Transcript The Cell Cycle - Siegel Science

The Cell Cycle
SEPUP Cell Biology: Activity 13
Brainstorming!!
 What do cells need energy for?
Transport/movement
Obtain food/energy
Produce building blocks of cells
Reproduce
Let’s Dance for CELL Division!! 
 Cell division is the basis of reproduction for all
organisms, and also for the development and
growth of multicellular organisms. The complete
sequence of phases from the end of one cell
division to the end of the next is called the cell
cycle. The cell cycle is divided into a sequence of
four phases.
 One of these four phases, called mitosis, is the
stage at which the cell divides to produce two
new—or offspring—cells.
REGULATORS… mount up! 
 A group of cell-cycle control proteins regulates the
phases of the cell cycle to ensure that all events needed
for normal cell division take place before division begins.
Cell-cycle regulation also ensures that specific
cell types divide at the right time and place. For
example, in the human body red blood cells must be
replaced about every 120 days. If the stem cells that
differentiate into red blood cells become under- or
over-active, either too few or too many red blood cells
are produced. Regulation of the cell cycle also ensures
that a cell completes the growth and synthesis phases
so that it will divide properly. When cell growth and
division proceed abnormally, cancer might result.
 A group of control proteins regulate the phases of
the cell cycle to ensure that normal cell division
take place. Cell-cycle regulation also ensures that
specific cell types divide at the right time and place.
 For example, human red blood cells must be
replaced about every 120 days. If the stem cells that
change into red blood cells become under- or overactive, the wrong number of red blood cells could
be produced.
 Regulators are also important because when cells
grow and divide abnormally, cancer might result.
It's Game Time!
In this activity we are going to be able to see
cell division happening in different types of cells:
Red blood cell
Liver cell
Nerve cell
Skin cell
To do this we will play the most spectacular
board game... The Cell Cycle!
Let's read the procedures for the game!
…Right now!
Read through the procedures (ON YOUR
OWN). Cross out Step # 14 and 15.
Pick ONE of the cells we will look at. What
would happen to the entire organism if that cell
could not reproduce? Why?
Let the Cell Cycle Begin!
Assemble with your group and begin playing
the game. Remember to record what cell you
are on your game sheet!
Move through the rounds quickly, but make
sure you are paying attention! Write down
EVERYTHING that happens to your cell.
During two “Thinking Breaks”, please write
briefly about what is happening to ALL the cells
in your group. This is after round #7 and #14
There are TWO sides to your game key! Use the
key to figure out what happens to your cell.
Take notes on your game sheet of what is
happening. It is VERY important to keep track of
this! For example, if you change CELL TYPE, write
it down!
You need to record what phase your cell started
in that round, where your cell ended up, and how
many cells you ended up with.
Use your plastic cup to hold cells that are created
but not dividing. Use your Play-doh container to
hold extra clay. You will use it to grow your cells.
If you turn into a cancer cell or change cell type
you will still use the same color clay.
Possible Game Key Scenarios
DESTRUCTION: If your cell was destroyed, you
start the next round with a NEW cell in G1 phase.
This is the SAME SIZE cell that you started with.
ROLL AGAIN: If you are told to roll again in the
same round, GO FOR IT and record EVERYTHING
that happened to your cell on your game sheet.
NEXT ROUND: If you are told to do something in
the next round, you have to remember what to do! In
the next round don’t roll, just do it!
SKIP A TURN: If you are told to SKIP a turn, but
are told what to do the round after that, you MUST
remember what to do!
Something to think about…
What are the different phases of the
cell cycle? Which was the shortest?
Longest?
Which cell seemed to divide the
most? Least? Why?
Did anyone become a cancer cell?
What happened?
Thinking Break #1
1. What has happened to your group’s cells
so far?
2. In what ways are your cells’ cycles the
same?
3. How are they different?
Thinking Break #2
1. What are the important events that happen
in each phase of the cell cycle?
