Cell+Division+8th

Mitosis

View this [|video] on mitosis:

**The Language of Cell Division** (When finished, hand in to your teacher. **20 points** Write a description of the following terms before continuing this exercise: (you may use Google or any other search engine) 1. mitosis 2. interphase 3. cytokinesis 4. diploid 5. chromosome 6. chromatid 7. replication 8. somatic 9. DNA 10. cell plate
 * Activity One **


 * Activity Two **

**Mitosis is the dividing phase of the cell cycle. In the diagram below, you will see the cell cycle and its phases:**


 * 1) What is the [|cell cycle]? (Use this site to answer the next six questions.)
 * 2) What happens in G-1 phase?
 * 3) S-phase seems incredibly long. What are the important events of this phase?
 * 4) G-2 phase is the shortest part of interphase. What happens in this phase?
 * 5) G-0 isn't even on the wheel. What is the purpose of this phase?
 * 6) In terms of hours, how long does the cell cycle last in mammals?

Remember that there are three distinct phases of the cell cycle: **Interphase, Mitosis**, and **Cytokinesis**. On [|this site], you will read about why cells divide and see a short video of the cell cycle, with emphasis on interphase. Then move on to the mitotic phase: **prophase, metaphase, anaphase and telophase.** Answer the following questions about the cell cycle:
 * Activity Three **


 * 1) Explain the reasons why a cell might divide.
 * 2) Two events are necessary for a successful cell division: a) [|the copying of genetic information] to ensure the daughter cells each have a complete set, and b) the successful division of the cytoplasm into two daughter cells. During which two phases of the cell cycle do these two events occur?
 * 3) Describe the events of **Mitosis**.
 * 4) How does cytokinesis take place in plant cells?
 * 5) How does cytokinesis take place in [|animal cells]?

Watch [|videos of mitosis] in plant and fish embryonic cells. Select from the menu on the left side of the screen under the **movies** heading.

**Activity Four** ** It's a numbers game, acutally. Let's track the number of chromosomes and sister chromatids throughout the cell cyle. ** 1. Look at the cell in prophase. How many chromosomes do you see? How many sister chromatids do you see? 2. Look at the cell in metaphase. How many chromosomes do you see? How many sister chromatids do you see? 3. Look at the cell in anaphase. How many chromosomes do you see? How many sister chromatids do you see? 4. Look at the cell in telopohase. How many chromosomes do you see. How many sister chromatids do you see? 5. Think about what comes next. Each daughter cell will enter _ ?_ of interphase. How many chromosomes does it have? How many sister chromatids? 6. The cell, which is still in interphase, will enter_?_. What happens during this phase? How many chromosomes does it have? How many sister chromatids? 7. Now which phase will the cell enter? How many chromosomes does it have? How many sister chromatids?

Build a table that shows the numbers of chromosomes and chromatids at each phase: --
 * __Phase__ || __Number of Chromosomes__ || __Number of Sister Chromatids__ ||
 * Prophase ||  ||   ||
 * Metaphase ||  ||   ||
 * Anaphase ||  ||   ||
 * Telophase ||  ||   ||
 * G-1 ||  ||   ||
 * S ||  ||   ||
 * G-2 ||  ||   ||


 * Activity Five **

What mechanisms cause the cell to divide?
 * 1) One reason the cell enters cell division is that it has more or less outgrown itself, gotten too big for its britches, so to speak. Find out how this happens.

media type="custom" key="3184648"

2. A second reason cells divide is that that are part of a growing organism, for example, an embryo.

3. Cells also divide to repair damage (such as a cut or wound) or to replace a dead cell.

4. Cells also divide because they become [|cancerous]. What other factors determine when (or if) the cell will divide? As you can see from the diagram above, without the cdk molecule (cdk stands for cyclin dependent kinase) and the cyclins, the cell could not move through the phases of interphase and mitosis. The cell would not divide and would remain in G-0. The cdk molecule is like the engine and the cyclins are like a gearbox that tells the engine when to idle and when to go forward.

Activity Six - Review and Test View this [|video on mitosis] and then review the following information. [|This review] has very good photographs of the individual phases of mitosis in both plant and animal cells. You must be able to recognize the phases on your test. Take this [|practice quiz]: Write the answers on a separate sheet of paper. This is a 23-point grade. Activity Seven - Project You will be completing a project involving stem cell research. At the end of your project you will have written a thoughtful, well-researched letter to a member of Congress persuading him/her to change his current views on stem cell research. Helpful websites include the [|National Institutes of Health] site, the [|Nova] science site, scientific journals such as the [|NewScientist], the [|Nature News] site, and legitimate religious websites such as this [|Religious Tolerance website.] [|This site] may be useful to you for your basic research. If you have a religious preference, find out how your church stands on the issue of stem cell research. If you have difficulty finding information on your particular faith/denomination, you may interview your pastor. However, you must list the pastor's name, church, and church address for your works cited. If you don't find everything you need on the above listed sites, Google for the information. Be sure to document all sites and interviews. I encourage you to make a Word document for your notes; cut and paste each websites beneath the notes for that site. Save to the hard drive and to your jump drive. You will choose a Tennessee senator or representative (or even President Obama) and write a letter to him (her?) explaining your views on stem cell research and imploring him to modify his current policy on stem cell research. Of course, this means you will have to be familiar with the various politicians' views on stem cell research and select accordingly. The person you choose must have a viewpoint that is different from yours. You must present no fewer than three points which you will thoroughly explain, backed up by current research and literature on the subject. You must include your research in the form of a separate Works Cited. If you have never written a [|persuasive letter], you may consult this source for very clear and sequential steps. In addition, we will follow [|this template.] A [|rubric] is included for your reference.
 * 1) Important Facts To Remember About Mitosis
 * 1) Mitosis is a process than involves only one parent cell.
 * 2) Mitosis results in the formation of two daughter cells.
 * 3) Both daughter cells are exact replicas of the parent cell.
 * 4) The parent cell is a diploid cell.
 * 5) Both daughter cells are diploid cells.
 * 6) In mitosis, replication of the DNA occurs one time.
 * 7) In mitosis, the chromosomes divide one time.
 * 8) In mitosis, division of the cytoplasm occurs one time.
 * 9) In humans, mitosis occurs primarily for the purposes of growth and repair.
 * 10) Cancer is mitosis gone wild: the cell can't stop dividing and it can't die.
 * Project Information **
 * Research **
 * Task **
 * Assessment **

