

2. The cell cycle:
Chromosomes
Divide
Grow
DNA Replication
Daughter cells

3. Cell Cycle
Series of events cells go through as they grow, replicate their DNA, form chromosomes, and divide into two daughter cells. G R C D D

4. It is considered a cycle because each daughter cell starts the process over after division is complete. D D

5. Cell cycle diagram in SG:
Each section of the diagram represents a different event in the cell’s life
Circular diagram = cycle

6. GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

7. The cell cycle is divided into 2 main parts.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

8. This part of the cell cycle is all about division…
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

9. …and this part of the cell cycle is all about preparing for division.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

10. INTERPHASE M PHASE M = MITOSIS INTER = BETWEEN GROWTH DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

11. Interphase Part of the cell cycle when the cell prepares for division.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM
Part of the cell cycle when the cell prepares for division. C C P D

12. M Phase
NEW PAGE IN NOTES
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM
Part of the cell cycle when the cell divides (first the nucleus, then the cytoplasm.) C C D N C

13. Interphase is longer than M phase.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

14. This is because DNA replication occurs during interphase
This is because DNA replication occurs during interphase. Remember, the DNA molecule is extremely long, so it takes a long time to replicate… R

15. …and it must be replicated without making any mistakes.

16. How can you tell if a cell is in M phase or interphase?

17. Identifying Cells in the Cell Cycle
Interphase
(preparing)
Chromosomes
M phase
(dividing)

18. Since M phase cells are in the process of dividing, they have visible chromosomes.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

19. M phase cells: X X X X

20. Identifying Cells in the Cell Cycle
Interphase
(preparing)
Chromosomes
Fully-formed
M phase
(dividing)

21. Since interphase cells are not ready to divide, they do not contain chromosomes.
GROWTH
DNA LOOSENS
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES
DNA REPLICATION
CHROMOSOMES FORM

22. Interphase cells:

23. Identifying Cells in the Cell Cycle Fully-formed chromosomes
No chromosomes
Interphase
(preparing)
Fully-formed chromosomes
M phase
(dividing)

24. You’ll notice that most of these cells are in interphase, since interphase takes longer than M phase. L

25. Interphase is divided into 3 parts.
GROWTH
DNA LOOSENS G1
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM

26. During G1, the cell grows and makes new organelles.

27. INTERPHASE M PHASE G1 S G2 GROWTH DNA LOOSENS CYTOPLASM DIVIDES
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM

28. During S phase, the DNA is replicated by enzymes.

29. INTERPHASE M PHASE G1 S G2 GROWTH DNA LOOSENS CYTOPLASM DIVIDES
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM

30. What happens during G2?
DNA MOLECULE
REPLICATED DNA

31. During G2, the cell checks for any errors made during DNA replication and fixes them before chromosomes form. E R C

32. INTERPHASE M PHASE G1 S G2 GROWTH DNA LOOSENS CYTOPLASM DIVIDES
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM
CHECK FOR ERRORS

33. How can you tell if a cell is in G1, S, or G2 of interphase?

34. Identifying Cells in the Cell Cycle Fully-formed chromosomes
No chromosomes G1 S
Interphase
(preparing)
End of G2
Fully-formed chromosomes
M phase
(dividing)

35. What would G1 cells look like?
GROWTH
DNA LOOSENS G1
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM
CHECK FOR ERRORS

36. Identifying Cells in the Cell Cycle Fully-formed chromosomes
No chromosomes G1
Small (just divided) S
Interphase
(preparing)
End of G2
Fully-formed chromosomes
M phase
(dividing)

37. G1 cells:

38. What would S phase cells look like?
GROWTH
DNA LOOSENS G1
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM
CHECK FOR ERRORS

39. Identifying Cells in the Cell Cycle Fully-formed chromosomes
No chromosomes G1
Small (just divided) S
Fully-grown
Interphase
End of G2
Fully-formed chromosomes
M phase

40. S phase cells:

41. What would cells at the end of G2 look like?
GROWTH
DNA LOOSENS G1
CYTOPLASM DIVIDES
INTERPHASE
M PHASE
NUCLEUS DIVIDES S
DNA REPLICATION G2
CHROMOSOMES FORM
CHECK FOR ERRORS

42. Identifying Cells in the Cell Cycle Fully-formed chromosomes
No chromosomes G1
Small (just divided)
Fully-grown
Interphase S
End of G2
DNA starting to condense
Fully-formed chromosomes
M phase

43. End of G2 cells:

44. Which cells are in interphase? Why?
No chromosomes A B C D

45. Which cell is in M phase? Why?
Fully-formed chromosomes A B C D

46. Which cell is in S phase? Why?
Fully-grown A B C D

47. Which cell is in at the end of G2? Why?
DNA is starting to condense A B C D

48. Which cell is in G1? Why?
Small (just divided) A B C D