The Cell Cycle
The Cell CycleSEPUP Cell Biology: Activity 131What do cells need
energy for? Brainstorming!!Transport/movementObtain
food/energyProduce building blocks of cellsReproduce
2Lets 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 newor offspringcells.
3REGULATORS mount up! A group of cell-cycle control proteins
regulates thephases of the cell cycle to ensure that all events
neededfor normal cell division take place before division begins.
Cell-cycle regulation also ensures that specificcell types divide
at the right time and place. Forexample, in the human body red
blood cells must bereplaced about every 120 days. If the stem cells
thatdifferentiate into red blood cells become under- orover-active,
either too few or too many red blood cellsare produced. Regulation
of the cell cycle also ensuresthat a cell completes the growth and
synthesis phasesso that it will divide properly. When cell growth
anddivision proceed abnormally, cancer might result.
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5A 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 over-active, the wrong number of
red blood cells could be produced. Regulators are also important
because when cells grow and divide abnormally, cancer might result.
6In this activity we are going to be able to see cell division
happening in different types of cells:Red blood cellLiver cellNerve
cellSkin cellTo do this we will play the most spectacular board
game... The Cell Cycle!It's Game Time!
7Let'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? 8Assemble 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 #14Let the Cell Cycle Begin!9There 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.
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11DESTRUCTION: 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 dont 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!Possible Game Key Scenarios
12Something to think aboutWhat 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? 13Thinking Break #11. What has happened to your groups
cells so far?2. In what ways are your cells cycles the same?3. How
are they different?
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15Thinking Break #21. 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!
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17How were these cells different when it came to the cell
cycle?Nerve cellSkin cellLiver cellBlood cell18
19Liver CellDivided occasionallyCells often stayed in GoNormal
mitosis & cytokinesis produced two daughter cellsSometimes
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.20Nerve CellNada nothing.Why
is damage to nerve cells permanent?21Skin & Blood CellCells
grew and divided frequently.Normal mitosis & cytokinesis
produced two daughter cellsSometimes cycle did not work correctly
resulting in a destroyed cell.Sometimes that cell was not destroyed
and became cancerous. Cyclin accumulated.
22Cancer CellCell with a previous life that divided without
controls.Some of these cells were destroyed (did not happen in our
class).
23What 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!24Analysis Questions!1. Of the cell
types you investigated, which divide: frequently? Red blood cell,
skin cellb. occasionally, as needed? Liver cellc. never, or almost
never? Nerve celld. more frequently than normal and without
control? Cancer cell 252. What kinds of factors regulate a cells
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 growthS - DNA replicationG2 cell
growth & prepare to divideM - cell division
264. Why is it important for each of the following to be
regulated? Entry into the cell cycleA 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.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.275. 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.
286. Many of the drugs given to people to fight their cancers
damage the cellular structures involved in mitosis. Explain: 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 dont reproduce at all! So
they arent doing mitosis and the drugs wont affect them.29
30Explain 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.
31AQ #8Based 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 & sufferingEconomic-high cost of care, lack of
productivityEnvironmental-exposure to tobacco smoke, air &
water pollution increase cancer risk
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