Cellfunc

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Cellfunc

  1. 1. Cell Functions ~ Growth and Mitosis ~ Biology Basics Review!
  2. 2. Section One Surface Area/Volume of Cells
  3. 3. How Large Can A Cell Grow? <ul><li>That is a very difficult question to answer. </li></ul><ul><li>Use the following diagram to review some parts of a typical cell. </li></ul><ul><li>Cell Membrane – The Container </li></ul><ul><li>for the cell. </li></ul><ul><li>Nucleus – Controls cell activity </li></ul><ul><li>Chromosomes – Contain genetic </li></ul><ul><li>information </li></ul><ul><li>Cytoplasm – Living material </li></ul><ul><li>between nucleus and membrane. </li></ul>
  4. 4. Cell Membrane <ul><li>The cell membrane is the container for the cell </li></ul><ul><li>All nutrients that enter the cell must pass through the cell membrane. </li></ul><ul><li>All wastes produced by the cell must pass through the cell membrane. </li></ul><ul><li>As the surface area of the cell membrane increases: </li></ul><ul><li>> More nutrients can enter. </li></ul><ul><li>< More wastes can leave. </li></ul>
  5. 5. Surface Area <ul><li>Select the cell from the diagrams below that has the greatest surface area . </li></ul><ul><li>A. Nerve Cell B. Adipose (Fat) Cell C. Plant Cell </li></ul><ul><li>The answer is A – The nerve cell has the largest surface area . </li></ul><ul><li>Which cell has the largest volume ? </li></ul><ul><li>The answer is B – Volume is a measure of the fluid part of the cell. </li></ul>
  6. 6. Review… <ul><li>As a cell grows, the surface area of the cell membrane increases. </li></ul><ul><li>As the same cell grows, the volume (amount) of cytoplasm increases. </li></ul><ul><li>As the volume increases, more nutrients and wastes must pass through the cell membrane. </li></ul>
  7. 7. Try These Questions: <ul><li>Select the letter of the correct answer from the list below: </li></ul><ul><li>All materials needed by a cell must pass through the ______________. </li></ul><ul><li>The volume of a cell is a measure of the amount of ______________. </li></ul><ul><li>The ____________ amounts required by a cell increase as the cell grows. </li></ul><ul><li>The ____________ determines how much waste can leave the cell. </li></ul>A. membrane D. volume B. nutrient E. surface area C. cytoplasm F. wastes
  8. 8. Answers: <ul><li>All materials needed by a cell must pass through the ______________. </li></ul><ul><li>The volume of a cell is a measure of the amount of ______________. </li></ul><ul><li>The ____________ amounts required by a cell increase as the cell grows. </li></ul><ul><li>The ____________ determines how much waste can leave the cell. </li></ul>membrane cytoplasm nutrient surface area
  9. 9. Section Two Experimenting With The Size of Cells
  10. 10. Section One Review… <ul><li>Our last exercise showed that large cells may have large volumes but comparatively small surface areas . </li></ul><ul><li>The size of the cell determines the amount of nutrients required and the amount of wastes that are produced. </li></ul><ul><li>The surface area of the cell membrane determines the amount of nutrients that can enter and the amount of wastes that can leave the cell. </li></ul>
  11. 11. Surface Area vs. Volume <ul><li>Does the surface area of a cell increase at the same rate as the volume of the cell? </li></ul><ul><li>To answer this question, let’s look at an experiment in which seven volumes of a growing cell were selected. </li></ul><ul><li>Note: If the cell membrane cannot increase enough to support the increased size of the cell, the cytoplasm cannot get enough nutrients, and the cell dies. </li></ul><ul><li>Information: Cell sizes are measured by using the micron (“ μ ”). One micron equals 0.001 millimeters. Volume (cytoplasm) is measured in cubic microns ( μ 3 ), and surface area (cell membrane) is measured in square microns ( μ 2 ). </li></ul>
  12. 12. Experimental Results <ul><li>The ratio* shows the balance between the cytoplasmic volume and the </li></ul><ul><li>membrane’s surface area . </li></ul><ul><li>A ratio of 1.0 to 1 shows that the cytoplasmic volume is balanced by the </li></ul><ul><li>surface area of the membrane. </li></ul>1.3 to 1 378 500 1.2 to 1 326 400 1.1 to 1 269 300 1.0 to 1 205 200 0.8 to 1 129 100 0.6 to 1 81 50 0.2 to 1 6 1 Ratio* Volume/Surface Area (Cytoplasm/Membrane) Cell Surface Area ( μ 2 ) Cell Volume ( μ 3 )
