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CHAPTER 2, LESSON 3:
Cell Division
WHAT IS AN EXAMPLE
OF A CYCLE?
Water
cycle, life cycle, Moon
phases, months of the year,
daily tides, etc…
Cells go through a cycle,
known as the CELL CYCLEcells grow and divide.
3 FUNCTIONS OF CELL DIVISION:
1. Allows multicellular organism to grow larger
 A single cell divides into two, two into four, etc.
 In this way, a single cell becomes a multicellular
organism
3 FUNCTIONS OF CELL DIVISION:
2. To repair damaged, sick, or aging cells
 To heal a broken bone
 To heal a wound/cut
3 FUNCTIONS OF CELL DIVISION:
3. Reproduction
 Many single-celled
organisms (ex:
amoebas)
reproduce this
way.
 Cacti can grow
new stems & roots,
which then break
away from the
parent plant to
become a separate
plant
PG. 57- FIGURE 1
1.
2.
Label each photo as: Growth, repair, or
reproduction.
Which photo(s) represents more than one
function and what are they?
GROWTH
REPAIR
REPRODUCTION
GROWTH
A
seedling growing from a seed into a
new plant as a result of cell division
REPAIR
Damaged
skin is being
repaired or
replaced as a
result of cell
division
REPRODUCTION

Mother leopard
produces cubs through
reproduction, which
involves cell division.
The
cubs will
grow by cell
division
THE CELL CYCLE
 During the cell
cycle, a cell grows,
prepares for
division, and
divides into two
new “daughter
cells.”
 Each of the
daughter cells then
begins the cell cycle
again
THE CELL CYCLE
 Length of cell cycle
varies by cell.






Bean plants – 19 h
Animal embryo – under 20
min
Frog egg cells- 30 min
Yeast cells- 90 min
Fruit fly wing cell- 9-10 h
Human cells:
Avg. about 16 h
 Skin/bone cells
constantly repeat cycle
 Liver cells- over 1 yr

3 STAGES
1. Interphase
2. Mitosis
3. Cytokinesis
Use your graphic
organizer to take
notes on:
Interphase,
the 4 phases of Mitosis
& Cytokinesis
Textbook- pgs. 60-61
STAGE 1:
INTERPHASE




Cell grows- grows to full size, makes more chloroplasts,
ribosomes, mitochondria, and enzymes
DNA Replication: makes a copy of its chromosomes, now has
2 identical sets
Preparing for division- animal cells duplicate centrioles
Most of the life of a cell is spent in this period of cell growth
and development (interphase)
PLANT VS ANIMAL CELLS

Animal Cells have centrioles plant cells do not
STAGE 2: MITOSIS
During mitosis,
the cell’s nucleus
divides into 2 new
nuclei and 1 set of
DNA is distributed
into each
daughter cell.
Has 4 phases
PHASE 1: PROPHASE
 Chromosomes condense & are now visible
 Centrioles move to opposite ends of cell
 Spindle fibers form from centrioles
 Nuclear envelope breaks down
PHASE 2:
METAPHASE
 Each chromosome attaches to a spindle
fiber at its centromere
 Nucleus is gone
 Chromosomes have moved to the middle
PHASE 3: ANAPHASE
 Centromeres split, pulling chromatids apart
 Chromosomes
are pulled to opposite ends of cell
 The cell stretches out
PHASE 4: TELOPHASE
 Nuclei form
 Spindle fibers
disappear
 Cell is pinched in the
middle
STAGE 3 OF CELL CYCLE:
CYTOKINESIS
 Cell splits
into 2
daughter cells
 Each cell has an
identical set of
chromosomes & half
the parent cell’s
organelles
 In plant cells- cell
plate forms
CYTOKINESIS ANIMAL CELL

Cytoplasm pinches into two cells. Each daughter
cell has same number of chromosomes
CYTOKINESIS PLANT CELL
Cell does not pinch in the middle because of cell
wall
 Cell plate forms in the middle

TIME TO DRAW YOUR DIAGRAMS!
Textbook- pgs. 60-61
TIME
"Mitosis"
FOR
BRAINPOP!!!
CELL DIVISION PUZZLE
With your table, fix your puzzle so that the phases
of cell division are in the correct order and
matched up with their proper diagram and
description.