Cell Cycle
and
Cell Division
BIG PICTURE
Mitosis
2n
2n
2n
One (Diploid) Cell becomes Two (Diploid) Cells
Example : Cats
Somatic Cells have 38 (2n) chromosomes
Sex cells have 19 (n) chromosomes
Chromosomes
• Contain the genetic information
• How this information is transmitted from one cell to
another
DNA Replication
Centromere
Arm
2 sister
chromatids
Genes/
DNA
Chromosome
(unduplicated)
Chromosome
(duplicated)
A Chromosome
Number of Chromosomes
Types of Chromosomes (Humans)
1. Body (Autosomes) – 44
chromosomes (22 pairs)
2. Sex – 2 chromosomes (1 pair)
(females XX, males XY)
Total Number of Chromosomes = 46
The End Result
Two cells are created with the same genetic
information and number of chromosomes
as their parent cell.
• http://www.johnkyrk.com/mitosis.html - *
• http://www.unitedstreaming.com/search/as
setDetail.cfm?guidAssetID=9B385B50541B-447A-89CF-2016A3CFC094
Where does Mitosis occur?
• Only occurs in somatic cells (ex. muscle,
skin)
• Produces diploid somatic cells
Interphase
During Interphase:
• Growth -> Duplication of
chromosomes -> Growth
• Takes in nutrients to build
proteins
• Duplicates chromosomes
within the nucleus to create
sister chromatids (joined by the
centromere)
Homologous Pairs
Prophase
• Individual chromosomes shorten and
thicken
• Strengthens DNA for Mitosis
Metaphase
• Sister chromatids line up along the middle
of the cell
Anaphase
• The sister chromatids split to form two
individual chromosomes
• The two individual chromosomes move to
opposite ends of the cell
Telophase
• Chromosomes reach the ends of the cell
• Nuclear membrane begins forming
• Cytokinesis occurs resulting in two
daughter cells each containing all cell
organelles and 2n chromosomes
• Interphase begins again
Telophase
Cell Cycle and Mitosis
• https://www.youtube.com/watch?v=C6hn3
sA0ip0
Make A Chart
• List IPMAT down the left side (below each
phase list how to remember it!)
• Across the top, put:
– Genetic Information (What form is it in?)
– Centrioles
– Spindle Fibres
– Nuclear membrane
– Drawing (place a rough labelled sketch in
here)
– Description of what is happening
• Describe how each of the cell parts
involved are behaving in each stage
Cell Cycle
Two main phases:
1. Interphase
3 stages
•
•
•
G1 – rapid growth
S – DNA replication
G2 – prepare for mitosis
2. Mitosis (M) = division of the nucleus
4 stages
•
•
•
•
Prophase
Metaphase
Anaphase
Telophase
3. Cytokinesis = Division of the cytoplasm
Mitosis
Interphase
Cytokinesis
Telophase
Prophase
Anaphase
Metaphase
Interphase
•
•
•
Growth
DNA replication
At the end, all chromosome have two sister
chromatids
Prophase
1. Chromosome formation
• DNA condenses
• Nuclear membrane dissolves
2. Centrioles move to opposite poles of cell
Metaphase
1. Centromere of chromosomes joins to spindle
fiber
2. Chromosomes line up in the middle of the cell
Anaphase
1. Centromere doubles
2. Chromatids separate and are pulled to
opposite poles by the spindle fibers
Telophase
1. Nuclear membrane reappears in the two
daughter cells
Cytokinesis – separation of cytoplasm;
final stage of cell division
Mitosis under the microscope
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
Mitosis Lab –Root Tip
Telophase
Prophase
Anaphase
Metaphase
Interphase
Vocabulary
The Cell Cycle
Chromosomes
Interphase
Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Mitosis On the Table
• Using pipe cleaners and your text,
recreate the stages of mitosis on your
desk with a partner
• 1 partner tries each phase, and the other
partner checks to make sure it’s done
correctly
• Raise your hand for teacher to check
• Then switch roles