Unit 9: The Cell Cycle

Transcription

1 Unit 9: The Cell Cycle Name: Period: Test Date: 1

2 Table of Contents Title of Page Page Number Teacher Stamp Unit 9 Warm-Ups 3-4 Cell Cycle/Interphase Notes 5-6 DNA Replication Notes 7-8 DNA replication W.S Cell Cycle Practice Cancer Notes 16 Cancer Read and Questions

3 UNIT 9 WARM-UPS Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: 3

4 Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: Question: Date: Answer: 4

5 Cell Cycle Interphase Notes Today we re going to talk about What is the Cell Cycle? The Cell Cycle % of cell s time spent in three stages that are collectively called Control of the Cell Cycle Cells have red light-green light that turn cell division on and off These switches are called checkpoints G1 Checkpoint- Is the cell enough and large enough for division? G2 Checkpoint- Checks DNA replication for and repairs occur if necessary. Mitosis Checkpoint- triggers from mitosis and beginning of G1 phase. CYCLINS that regulate the timing of the cell cycle in eukaryotic cells. During Interphase, cells: G1 phase Cell grows while carrying out routine functions S phase (DNA Synthesis) The cell s DNA is during this phase G2 phase Preparation for DNA checked for After G1, S, and G2 Phases The cell would begin Mitosis (M Phase) Mitosis is cell division. Mitosis guarantees genetic continuity by the production of. The new cells carry out the same cellular processes and functions as those of the parent cell. 5

6 interphase INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE TELOPHASE ANAPHASE METAPHASE PROPHASE -Chromatin (genetic material) to form a chromosome. -Nucleus begins to. begin to move to opposite ends. -The begins to form between the centrioles. -Chromosomes become to the spindle fibers by their centromeres. -The chromosomes begin to line up in the of the spindle with each chromatid attached to a separate spindle fiber by its centromere. M = M -Chromosome copies are by microtubules. -Chromatids move to opposite of the cell. -Each chromatid is now a separate. A = A. - are pulled to opposite poles - begins to form around the chromosomes - daughter cells are formed. INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE CYTOKINESIS -After mitosis, two are formed - grows to enclose each cell -Forming two genetically cells INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE INTERPHASE 6

7 DNA REPLICATION NOTES DNA HEIRARCHY: Why does DNA need to replicate? Let s quickly review DNA structure in prokaryotes and eukaryotes. Prokaryotes Eukaryotes stranded Single Found in A-T C-G Double stranded helix Found in A-T C-G 7

8 DNA strands are. DNA is read to. Strand on the left 5 3 Strand on the right 5 3 Replication of DNA In bacteria begins at a point in the Proceeds in directions until the chromosome is separated In eukaryotic cells replication can be occurring at of places along the DNA strand How does DNA replicate? What has to happen to the DNA strand first? How does this happen? help the double strand An enzyme called breaks the bonds between the strands! Once strands are separated and unwound, what happens? DNA adds free that to the exposed strand (using Base Pairing Rules!!!) DNA polymerase binds the free nucleotides to the strand. DNA polymerase also checks for. It can only advance nucleotides if the previous nucleotide is paired. Can polymerase correct stuff? Yes No Maybe (circle one) DNA Replication is Semi-Conservative During replication, existing DNA strands serve as for new complementary strands Complementary Base Pairing Practice Parent Strand = ATGGCGTCAT GCTTAGATTA Daughter Strand =

9 DNA Replication Practice The double helix of DNA unwinds and each side serves as a pattern to make a new molecule. DNA Replication DNA carries the information for making all of the cell's proteins. These proteins implement all of the functions of a living organism and determine the organism's characteristics. When the cell reproduces, it has to pass all of this information on to the daughter cells. Before a cell can reproduce, it must first replicate, or make a copy of, its DNA. Where DNA replication occurs depends upon whether the cells is a prokaryote or a eukaryote (see the RNA sidebar on the previous page for more about the types of cells). DNA replication occurs in the cytoplasm of prokaryotes and in the nucleus of eukaryotes. Regardless of where DNA replication occurs, the basic process is the same. DNA Replication is a process that must be done exactly. When it is not completed correctly, mutations (mistakes) then result. In order to make sure that everything is replicated correctly, you will want to make sure that you use the proper base pairing rules: A will bond with T only, and G will bond with C only. Directions: For each strand of DNA, show the three steps to demonstrate that you could replicate the DNA correctly. See the example for details if you don t recall how. Example: TCCTG ACCCC GCCGG GATAT CCTTC TACCT CCAAA TGTAT 9