  13. 13. Graph of Data: <ul><li>As the cell increases in size, the cytoplasmic volume increases faster than the surface area of the cell membrane. </li></ul><ul><li>A graph of the results shown in the chart on the previous slide helps you understand that cell growth is limited by the surface area of the cell membrane. </li></ul>
  14. 14. Results… <ul><li>Note: When the size of the cell grows larger than the fourth selection, the area </li></ul><ul><li>of the membrane is less than the volume of the cytoplasm. </li></ul><ul><li>Cells larger than your fourth selection have membranes too small to bring in </li></ul><ul><li>enough nutrients and get rid of the wastes that build up in the cytoplasm. </li></ul>
  15. 15. Try This Question: <ul><li>Which of the following becomes stale first? </li></ul><ul><li>A. A loaf of bread sliced into two pieces. </li></ul><ul><li>B. A loaf of bread sliced into many pieces. </li></ul><ul><li>C. An uncut loaf of bread. </li></ul><ul><li>The answer is B – As the bread is divided into more pieces, the surface area of the bread increases and more of the bread is exposed to the air. </li></ul>
  16. 16. Now, You Should Be Able To Answer This Question… <ul><li>What does the cell do to increase its surface area when it grows too large? </li></ul>ANSWER : The cell increases its surface area by dividing. The total amount of membrane area that is exposed to the environment after division is greater than before. Each new cell is now better equipped to absorb nutrients and get rid of waste. <ul><li>Cell division increases the surface area of cells so that: </li></ul><ul><ul><ul><li>More nutrients now can enter the cells. </li></ul></ul></ul><ul><ul><ul><li>More wastes now can leave the cells. </li></ul></ul></ul>
  17. 17. Review… <ul><li>As the cell increases in size, more nutrients are needed, and more wastes are produced. </li></ul><ul><li>When the cell membrane is too small to support the volume of cytoplasm, the cell divides . </li></ul>
  18. 18. Try These Questions: <ul><li>Select the letter of the correct answer from the list below: </li></ul><ul><li>Cell _____________ increases the surface area of a cell. </li></ul><ul><li>A cell increases its surface area to absorb more ____________ by dividing. </li></ul><ul><li>The _____________ of the cell membrane limits cell growth. </li></ul><ul><li>As the cell grows, the surface area increases ___________ than the volume. </li></ul>A. surface area D. slower B. faster E. volume C. division F. nutrients
  19. 19. Answers: <ul><li>Cell _____________ increases the surface area of a cell. </li></ul><ul><li>A cell increases its surface area to absorb more ____________ by dividing. </li></ul><ul><li>The _____________ of the cell membrane limits cell growth. </li></ul><ul><li>As the cell grows, the surface area increases ___________ than the volume. </li></ul>division nutrients surface area slower
  20. 20. Section Three Chromosomes in Cell Division
  21. 21. What Makes One Organism Different From Another? <ul><li>Study the following chart. </li></ul>14 Land No Garden Pea 254 Water No Shrimp 46 Land Yes Human 78 Land Yes Dog 38 Land Yes Cat 26 Water Yes Frog Chromosome Number Habitat Backbone Organism
  22. 22. Chromosomes <ul><li>Of the three categories listed on the previous slide, which one best determines what the organism looks like? </li></ul><ul><li>Answer – Chromosome Number. </li></ul><ul><li>Chromosomes have the information for the structure of the organism, and how the organism functions. </li></ul><ul><li>Notice that each type of organism has a characteristic number of chromosomes. </li></ul><ul><li>These chromosomes are found in pairs. </li></ul><ul><li>How many pairs of chromosomes are found in each frog cell? ______ </li></ul><ul><li>How many pairs of chromosomes are found in each dog cell? ______ </li></ul><ul><li>How many pairs of chromosomes are found in each human cell? ______ </li></ul>13 39 23
  23. 23. Review… <ul><li>Chromosomes contain information that determines what the organism looks like and how it functions. </li></ul><ul><li>Each type of organism has a definite number of chromosomes in each cell. </li></ul><ul><li>Chromosomes are found in pairs. </li></ul>