2. What are the kinds of things that can go
wrong in each phase of the cycle?
Complete this Thinking Break with students
that started the game as the same cell type.
Also fill in the chart with information about
your cell. Use the game board to help you!
How were these cells different when it
came to the cell cycle?
Nerve cell
Liver cell
Skin cell
Blood cell
Liver Cell
 Divided occasionally
 Cells often stayed in Go
 Normal mitosis & cytokinesis produced two daughter cells
 Sometimes cycle did not work correctly resulting in a destroyed
cell.
 Sometimes that cell was not destroyed and became cancerous.
What does this mean?
 Cyclin accumulated.
Nerve Cell
Nada nothing….
Why is damage to nerve cells
permanent?
Skin & Blood Cell
 Cells grew and divided frequently.
 Normal mitosis & cytokinesis produced two daughter
cells
 Sometimes cycle did not work correctly resulting in a
destroyed cell.
 Sometimes that cell was not destroyed and became
cancerous.
 Cyclin accumulated.
Cancer Cell
Cell with a previous “life” that divided
without controls.
Some of these cells were destroyed
(did not happen in our class).
What happened?
Players that started as the same type of cell
will get together and discuss what happened to
their cell. They should notice some similarities
and write them down in the chart.
Groups will get back together and help their
team members fill in the rest of the chart by
sharing what they found out about their
particular cell.
Similar cells from stations 1-5 will meet on
ONE side of the room while cells from stations
7-11 will meet on the OTHER side of the room!
Analysis Questions!
 1. Of the cell types you investigated, which
divide:
a. frequently? Red blood cell, skin cell
b. occasionally, as needed? Liver cell
c. never, or almost never? Nerve cell
d. more frequently than normal and without
control? Cancer cell
 2. What kinds of factors regulate a cell’s
progress through the cell cycle?
Proteins!
 3. Beginning with G1, list the four phases of the
cell cycle in order, and describe what happens in
each phase.
G1 – cell growth
S - DNA replication
G2 – cell growth & prepare to divide
M - cell division
 4. Why is it important for each of the following to
be regulated?
a. Entry into the cell cycle
• A cell must be able to divide when the body needs
it to. If it is not triggered to enter the cell cycle
there might not be enough cells.
a. Progress from one phase of the cell cycle to the
next
• Every step is important! If a cell leaves one phase
too early it might not be large enough to divide or
it might not have all of its DNA properly copied.
 5. A cell in the liver divides. Its offspring and all
of their offspring continue to divide as fast as
they grow and synthesize DNA. Is this likely to
be a problem? Why or why not?
The liver cell was dividing at the rate it did
for a reason! The body knows how often the
liver cells need to be replaced. It this rate
increases, there could be too many cells.
This could result in the formation of a tumor.
A tumor could negatively impact the
function of the liver.
6. Many of the drugs given to people to fight their
cancers damage the cellular structures involved in
mitosis. Explain:
a. why these drugs kill a higher percentage of
cancer cells than normal cells.
Cancer cells are divided more frequently.
b. whether you would expect the drugs to have
more of an effect on normal white blood cells or
on normal neurons.
Neurons don’t reproduce at all! So they aren’t
doing mitosis and the drugs won’t affect them.
 Explain the main reasons why the outcomes at
age 35 for the two women with cervical cancer
vary in the following scenario:
 The two women had different outcomes
because one had sufficient health care and the
other did not. In this case, good health care
means more preventive measures. The girl with
good access to health care was was screened
and vaccinated early. This reduced the risk of
getting cancer. When cancerous tissue was
found, it was removed right away. This shows
that preventive health care is essential to avoid
cancer related deaths.
AQ #8
 Based on the cancer case study, how is cancer
related to the social, economic, and
environmental aspects of sustainability?
 Social-lifestyle & behavior choices can increase
risk; pain & suffering
 Economic-high cost of care, lack of productivity
 Environmental-exposure to tobacco smoke, air
& water pollution increase cancer risk