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11 Mitosis Practice 1 The diagram below shows six cells in various phases of the cell cycle. Note the cells are not arranged in the order in which mitosis occurs and one of the phases of mitosis occurs twice. Use the diagram to answer questions ) Cells A and F show an early and a late stage of the same phase of mitosis. What phase is it? 2) What structure is breaking down during A & F? 3) Which cell is in anaphase? 3) Which cell is in the first phase of mitosis? 4) In cell A, what structure is labeled X? 5) Cell C is in what phase of mitosis? 6) Place the diagrams in order from first to last. 8) What is the longest phase of the cell cycle? 9) Why is mitosis important? 11

12 Cell Cycle and Mitosis Practice 2 Label the parts of the cell cycle diagram and briefly describe what is happening: A B C D E F G H I J 12

13 The Cell Cycle (Phases are in order) Interphase Prophase Metaphase Anaphase Telophase Interphase 1. Chromosomes move to the middle of the cell during what phase? 2. What are sister chromatids? 3. What holds the chromatids together? 4. When do the sister chromatids separate? 5. During which phase do chromosomes first become visible? 6. During which phase does the cleavage furrow start forming? Complete the table by checking the correct column for each statement. Statement Interphase Mitosis 7. Cell growth occurs 8. Nuclear division occurs 9. Chromosomes are finishing moving into separate daughter cells. 10. Protein production is high 11. Chromosomes are duplicated 12. DNA synthesis occurs 13. Cytoplasm divides immediately after this period 14. Mitochondria and other organelles are made. The Animal Cell Cycle Phases are out of order for questions

14 15. Which cell is in metaphase? 16. Cells A and F show an early and late stage of the same phase of mitosis. What phase is it? 17. Which cell is not in a phase of mitosis? 18. A new membrane is forming in B. What is this phase called? 19. Sequence the six diagrams in order from first to last. 20. What is the end product of mitosis? 21. If the original cell has 46 chromosomes, how can each new daughter cell also have 46 chromosomes? 22. What is the main difference between cell division in plants and animals? 23. What is the purpose of mitosis? 14

15 A. B. C. D. E. 15

16 CANCER NOTES When control is lost and there is a mistake in the cell cycle: Cancer is an dividing of cells Cancer: A Mistake in the Cell Cycle? It is believed that cancer is caused by changes controlling production of involved in the cell cycle. It can result from 1. A failure to produce certain 2. The of enzymes 3. The production of enzymes at the When environmental factors trigger the damaged genes into action, cancer is expressed. Cancerous cells affect normal cells by forming masses of tissue called. Tumors deprive normal cells of their nutrients. In the final stages, cancer cells enter the and spread throughout the body, forming new tumors. Some promising cancer research We have a in our body called p53 that is known as the. detects damage in and commands cell to stop dividing so damage can be repaired *Almost 50% of human cancers are associated with a mutation in the tumor suppressor gene p53. Cells have red light-green light switches that turn cell division on and off These switches are called checkpoints : o G1 Checkpoint- Is the cell healthy enough and large enough for division? o G2 Checkpoint- Checks DNA replication for errors and repairs occur if necessary. o Mitosis Checkpoint- triggers exit from mitosis and beginning of G1 phase. : Proteins that regulate the timing of the cell cycle in eukaryotic cells. 16