  24. 24. Try These Questions: <ul><li>Select the letter of the correct answer from the list below: </li></ul><ul><li>The ________________ contain all the information about an organism. </li></ul><ul><li>The chromosomes within a cell are found in ________________. </li></ul><ul><li>Different kinds of organisms have ___________ numbers of chromosomes. </li></ul><ul><li>All the cells making up an organism have ____________ number of chromosomes. </li></ul>A. different D. the same B. membranes E. groups C. chromosomes F. pairs
  25. 25. Answers: <ul><li>The ________________ contain all the information about an organism. </li></ul><ul><li>The chromosomes within a cell are found in ________________. </li></ul><ul><li>Different kinds of organisms have ___________ numbers of chromosomes. </li></ul><ul><li>All the cells making up an organism have ____________ number of chromosomes. </li></ul>chromosomes pairs different the same
  26. 26. Drosophila <ul><li>Each chromosome has genes (information) for many different traits. </li></ul><ul><li>For example, the small fruit fly called Drosophila has 4 pairs of chromosomes in each cell. </li></ul><ul><li>Look at the genes found on part of one of </li></ul><ul><li>the chromosomes. </li></ul>eye color wing shape body color bristle shape <ul><li>The other chromosome of the pair (  ) also has genes for the same traits. </li></ul><ul><li>Pairs of chromosomes that contain genes for the same traits are called </li></ul><ul><li>homologous chromosomes . </li></ul>
  27. 27. Drosophila Dividing… <ul><li>Let’s look at two Drosophila cells in the process of dividing. </li></ul><ul><li>Remember – Only one of the two diagrams is correct! </li></ul>Please Note: The green chromosomes are identical to the red ones. #2 #1
  28. 28. Diagram #1 <ul><li>How many chromosomes are found in each cell in Diagram #1 on the previous slide? </li></ul><ul><li>Answer : Four – The new cells shown in Diagram #1 have only half the number of chromosomes of the original cell. </li></ul><ul><li>The new cells are called daughter cells. </li></ul><ul><li>The original cell is called the parent cell. </li></ul><ul><li>Diagram #1 shows two daughter cells with only half of the genes that were found in the parent cell. </li></ul>
  29. 29. Diagram #2 <ul><li>How many chromosomes are found in each new cell in Diagram #2 on the previous slide? </li></ul><ul><li>Answer : Eight – Diagram #2 shows that each daughter cell has the SAME number of chromosomes as the parent cell. </li></ul><ul><li>The new cells in Diagram #1 have lost chromosomes. </li></ul><ul><li>The chromosome number of the new cells in Diagram #2 is the same as the number in the parent (original) cell. </li></ul>
  30. 30. Mitosis <ul><li>Mitosis is the process that ensures the exact duplication of the chromosomes in the nucleus during cell division. </li></ul><ul><li>From this information, which diagram correctly shows mitosis? </li></ul><ul><li>Answer : Diagram #2 – This diagram shows that each daughter cell has the same number of chromosomes, and the same information, as the parent cell. </li></ul><ul><li>During mitosis, the daughter cells must receive the same information (genes on chromosomes) as the parent cell. </li></ul>
  31. 31. Replication <ul><li>How does a cell with four chromosomes give rise to two cells, each with four chromosomes? </li></ul><ul><li>Copies of the parent cell’s chromosomes are formed. </li></ul><ul><li>These exact copies then become part of the daughter cells. </li></ul><ul><li>The formation of exact copies of the parent cell’s chromosomes is an important step in mitosis! </li></ul><ul><li>It is called: REPLICATION . </li></ul>
  32. 32. Replication of Chromosomes: <ul><li>Keeps the chromosome number the same in each cell. </li></ul><ul><li>Ensures that the information found in the genes is the same within each cell of the organism. </li></ul><ul><li>Is an important step in the process of mitosis. </li></ul>
  33. 33. Review… <ul><li>Homologous chromosomes are pairs of chromosomes having genes (information) for the same traits. </li></ul><ul><li>Mitosis is a process that maintains the same number of chromosomes. </li></ul><ul><li>Replication is the formation of exact copies of the original chromosomes during the process of mitosis. </li></ul><ul><li>The parent cell is the original cell in cell division. </li></ul><ul><li>Daughter cells are the two new cells that result from the process of cell division. </li></ul>
