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Unit 4 – Cellular Reproduction
Mitosis Notes
Name:
Number:
Objectives:
1.
2.
3.
4.
Cell Size Limitations
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
Surface area and volume limit cell size (SA:V ratio)
o __________________ increases faster than ____________________.
o Need large SA (cell membrane) relative to V (cytoplasm).
Maintain ________________________________ as cells grow.
Cell division solves the size problem.
Why do cells need to divide?
1. ______________________________________
 Humans need to replace old, worn out cells from normal wear and tear.
2. ______________________________________
 The cell membrane allows nutrients (glucose, oxygen, etc.) in and wastes out.
 Diffusion is fast over short distances, but slow over long distances.
 Cells can’t be giants, they would starve to death or be poisoned from the build up of wastes.
3. ______________________________________
 Need a proper SA:V ratio to support the needs of the cell (large SA relative to volume).
 The volume increases faster than the surface area of the cell membrane.
 Larger cells need more “stuff” but only so much can cross the cell membrane at a time.
4. ______________________________________
 Since DNA codes for making protein there needs to be enough to support the protein needs of the cell.
 The cell membrane has a lot of proteins and if the cell size increases than you would need more protein.
Prokaryotic vs. Eukaryotic Cell Division
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Prokaryotic cells are ______________________ & ______________________ than eukaryotic cells.
Eukaryotic cells take much longer to prepare for cell division.
Eukaryotic cells have to copy more ___________________and build new ______________________.
How long does it take eukaryotic cells to divide? ______________________
Unit 4 – Cellular Reproduction
Mitosis Notes
Cell Division
____________________________ - Division of the nucleus
____________________________ - Division of the cytoplasm
The Cell Cycle
Interphase:
“In between phase”
a) G1 phase – cell grows rapidly and carries out its routine functions
b) G0 phase – cell is neither dividing nor preparing to divide
b) S phase – DNA (chromosomes) is copied
c) G2 phase – cell continues to grow
- organelles are copied
- final preparations for cell division
M Phase:
-
Cell division takes place
Nucleus divides first (mitosis)
Cytoplasm divides second (cytokinesis)
A. ___________________________
“In between phase”
a) G1 phase – cell grows rapidly and carries out its routine
functions
b) G0 phase – cell is neither dividing nor preparing to divide
b) S phase – DNA (chromosomes) is copied
c) G2 phase – cell continues to grow
- organelles are copied
- final preparations for cell division
A.
B. Phases of Mitosis (M phase) – 4 stages
1.) ___________________________
“Preparation phase”
a.) Chromosomes condense and shorten
b.) Chromatids attached near center by
centromere
c.) Centrioles separate, migrate to the
poles
d.) Spindle fibers form between centrioles
e.) Nuclear membrane disintegrates,
nucleolus
disappears
Unit 4 – Cellular Reproduction
Mitosis Notes
1.
2.) ___________________________
“Middle phase”
a.) chromosomes line up in pairs at the
center of cell
b.) centromere of each chromosome is
attached to a separate spindle fiber
2.
3.) ___________________________
“Apart phase”
a.) Centromere of each chromosome separates
b.) Separation of the chromatids in each pair
c.) Spindle fibers appear to shorten, pulling the
chromatids apart at the centromere
(now called chromosomes)
d.) migration of the chromosomes ends with the
arrival at the poles and the formation of
clusters
3.
4.) ___________________________
“Two cell phase”
a.) Cleavage furrow forms b/w 2 cells &
spindle fibers disappear
b.) Nuclear membrane forms around each set of
chromosomes (forms 2 new nucleus)
c.) Chromosomes uncoil to form chromatin net
(getting ready for interphase)
d.) Nucleoli reorganized
C. ___________________________ - division of the cytoplasm
- In animal cells - cell membrane pinches together,
furrow forms along the equator.
4.
Unit 4 – Cellular Reproduction
Mitosis Notes
- In plant cells - cell plate forms in the middle of the
dividing cell.
C.