CellDivision complete
.docx
School
Nelson Mandela High School**We aren't endorsed by this school
Course
BIOLOGY 20/30/35
Subject
Biology
Date
Dec 22, 2024
Pages
9
Uploaded by DrSardine4538
2018Name: _____Hamada _________________________________Date: ___________8 november _____________Student Exploration: Cell DivisionVocabulary:cell division, centriole, centromere, chromatid, chromatin, chromosome, cytokinesis, DNA, interphase, mitosisPrior Knowledge Questions (Do these BEFORE using the Gizmo.)1.Cells reproduce by splitting in half, a process called cell division. What do cells need to do between divisions to make sure that they don’t just get smaller and smaller?Cells need to grow and make extra copies of their parts, like organelles and proteins, so they are big enough to divide without getting smaller each time.______________________________________________________________________2.The genetic information of a cell is carried in its DNA(short for deoxyribonucleic acid). Whatdo cells need to do between divisions to make sure that a full set of DNA gets passed on to each daughter cell?__Cells need to copy all of their DNA before dividing so that each new cell gets a complete set of genetic information.____________________________________________________________________________________________________________________________________________Gizmo Warm-upOn the SIMULATIONpane of the Cell Division Gizmo, check that the Cycle Length is set to 12 hours. Click Play(), observe until the maximum number of cells is shown, and then click Pause().1.Look at the cells. Do they all look the same? ___No2.Cells that are in the process of dividing are said to be in mitosisor cytokinesis. Cells that are not dividing are in interphase. InterphaseCheck the Magnify box and move the cursor over the cells. A.Of the 100 cells shown, how many are in the process of dividing? Out of the 100 cells shown, 13 are in the process of dividing
2018B.Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the interphasestage of their life cycle? ____87__________________________C.Based on these two observations, would you say that a cell spends most of its life cycle in interphase or in mitosis/cytokinesis? ____________Interphase___________________
2018Activity A: Phases of the cell cycleGet the Gizmo ready: Click Reset().Select the DESCRIPTION tab.Click on the right arrow once so that Interphaseis shown.Question: What are the stages of the cell cycle?1.Observe: Click Playand hold the cursor over the cell. Observe the cell as it divides several times. (This happens quickly!) What do you notice happening during this process?_the DNA is copied, chromatids appear and the cell pulls apart_________________________________________________________________________2.Summarize: On the DESCRIPTION pane, read about each phase in the cell cycle. In the spaces below, sketch the cell in each phase and summarize what occurs in your own words.PhaseSketchSummaryInterphaseduring interphase, the cell grows and matures and then duplicates its DNAProphaseIn prophase, the first step of mitosis, the nucleus breaks down, and the loose strands of DNA (called chromatin) tighten and coil up to form visible chromosomes.MetaphaseIn metaphase, the second step of mitosis, the chromosomes line up in the middle of the cell.AnaphaseIn anaphase, the third step of mitosis, the chromosomessplit apart, and each half (called a chromatid) is pulled toopposite sides of the cell.TelophaseIn telophase, the final step of mitosis, a new nuclearmembrane forms around each set of chromosomes, andthe chromosomes loosen up back into chromatin.CytokinesisThe cell membrane pinches and divide the daughter cell(Activity A continued on next page)
2018Activity A (continued from previous page)3.Analyze: Use your summaries and the Gizmo to answer the following questions:A.What are the four phases of mitosis? ___Prophase ,Metaphase,Anaphase and Talophase _________________, _____________________, _____________________, _____________________B.During which phase is the DNA duplicated? ___S phase__________________C.What is the relationship between chromatin and chromosomes? ____Chromatin condense into chromosome in metaphase_____________________________________________________________________________D.In which phase are chromatidspulled apart? __Anaphase ___________________E.What is the role of the centrioles? ___Centrioles play a key role in cell division by helping to organize the mitotic spindle, which separates chromosomes. They also assist in forming cilia and flagella, aiding cell movement. ____________________________________F.In which phase does a new nuclear membrane develop? _____Telophase________________G.A cell has a single line of chromosomes. What is the phase? ___Metaphase__________H.During which three phases are individual chromosomes no longer visible?Interphase_____________________, _____Talophase ________________, ______Cytokinesis_______________4.Think and discuss: Why is it important that the cell’s DNA is duplicated before cell division? __It’s important for a cell’s DNA to be duplicated before division to ensure each new cell receives a complete set of genetic instructions. Without this, cells would lack essential DNA, leading to errors in cell function or survival._________________________________________________________________________________________________________________________________________________________________________________________________________________________5.Challenge: Human cells have 46 chromosomes. Each chromosome consists of a pair of identical chromatids attached together by a structure called a centromere. Once the chromosome has split, each chromatid is called a daughter chromosome. At the end of cytokinesis, how many daughter chromosomes will be found in each cell? Explain.