**Activity Eight**

Meiosis  Log on to this [|website] and follow directions to complete the activities. Observe that there are two columns on the main page.

> > > In the above diagram, notice that there are two replicated homologous chromosomes. We will assume that the orange chromosome was inherited from the mother and the blue chromosome was inherited from the father. These chromosomes are in Prophase I of meiosis. It is during this phase that crossing over takes place between homologous chromosomes. (Remember that homologous chromosomes are the two matching chromosomes that we inherit from our parents.) The chiasma is the point at which crossing over takes place. At the end of crossing over, the two pairs have exchanged hereditary information; the chromosome (orange) inherited from Mom now contains information from Dad's chromosome. By the same token, the chromosome (blue) inherited from Dad contains information from Mom's chromosome. Neither is exactly like it was before. Because the genes have recombined on different chromosomes, we call the resulting homologous chromosomes "recombinant chromatids." > > > **Activity Ten** > **Mitosis and Meiosis Review** > Having completed the mitosis tutorial earlier in this unit, you should now log onto the [|meiosis tutorial.] > Browse through each topic, answering the questions on the worksheet as you get to them. Remember that you already have a copy of this tutorial; it is in the same packet as the mitosis tutorial. > > Complete the [|Onion Root Tip Activity.] Follow the directions to classify all 36 cells. Then calculate the percentage of cells in each phase. Be sure to enter your data into the data table. If you need a calculator, use [|this one]. **Try this [|self-quiz] and record your correct choices.**
 * Select the TO PONDER choice in the left column. Answer the questions, using the highlighted words to find the answers.
 * Next read the Objectives in the left column. Notice that there are 11 terms that are highlighted in this section. Click on each of the terms and write down each term with its definition in your notes.
 * <span style="background-color: #f8fcf9; font-family: 'Comic Sans MS',cursive; font-size: 140%;">Then, from the same column, read the Introduction and Background.
 * **<span style="font-family: 'Trebuchet MS',Helvetica,sans-serif; font-size: 120%;">In the right column, select Meiosis, Part I. Read all the information and answer the three questions. **
 * <span style="background-color: #f8fcf9; font-family: 'Comic Sans MS',cursive; font-size: 140%;">Before continuing with the first exercise, <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif; font-size: 120%;">**ask your teacher for the materials you need for this part.**
 * <span style="background-color: #f8fcf9; font-family: 'Comic Sans MS',cursive; font-size: 140%;">Complete the other two exercises, answering questions as they arise. [[image:meiosismorph.gif]]
 * <span style="background-color: #808080; color: #ff0000; display: block; font-size: 140%; text-align: center;">Activity Nine
 * **Your teacher will give you a worksheet for this activity. Follow the directions on the sheet, using the following links:**
 * [|Lew-Port site] **This is a comprehensive site with many links to other good biology websites.**
 * [|Sumanas animations site] **Click on General Biology.**
 * [|Biology In Motion site.] **Click first on Cell Division Exercise and then on** **Practice Meiosis.**
 * [|University of Arizona site.] **Work through each topic beginning with Part 1: Reproduction.**
 * [|The Biology Corner] site. **You will already have a copy of this worksheet.**
 * **Complete the vocabulary search, using the above websites or the Biology text in the classroom.**
 * **In the diagram below, see how homologous chromosomes exchange genetic material to make each organism different from every other organism on the planet. This explains how you became the unique individual that you are!**

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 140%;"> > <span style="background-color: #f8fcf9; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 160%; text-align: left;"> > > <span style="background-color: #00ff00; color: #000080; display: block; font-size: 120%; text-align: center;">**You should be ready for your test October 26, 2009.**
 * <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 140%; text-align: center;">Important Points About Meiosis <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;"> <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 140%; text-align: center;">
 * 1) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">The purpose of meiosis is to produce cells that will be used in sexual reproduction.
 * 2) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In males, sperm are produced; in females, ova (eggs) are produced.
 * 3) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the genetic information (DNA) is copied once.
 * 4) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the cell divides twice.
 * 5) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, four daughter cells are produced.
 * 6) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the parent cells are diploid.
 * 7) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the daughter cells are haploid.
 * 8) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the daughter cells are genetically different from the parent cell.
 * 9) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">In meiosis, the process of crossing over occurs in Prophase I.
 * 10) <span style="background-color: #ecff00; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 112%; text-align: left;">Crossing over insures genetic variation in the offspring.