  34. 34. Quiz: <ul><li>Fill in the blanks in the following passage. </li></ul><ul><li>Every species (type) of plant or animal has a characteristic chromosome __________ that is the same for all members of that species. The chromosomes replicate during the process of mitosis and are found in pairs. The pairs of chromosomes containing genes for the same traits are called ___________ chromosomes. They are passed on from the original _________ cell to the new _________ cells during the process of cell division. </li></ul>
  35. 35. Quiz Answers: <ul><li>Fill in the blanks in the following passage. </li></ul><ul><li>Every species (type) of plant or animal has a characteristic chromosome __________ that is the same for all members of that species. The chromosomes replicate during the process of mitosis and are found in pairs. The pairs of chromosomes containing genes for the same traits are called ___________ chromosomes. They are passed on from the original _________ cell to the new _________ cells during the process of cell division. </li></ul>number homologous parent daughter
  36. 36. Section Four Stages of Mitosis
  37. 37. Section Three Review… <ul><li>During mitosis , the chromosomes in the nucleus of the parent cell replicate into two identical sets . </li></ul><ul><li>Each chromosome is made of DNA , which controls all cell activities. </li></ul><ul><li>DNA also controls the transfer of traits from parent to offspring. </li></ul><ul><li>When a cell undergoes mitosis , the chromosomes in each daughter cell are exact copies of the parent cell. </li></ul><ul><li>Although you began as a single cell, mitosis has produced billions of cells of which you are composed. </li></ul><ul><li>Every body cell contains chromosomes that are identical to the original cell. </li></ul>
  38. 38. A Typical Animal Cell… Cell Membrane : It is made of protein, lipid and carbohydrate. It regulates the movement of materials into and out of the cell. Centrosome : It is involved in mitosis and usually is composed of a pair of centrioles that appear later in mitosis. (Not Pictured.) Nuclear Membrane : It regulates the transport of materials between the cytoplasm and the nucleus. Chromosomes : They are made of DNA and contain the hereditary (genetic) information of the organism. Nucleolus : This structure, found in the nucleus, is involved in the manufacture of protein. It disappears during mitosis . (Found in this area.)
  39. 39. Stages of Mitosis <ul><li>When a cell undergoes mitosis , it goes through five stages. </li></ul>Interphase Prophase Metaphase Anaphase Telophase
  40. 40. Five Stages of Mitosis During interphase , the chromosomes replicate (make exact copies of themselves). This is one of the most important parts of mitosis . The daughter cells eventually receive the same information as contained in the parent cell .
  41. 41. Five Stages of Mitosis During prophase , the centrosome divides into two centrioles . Fibers arise from the centrioles . These fibers are called astral rays . Fibers also appear between the two centrioles and become the spindle . The replicated chromosomes thicken and can easily be seen. The nucleolus disappears. The nuclear membrane disappears. The centrioles continue to move to opposite ends of the cell. The spindle forms from spindle fibers between the centrioles.
  42. 42. Five Stages of Mitosis During metaphase , the chromosomes begin to line up along the middle of the spindle. The imaginary center line of the spindle is called the equatorial plane . Notice that each chromosome is securely attached to its replicated partner by a small structure called a centromere (small dot between pairs). The centromere attaches each chromosome pair to the spindle fiber. The replicated chromosomes, held by the centromere, are called chromatids .
  43. 43. Five Stages of Mitosis Centromere Chromatids Notice that the pair of chromosomes ( red and yellow ) are exact copies of each other.
  44. 44. Five Stages of Mitosis During anaphase , the chromosome pairs separate and move to opposite poles (ends) of the cell. Notice that each pole has exactly the same chromosome pairs!
  45. 45. Five Stages of Mitosis During telophase , the chromosomes become thin and long, as they did in interphase . A new nuclear membrane forms. The nucleolus reappears. The final stage of mitosis occurs when the membrane pinches in. The two cells are called daughter cells . These cells are exact copies of the parent cell , and have the same information.