20184.__At the end of cytokinesis, each new cell will have 46 daughter chromosomes. This is because each original chromosome splits into two identical chromatids, and each cell gets one chromatid from each pair, maintaining the total at 46 chromosomes per cell.4o_________________________________________________________________________________________________________________________________________________________________________________________________________________________
2018Activity B: Duration of phasesGet the Gizmo ready: Click Reset.Select the TABLE tab.Question: What is the relative duration of each phase of the cell cycle?1.Collect data: Set the Cycle Lengthto 10 hours and click Play. Click Pausewhen the maximum number of cells has been reached. On the TABLE tab, click Record data. Record the number of cells in each phase of the cell cycle in the table below. Then click Play, wait for a while, and click Record data again. Repeat this process until you have recorded four sets of results, and then find the average number of cells in each phase.TrialInterphaseProphaseMetaphaseAnaphaseTelophaseCytokinesis18010322127910323238494244489112231Avg.82.751032312.Analyze: Which phase of the cell cycle is longest? ___Interphase_________ Shortest? ____M phase____Explain your answers: _____Interphase is the longest phase because the cell spends most of its time growing, replicating its DNA, and preparing for division. M phase (mitosis) is the shortest because it’s the phase where the cell rapidly divides into two new cells, a process that takes less time than the growth and preparation steps.___________________________________________________________________________________________________________________________3.Calculate: You can use your data to estimate the duration of each phase of the cell cycle. For example, if 8% of the cells were in prophase and the cell cycle was 10 hours long, then prophase would last 8% of 10 hours, or 0.8 hours (48 minutes).Use percentages to estimate the duration of each phase of the cell cycle. Show your work.Interphase: 0 845x10 = 8.45 8 hProphase: .0 077X10 = 0.77 46 . 2 min _________________________________________________________
2018Metaphase: 0 .01X10 = 0.1 6 minute______________________________________________________Anaphase: _0.025+ 10 = 0 . 25 15 min _______________________________________________________Telophase:_51.8 minutes _________________________________________________________Cytokinesis:_____1 hour_____________________________________________________
2018Extension: Cell populationsGet the Gizmo ready: Click Reset.Select the GRAPH tab.Set the Cycle Lengthto 5 hours.Question: How quickly do cells multiply?1.Collect data: Click Play to start a new simulation. Click Pause when the maximum number of cells is reached. View the total number of cells on the GRAPH tab. (Click the “–” button until the whole graph is visible.) Draw a sketch of this graph here.What is the general shape of the graph?___Linerb line upwards _________________________________________________________________________________________________________2.Analyze: Look closely at the graph. A.About how long did it take to grow the first 20 cells? ____15 hours ______________________B.About how long did it take to grow the last 20 cells? ______20 hours ____________________C.Would you say the rate of cell growth is increasing or decreasing? Explain._____Decreasing since the time it takes to grow 20 cells increases._________________________________________________________________________________________________________________________________3.Extend your thinking: In living organisms, the cell cycle is closely regulated. What do you think will happen if cell division is notcontrolled? 4.f cell division is not controlled, cells may divide too quickly or too slowly. This can lead to problems like cancer, where cells grow uncontrollably, or tissue damage if cells don't divide when needed. Proper control is important for healthy growth and function.__________________________________________________________________________________________________________________________________________________
2018___________________________________________________________________________________________________________________________________________________________________________________________________________________________