17 Cancer Cell Cycle Gone Wrong Practice What is cancer? o Cancer is the uncontrolled growth and division of cells. Cells will keep growing and dividing, even if your body does not necessarily need them. This means that there is a malfunction in the body in knowing when to start and stop mitosis. The cell usually spends most of its time in interphase and spends a very small amount of time in actual cell dividing phases. However, cancer cells are in a rapid state of cell division and spend much more time out of interphase. How Are Cancer Cells Different Than Regular Cells? o Cancer cells behave differently than normal functioning cells. This also means that they likely have different physical characteristics. Cancer cells often have these traits: They spend less time in interphase therefore they are dividing more! They have uncontrolled mitosis the means they do not stop division after a certain point. They grow faster than normal cells They can break away from groups of cells and travel to other places in the body. They have a different physical structure often with parts that allow them to grip and grab onto other cells and tissues ***Examples of different cancer cells with many gripping structures*** What Are Some Causes of Cancer? o There are many causes of cancer. All of these things increase the likelihood of cells becoming mutated. Mutated cells may not be normal and develop an incorrect cycle of mitosis. They will then keep reproducing at a high rate, causing the body to put lots of energy into their production and upkeep. All of this energy being devoted to these cancer cells causes other normal cells to suffer and can ultimately lead to death. o Causes of Cancer (things likely to increase the chance of mutated cells) Chemicals many chemicals cause mutation, leading to problems with mitosis Ultraviolet (UV) Radiation When tanning or exposed to the sun, you absorb UV light. UV light causes DNA to be mutated which can alter the cell mitosis cycle in the future. Viruses an example is the HPV virus, which is known to cause cervical cancer in females if they are exposed. X-rays they radiate cells, causing mutations Genetics -- some people are born with genes that are more likely to mutate over time or have cancerous properties. If cancer runs in the family, then you are likely to have a higher risk of getting cancer. 17

18 What Is A Tumor? o A tumor is a cluster of cells going through uncontrolled mitosis. o You can have two types of tumors: Benign Tumors these tumors have cells that do NOT migrate to other parts of the body and do not harm other parts of the body Malignant Tumors these tumors have cells that can migrate to other parts of the body, potentially causing the cancer cells to spread in the body When a tumor or cancer cells have spread from their original source, this is called metastasis. ***This picture gives information on how a general body mole looks different than a skin cancer*** If You Get Cancer, How Can It Be Treated? o Each cancer is different, so treatments may vary from person to person. Additionally, how advanced the cancer is will impact what type of treatment you get. o Biopsy First, doctors usually want to analyze the first sign of cancer. This is usually seen as a tumor. Doctors want to look at the tumor to see if it is cancerous or not. If the tumor is cancerous, doctors then want to know if it is benign or malignant. To determine these things, doctors take a biopsy. In a biopsy, the doctor removes a sample of the cells from the tumor to analyze under a microscope to determine the nature of the cells. o Radiation Therapy If the tumor is cancerous, you can direct radiation at the tumor. The radiation will kill the cells in the tumor, causing the tumor to shrink and hopefully die. o Chemotherapy To kill cancer cells in the body, doctors can inject powerful drugs into the body. This is usually done as an injection of drugs into the blood. These drugs kill cells quickly and aggressively. These drugs will also kill many normal cells in the body. So, this therapy can make people very weak and frail. o Surgery Often, the doctors will remove the tumor and attempt to remove the cancer from the body and reduce the chance of it spreading. 18

19 What Is Cancer? Cancer is when what cell process is uncontrolled?: Normal cells of the body spend most of their time in which phase of mitosis?: How Are Cancer Cells Different From Regular Cells? List the 5 ways that cancer cells are different than normal cells of the body: What is one way that cancer cells are physically different than normal cells? What Are Some Causes of Cancer? How do you end up dying from cancer? Explain how the body loses energy due to cancer in the space below: List the different possible causes of cancer given in the reading: o All of these items increase the likelihood of cells becoming, which means that cells may not repair and follow a proper cell division cycle. 19

20 What is a Tumor? A tumor is defined as a There are two type of tumor. They are: OR o Name each type of tumor below and state what makes it different than the other type: o Define what happens if the body is undergoing metastasis: How is Cancer Treated? In order to determine if a tumor is cancerous, a doctor will take a Describe in the space below what is done during this procedure and why: of it. If a tumor is deemed cancerous, then one could do a variety of treatments. For each treatment, state what is done to treat the tumor: o Surgery o Chemotherapy o Radiation Treatment 20