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Cell Division

Cell Division. Permanent Marker Experiment. Permanent Marker experiment – take a permanent marker and put a bunch of dots on the back of your hand. Then put a bunch of dots on the palm of that same hand.

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Cell Division

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  1. Cell Division

  2. Permanent Marker Experiment Permanent Marker experiment – take a permanent marker and put a bunch of dots on the back of your hand. Then put a bunch of dots on the palm of that same hand. Make a prediction – Predict what side of your hand do you think the marker will disappear first, will it be the palm of your hand, or the back of your hand? Why did you make that prediction? Record daily results – every day, make a record of what is happening to the permanent marker stain. In three days we will write the results that we see and hand it in to Mr. Willard.

  3. Cell Division In groups, discuss what you know about cells in humans and or plants. Discuss as a class.

  4. Cell Division Have you ever wondered why we have dead skin that peels off our body? What do you think you are peeling away? Imagine all the bumps, scraps, cuts, and etc… you have had your entire life. If those scraps never disappeared, what do you think your body will look like? Think of all the sun burns and or blisters you have ever had in your life. What do you think your body will look like if your skin never peeled away? What about when you were a baby, do you think all the cells in your body stayed the same size?

  5. Three Main Functions of Cell Division • There are three main functions of cell division: • Growth • Repair • Reproduction

  6. Growth All organisms start out as a single cell. All living things are composed of one or more cells. Multi-cellular organisms, such as humans, undergo cell division to increase in size. As a cell grows, the volume of they cytoplasm increases at a greater rate than the surface area of the cell.

  7. Growth Once the cytoplasm reaches its breaking point, i.e. the cell grows beyond a certain size, it cannot function effectively. As such, the cell will divide into two smaller cells that will then preform and function efficiently. After a certain number of cellsare created, a multicellularorganism, will have its cells undergo a process to form tissues and organs.

  8. Repair Multicellular organism repair damaged cells through cell division. You do not go through life with the exact same cells you had when you were born. Cells will die, fall off (or can be peeled away) and then are replaced through cell division.

  9. Repair • Humans – when you get cut you have a scab that is created overtop of the cut. • That scab is made up of blood clotting and your body reproducing cells really quickly. • The blood hardens, cells are created to protect the cut. • New cells are then divided underneath the cut and replace the cut with new tissue. • Trees do the same thing – • if you examine a tree where a branch has fallen off (or been cut off) the inner cells of the bark divide • New cells are produced to create new bark tissue, which covers and protects the damaged cells.

  10. Reproduction • Unicellular organisms, such as a paramecium, use cell division to reproduce. • A single-celled bacterium uses cell division to form two identical bacteria. • Ever wonder how we all get sick during flu season, we all tend to get sick by the same virus or bacteria? • Have you ever wondered what was in a flu shot?

  11. Cell Division Notice how during this lesson, this picture kept showing up? Take a close look, do both of these cells look really similar? This is an enhanced image of what two cells look like when they are dividing. All forms of cell division create an exact replica of its other cells.

  12. Cell Division Final thoughts on Cell Division part one – how many cells do you think the human body has? Take a guess. We have well over 100 trillion cells. Now time to do some math – Cell Division equation Number of Cells = (starting number of cells)(number of cell multiples at each division)n where n = number of cell divisions.

  13. How many Cells Do you have? • Example – how many cells do you have when you have six cell divisions and if an organism starts with one cell that has a cell division multiple of two? • Number of cells = (1)(2)8 Number of Cells = 256

  14. Assignment In the Workbook – page 22 – 23 In the Textbook - page 38, questions 3, 5, 6, 7, 9 (skin cells are tissue), 11, 13, 14

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