Presentation on theme: "The Cell Cycle SEPUP Cell Biology: Activity 13 What do cells need energy for? Brainstorming!! Transport/movement Obtain food/energy Produce building."— Presentation transcript:
What do cells need energy for? Brainstorming!! 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 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.
I n 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! It's Game Time!
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?
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 Let the Cell Cycle Begin!
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.
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! Possible Game Key Scenarios
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!
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