Cell Division Notes
A. Organization of DNA & Mitosis
I.
Why do cells divide?
Multicellular
Unicellular/Prokaryotes
1.
1.
2.
2. Binary Fission-
3.
4.
** Mitosis only in Eukaryotes
II. Problem of Cell Growth
o Larger cell =
o Limits to Cell Size:
1.

Too much for DNA to control- needs to be manageable

Cell needs to be small enough to move nutrients
2.
through efficiently
o RESULT:
III. Genetic Material

Different forms of DNA throughout cell cycle
Long _________________ threads
Chromatin
Form DNA is found in during _____________ of cell cycle
(interphase)
Chromatin _______________________
Chromosomes
Now visible under a microscope

Seen only during cell division
DRAW IT
Sister
Chromatids
___________________ copies of chromosomes
Created during ________________________
Connected by the ______________________
Chromatids
_________ copy of the chromosome
How many chromosomes are in cells?
Body (Somatic) Cellsmuscle/liver/brain etc.
Sex Cells (Eggs & sperm)
Red Blood Cells
Why?
** _________________________________- profile showing number &
appearance of chromosomes
B. Cell Cycle
Label the cell cycle
The Cell Cycle is:
2 Primary Phases of Cell Division:
1. Interphase (Growth)
2. M- Phase (Division)
Two Sub-phases:
A.
Period of cell ___________________.
Longest stage
Division of the _______________________
DNA = ____________________
DNA= ________________________________
Divided into 3 phases
B.
Division of the _____________________
DNA returns to ____________________
3 Sub- Phases of Interphase
1.
- Normal _______________ &
activities
- ________________ sub-phase
- __________________ cells
parts
2.
•
3.
DNA _____________________ - Final chance to grow
•
DNA is copied
producing the second
_____________________
G1 CheckPoint:
No Checkpoint!
•
- Checks for a ____________
for cells or _______________
DNA
- If no need, moves into G0
G2 Checkpoint:
Checkpoints ensure all
processes are working
smoothly and the cell is
ready for the next step.
Is the DNA fully
replicated?
•
Is there proper
growth/
____________________?
BEFORE MITOSIS
INTERPHASE
Description:
 Chromatin is not _______________ or ______________ with
a microscope
 Cell is in G1, S and G2
 ________________________ present- pair of centrioles to
guide movement of DNA during division
STAGES OF MITOSIS
PROPHASE
Description:
 Chromatin _______________ and forms ________________
 Centrioles ______________ and form _________________
 Nuclear membrane & nucleus begin to ___________
_____________
METAPHASE
Description:
 Chromosomes line up in the ___________________ of the
cell (at the metaphase plate)
 Chromosomes connected to ___________ fiber at
________________
ANAPHASE
Description:
 Sister chromatids ________________ and move to
________________ sides of the cell
 DNA now considered single daughter
chromosomes
TELOPHASE
Description:
 Chromosomes reach _______________ ends of cell
 Chromosomes ____________ to form ______________
chromatin again
 Two _________________ ____________________ form
 Spindle disappears
AFTER MITOSIS
CYTOKINESIS
Description:
 Cytoplasm pinches in __________
o Animalso Plants Cell membrane divides
 Each daughter cell has identical set of
__________________
Cell Cycle Regulation and Cancer
C. Stem Cells
•
Stem Cells are:
____________________________
cells (cells that do not have a
specialized function yet).
•
Stem cells eventually
_____________________ and
become nerve cells, skin cells, etc.
•
Important for Future Medicine

Can be used to regenerate
damaged tissue
D. How often do cells divide?
•
Certain cells divide frequently; others not at all once full mature


NEVER divide once mature- ____________ and ______________cells
•
These types of cells have very specific placements in the brain/muscles.
Taking one out to divide will ruin the function of the organ (like removing
a section of a train track).
•
They also have a very specialized structure- cannot go back to normal cell
structure after differentiating
Divide often- skin cells, digestive cells
HOW DO WE CONTROL CELL DIVISION?
E. Controls on Cell Division
•
Most cells in the body are not actively ___________________

•
Most are in _____________________
There are check points that cells must pass – Certain proteins control cell division
1. Internal Regulators (inside cell)
A. _________________ - class of proteins that regulate the stages of the cell cycle
B. ______ – protein that binds to cyclins to prevent excessive of cell growth until the
cell is ready to divide
C. p53

________________ suppressor protein

“Guardian of cells” – prevents ___________________ in DNA
o Activates DNA repair proteins to repair DNA before S phase occurs
o If damage is irreparable, cell undergoes _____________________ (cell
death)
2. External Regulators (outside cell)
•
Cell growth may occur when:

