Download Unit VI: Cell Growth and Division

Unit VI: Cell Growth and Division
Making more cells, making sex
cells, and the problems that can
occur
A. Limits to Cell Growth
Organisms grow because they __________________
The elephant is
larger because it
has more cells
1. The larger the cell the ________________________
DNA ____________ cell activities
In large cells  unable to keep up with the need of
information
2. The larger the cell the ________________________________________
The exchange of materials depends upon _________________
The rate at which nutrients are used up and wastes are made depends
upon the cells volume (what is happening inside)
_____________________________
B. Cell Division
_____________________
Reduces volume
increase ratio of surface area: volume
1. Chromosomes
made of ________  carry genetic information
human cells – 46 chromosomes in 23 pairs
___________________ _________________
usually chromosomes are in the form of chromatin
during cell division chromatin condenses and becomes
visible chromosomes
2 identical sister chromatids
connected with a centromere
2. The Cell Cycle
The cell grows, prepares for division, and divides into
daughter cells
3. Mitosis
4. Meiosis
There are two different types of cell divisions for two different
purposes
Mitosis and Meiosis are very similar processes but with some
major differences
Mitosis is used for ________________________________
the organism. In some organisms it is used for ___________
__________________
Meiosis is only used to ______________________ (sex cells)
used in the process of __________________
Mitosis
Prophase
Meiosis
Prophase I
- _____________ condenses
into _____________ (become
visible)
- centrioles separate and move
to opposite sides of the cell
- centrioles form ____________
*in plants – no centrioles,
spindle forms from ________ in
the cytoplasm
- nuclear membrane __________
_____
____________
= pairing of
homologous
chromosomes
chromosome + copy
+ homologous +
copy
total of 4
chromosomes =
____________
Mitosis
Meiosis
Metaphase I
Metaphase
- chromosomes
attach to spindle
at their
______________
- chromosomes line up in
the _________________
- Tetrads line up
in the middle
- _______________
= homologous
chromosomes
switch pieces
“new combinations
of alleles” 
___________
Mitosis
Meiosis
Anaphase I
Anaphase
- ___________________
- Chromosomes separate
- _________________
apart – migrate towards
the centrioles
- in late anaphase
______________ starts
_____________ =
tetrads separate
and migrate to
opposite sides
of the cell
Mitosis
Meiosis
Telophase I
Telophase
2 new _________
___________
daughter cells are
formed
Mitosis is done
Restarts the cell
cycle
- chromosomes gather
at opposite ends of the
cell (poles)
- chromosomes unravel
- nuclear membrane
reforms
- ___________ finishes
Daughter cells
are __________
___________t
Cells take a brief
rest and then start
the next division
*remember
mitosis is done
This is the 2nd
division of
meiosis
Meiosis
Prophase II
- The process starts again but with ____________
- ________________________
- Chromosomes condense and become visible,
nuclear membrane disappears, centrioles migrate,
and spindle starts to form
*remember
mitosis is done
This is the 2nd
division of
meiosis
Meiosis
Metaphase II
- Chromosomes line up in the middle
- __________________________
- Centromeres replicate so chromatids can separate
*remember
mitosis is done
This is the 2nd
division of
meiosis
Meiosis
Anaphase II
- Chromatids separate and migrate
Single pieces – not homologous pairs
- Cytokinesis starts to separate the cytoplasm
*remember
mitosis is done
Meiosis
Telophase II
This is the 2nd
division of
- Nuclear membrane reforms
meiosis
- ___________________________ 1 Cell  4 cells
- Each has ___________________________ as the original
parent cell
- _______  _______
________  __________
- The distribution of homologous chromosomes is _________ 
thus _______________ frequently occurs
5. Comparing Mitosis and Meiosis
Mitosis
Type of Cells
# of Daughter
Cells
Chromosome #
# of Divisions
Homologous Pairing
Crossing Over
Compare DNA
Type of
Reproduction
Mitosis vs Meiosis
Meiosis
C. Uncontrolled Cell Growth
________________ = cells lose ability to control mitosis
Form masses of cells = _________________
__________________ = cancer cells break loose and
spread inside the body
Genetic and Environmental Links
D. ______________
Humans are created from 1 single
fertilized cell
Every cell in the body has the ______
____________________________
Cells ______________ and become
all types of cells
Specialized cells only use certain
_____________________
Once cells are specialized they can’t
go back
Stem cells are cells that can become
all different cells
Stem cells come from embryos? ? ?
E. Gamete Formation
_____________ = sex cell
Sex cell = ____________
and ___________ (in
plants pollen and ovum)
Happens by ___________
 reduces the number
of chromosomes so
offspring don’t have extra
chromosomes
• Mitosis Meiosis Questions
1. How does the number of daughter cells produced from
mitosis and meiosis differ?
2. How does the ploidy of the daughter cells produced from
mitosis and meiosis differ?
3. Do the daughter cells produced from mitosis contain
identical genetic complements?
4. Do any of the daughter cells produced from meiosis contain
identical genetic complements?
5. When do the homologous chromosomes separate during
mitosis?
6. When do the homologous chromosomes separate during
meiosis?
7. When do sister chromatids separate during mitosis?
8. When do sister chromatids separate during meiosis?