Cell cycle

1. Cell Cycle &
Mitosis
Grade 10
Biology
Farah Nasr

2. Lesson objectives
Define cell
cycle
1
Describe the
phases of
the cell cycle
2
Define
mitosis and
its stages
3
Explain the
importance
of cell cycle
4

3. Question :
How do
organisms
grow?
What
happens
when cells
become old
or damaged?

4. Cell cycle
• The cell cycle is the series of
events that enable cells to
• Grows
• Replicate its DNA
• And divides to form new cells
• It consists of two phases
interphase and mitotic phase

5. Interphase:
• G1 phase ( growth stage 1): cell
grows and synthesis new proteins
and orgenelles
• S phase ( synthesis
stage): chromosomes are replicated
and DNA synthesis take place
• G2 phase ( growth stage 2) : cell
prepare for division
• Interphase is the longest phase of
the cell cycle

6. Mitosis :
• The process where a single cell
divides resulting in two identical cells
, Each containing the same number
of chromosomes and same genetic
information
• It consists of four major stages

8. Prophase:
• Prophase is the first and longest
phase of mitosis
• The centrioles separate and take up
positions on opposite sides of the
nucleus
• Nuclear envelope disappear
• Chromosomes condense and sister
chromatids forms

9. Metaphase :
• The second phase of mitosis
• Chromosomes move to the equator of
spindle
• The center of the cell
• Each chromatid is attached to spindle
with centromere

10. Anaphase:
• Centromere split and sister
chromatids separate into opposite
poles of the cell
• Each chromatid is now a separate
chromosome
• The chromosomes continue to move
until they are separated into two
groups

11. Telophase:
• Nuclear envelopes reform
• Chromosomes begin to uncoil
and lose their distinct shape
• They gather to opposite ends of
the cell

12. Cytokinesis:
• Cytoplasm divides
• Two new daughter cells are now
separate
• Each daughter cell has an identical
set of duplicate chromosomes

13. Why is the cell
cycle important ?
• This process replaces damaged
cells
• It repairs and maintains the
health of the cells
• It also aid in the survival and
growth of biological organisms

14. What happen in case
of mitosis failure?
• It can lead to cell death
and to permanent cell
cycle arrest
• And mutation which is the
proliferation of abnormal
cells with incorrect
number of chromosomes

15. Exit ticket :
Fill in the Blanks
• DNA replication occurs during the ______ phase.
• Chromosomes line up at the equator during ______.
• The division of cytoplasm is called ______.
Statement:
“During telophase, chromosomes line up at the equator
and spindle fibers pull them apart.”
Task:
• Identify two errors in the statement and correct them.

16. Thank you