A new organism is _________________________

Cells have died due to injury or ________________ (signaled cell death)

Neighboring cells ______________for more cells

Ex:
3. Contact Inhibition
•
Normal cells: Cells
form a ________________
layer (1 cell thick)
•
Stop dividing when
__________________ one
another
•
Cancer cells:
D. Cancer Cells
•
•
Have a bigger ______________
•
_____________________ shape
•
Divide ______________________________
•
Have multiple _____________________________
•
Terms to know:
•
________________________________: Cancer cells are able to recruit and form new
blood vessels to get added nutrients for growth
•
________________________________: When cancer spreads to other parts of the body
1. What Causes Cancer
A. _____________________________ – cancer causing agents
Tobacco Use
Diet
Exposure to ______________________
Exposure to _________________
Inherited gene defects in tumor
suppressor genes (p53 & Rb)
Viruses
B. Immune system _________________
C. Telomeres (ends of chromosomes)
Treatments
Side Effects
 Only some types of cancer can be
treated this way
 May not get all cells
 Damages ______________________.
Surgery
Physically remove ________________
Radiation Therapy
Destroys cancer cell’s ability to
reproduce by damaging _____________
with radiation.
Chemotherapy
 Can injure or kill healthy cells,
especially those that
_____________________ frequently –
skin and blood cells
 Similar to radiation therapy
- Uses specific chemicals
- Often given two or more at a time to
_______________ cancer cells
Hormone Therapy
Blocks ________________________ that cancer
needs to grow
Biological Therapy
 Weakening of the bones can also
affect sex characteristics

Elicits a response from your
__________________ system (helps immune
system fight cancerous cells)
Allergic reactions, swelling,
itching also flu like symptoms,
greatest concern is extreme
allergic reactions
** In the cells below, draw the DNA as it moves through mitosis (assume before S
phase),
Cell Division Practice
Identify the phases of mitosis Interphase, Prophase, Metaphase, Anaphase, Telophase)
Write the phase on the line below and explain your answer.
1._________________________
2. ________________________ 3._____________________________
6. ________________________
5.________________________
Label the cell cycle with the word bank below:
Interphase
Prophase
Telophase
M-phase
G1
S
Metaphase
Anaphase
THE CELL CYCLE WORKSHEET
Matching: match the term to the description
G2
A. Prophase
B. Interphase
C. Metaphase
_____ 1. The sister chromatids are moving apart.
_____ 2. The nucleolus begins to fade from view.
_____ 3. A new nuclear membrane is forming around
the chromosomes.
_____ 4. The cytoplasm of the cell is being divided.
_____ 5. The chromosomes become invisible.
_____ 6. The chromosomes are located at the equator
of the cell.
_____ 7. The nuclear membrane begins to fade from
view.
_____ 8. The division (cleavage) furrow appears.
_____ 9. The chromosomes move to the poles.
D. Telophase
E. Cytokinesis F. Anaphase
_____ 10. Chromatids line up along the equator.
_____ 11. The spindle is formed.
_____ 12. Chromosomes are not visible.
_____ 13. Cytokinesis is completed.
_____ 14. The cell plate is completed.
_____ 15. Chromosomes are replicated.
_____ 16. The reverse of prophase (chomosomes
unwind).
_____ 17. The stage where chromosomes organize in
the middle.
Fill in the blank: Some will be used more than once.
A. Prophase
B. Interphase
D. Metaphase
E. Anaphase
C. Telophase
F. Centromere
G. Chromatid
H. Cytokinesis
I. Mitosis
J. Spindle fiber
K. Cell plate
________________18. What phase are daughter cells in as a result of mitosis?
________________19. During what phase of mitosis do centromeres divide and the chromosomes move
toward their respective poles?
________________20. What is the phase where chromatin condenses to form chromosomes?
________________21. What is the name of the structure that connects the two chromatids?
________________22. In a chromosome pair connected by a centromere, what is each individual chromosome
called?
________________23. What are the two parts of cell division?
________________24. What structure forms in prophase along which the chromosomes?
________________25. Which phase of mitosis is the last phase that chromatids are together?
________________26. Which phase of the cell cycle is characterized by a non-dividing cell?
________________27. What structure is produced from centrioles?
________________28. What forms across the center of a cell near the end of telophase – in a plant cell?
________________29. The period of cell growth and development between mitotic divisions?
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________________30. What is the phase of mitosis that overlaps with cytokinesis
The diagram below shows cells in various phases of the cell cycle. Note
the cells are not arranged in the order in which the cell cycle occurs.
Use the diagram to answer questions 1-7.
____________ 1. Cells A & F show an early and a late stage of the same
phase of the cell cycle. What phase is it?
____________ 2. Which cell is in metaphase?
____________ 3. Which cell is in the first phase of M phase (mitosis)?
____________ 4. In cell A, what structure is labeled X?
____________ 5. List the diagrams in order from first to last in the cell
cycle.
____________ 6. Are the cells depicted plant or animal cells?
a. Explain your answer.
b. If it were the other type of cell what would be different in
the diagrams?
____________ 7. What is the name of the longest phase of the cell cycle?
Which picture is it?
8. Why is mitosis important?
9. Predict what would happen if an individual had faulty spindle fibers.
10. Predict what would happen if cytokinesis was skipped.
Draw and label the following structure for each phase of mitosis:
Chromatin/Chromosomes (depends on phase)
Nuclear membrane
13
Centrosome/Centrioles
Spindle fibers
Interphase-
Prophase
Metaphase
Anaphase
Telophase
Final Result
What happens in the following sub-phases of Interphase?
G1:
S:
G2:
Homeostasis
- maintaining a constant internal environment
13
-
Maintains the environment through ________________.
-
Two Types of Feedback
Positive
•
Leads to change in the ___________
Negative
•
direction
direction
•
Causes the change to _____________
Leads to change in the ______________
•
and continue
Causes the change to ________ and return
to ________________
-
___________________ - change that sets off receptor
-
____________________- Senses change and produces a response
Homeostasis Webquest
-
Use the videos found IN MY SHARE DRIVE to fill in the blanks.
Wait for my signal to move onto the next station.
I. Thermoregulation- Regulation of HEAT- Video
A. Sweating
1. When do we sweat?
2. Sweat is released from the ___________ ______________ to cool down our body
temperature using _____________________ to remove excess heat through water
molecules
B. Shivering
1. When do we shiver?
2. Shivers _____________ our skin and make our muscle groups _____________, releasing
energy and ______________.
3. Goosebumps form because the muscles __________ and pull the hair taut.
II. Osmoregulation- REGULATION OF WATER
A. Contractile Vacuole: - Video
1. Protists such as the ____________________ have contractile vacuoles.
2. Contractile vacuoles fill with _________ by ____________ when the organism is placed
in a hypotonic solution causing to _______________ greatly.
3. The purpose of a contractile vacuole is to ____________ and ___________ water
through a pore in the plasms membrane.
13
B. Kidneys - Video (Stop at 3 minute mark)
1. Function of kidneys
a. Balance the amount of ___________ in body
b. Dispose of _____________ products and create ___________
c. Primarily filtration systems of the blood
d. Excess Water levels: Sends water to _______________ to be removed
e. Low Water Levels: Release __________ back into bloodstream
-
We also get thirsty (dry mouth) to stimulate drinking
C. Plants Are Special- Video #1 -- Osmoregulation
1. Plants have tiny openings in their leaves called ____________.
2. Each stomata is made of specialized cells called _____________ cells.
3. Stomata allow for water loss (or movement)– also called _________________
4. Plants open and close the guard cells to regulate water loss.
Video #2  Regulation of Breathing
1.
2.
3.
4.
Stomata allow them to “breathe”
Take in ______________ for photosynthesis
Can be closed to lessen water loss
Releases ______________ and ______________ through the stomata
III. O2/CO2 Intake (Breathing): Video Start at 1:15- 2:40  To show you gas exchange.
1. Where does gas exchange take place in the lungs?
2. When you breathe in, ______ fills your lungs and your capillaries are full of ________.
Video #2 (1:00-3:00)
3. When you breathe in, ____________ gets absorbed by capillaries and
________________ is given off into the lungs through the process of DIFFUSION.
4. Oxygen is carried all around the ______________ with red blood cells.
5. Breathing is controlled by what organ?
6. Increased breathing is due to a need for more _______________ for the working muscles.
7. This causes an increase in _____________.
8. The brain monitors the ________ concentration. If the ________ concentration is high,
then brain signals the ____________ to contract at a faster rate.
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IV. Blood Glucose: Video
A. Insulin and glucagon
1. Insulin (hormone made by the pancreas) helps to _____________ blood glucose concentration by
removing the glucose and stores it as ________________ in body cells.
2. Glucagon (hormone made by pancreas) helps to ________________ blood glucose concentration
by converting the stored glycogen back into ______________.
Video #2 (0-1:15)
3. When we eat carbohydrates, it supplies our bloodstream with GLUCOSE – needed for cell
energy.
4. Our glucose levels need to be within a certain ______________ in order to function properly.
5. _____________ glycemia – when blood glucose levels are higher than normal (MORE
GLUCOSE)
6. _____________ glycemia – when blood glucose levels are higher than normal (LESS
GLUCOSE)