  46. 46. Five Stages of Mitosis <ul><li>Study the animated diagram below. Can you identify the five stages of mitosis? </li></ul>
  47. 47. Five Stages of Mitosis <ul><li>Finally, click on the link below to view an animated (Macromedia Flash) presentation of Mitosis. This will require a connection to the internet. This is an excellent resource – you can click on specific stages of mitosis or play the entire animation. It also shows you what an actual cell would look like in each stage. (Link should automatically open in a web browser.) </li></ul><ul><li>CellsAlive ! Mitosis </li></ul><ul><li>(Click on Link) </li></ul>
  48. 48. Review… <ul><li>Interphase </li></ul><ul><ul><li>The chromosomes replicate. </li></ul></ul><ul><ul><li>The centrioles begin to move apart. </li></ul></ul><ul><li>Prophase </li></ul><ul><ul><li>Chromosomes are visible and thick. </li></ul></ul><ul><ul><li>Nuclear membrane/nucleolus disappear. </li></ul></ul><ul><ul><li>Astral rays and spindle fibers form. </li></ul></ul><ul><li>Metaphase </li></ul><ul><ul><li>Chromosome pairs line up at midline. </li></ul></ul><ul><li>Anaphase </li></ul><ul><ul><li>Chromosome pairs separate and move to opposite poles. </li></ul></ul><ul><li>Telophase </li></ul><ul><ul><li>Nucleolus/nuclear membrane reappear. </li></ul></ul><ul><ul><li>Cell membrane pinches in. </li></ul></ul>
  49. 49. Plant Cells… <ul><li>Plant cells are similar to animal cells, with two exceptions: </li></ul><ul><ul><li>Plant cells have no centrosomes and do not form astral rays. </li></ul></ul><ul><ul><li>The plant membrane does not pinch in. A cell plate forms between the two daughter cells. By adding cellulose to the plate, a new cell wall is formed. </li></ul></ul>Onion Root Tip Mitosis: Telophase Anaphase Metaphase Prophase Interphase
  50. 50. Try These Questions: <ul><li>Select the letter of the correct answer from the list below: </li></ul><ul><li>The ________________ of chromosomes occurs during interphase. </li></ul><ul><li>A ________________ forms during the telophase of a plant cell. </li></ul><ul><li>During anaphase, the chromosomes move along the ______________ fibers. </li></ul><ul><li>Chromosomes line up along the equatorial plane during the ________________ stage. </li></ul>A. spindle D. metaphase B. centriole E. anaphase C. replication F. cell plate
  51. 51. Answers: <ul><li>The ________________ of chromosomes occurs during interphase. </li></ul><ul><li>A ________________ forms during the telophase of a plant cell. </li></ul><ul><li>During anaphase, the chromosomes move along the ______________ fibers. </li></ul><ul><li>Chromosomes line up along the equatorial plane during the ________________ stage. </li></ul>replication cell plate spindle metaphase
  52. 52. Section Five Testing Your Knowledge
  53. 53. This Is A Test of What You Have Learned… <ul><li>There are 10 questions on this test. </li></ul><ul><li>Try to correctly answer all of the questions. </li></ul><ul><li>If you miss a question, watch the screen for an explanation of the correct answer. </li></ul>
  54. 54. Select The Best Matching Choice: <ul><li>Chromosome: </li></ul>Correct Answer: G The chromosomes contain the genes that may be expressed as traits (characteristics) in the organism. The information (as genes) is arranged in a definite sequence along the chromosomes. <ul><li>Centromere: </li></ul>Correct Answer: B The centromere attaches the chromatids (chromosome pairs) to the spindle fibers during mitosis. The chromosomes then are drawn to opposite poles of the cell. <ul><li>Answer Column : </li></ul><ul><li>Found outside the cell </li></ul><ul><li>Attaches chromatids </li></ul><ul><li>Forms spindle fibers </li></ul><ul><li>In daughter cells only </li></ul><ul><li>In plant cells only </li></ul><ul><li>Formed by nucleolus </li></ul><ul><li>Contains genes </li></ul><ul><li>Unit of length </li></ul>
  55. 55. Select The Best Matching Choice: <ul><li>Centriole: </li></ul>Correct Answer: C The centriole is the cell structure that produces astral rays and spindle fibers. The chromosomes line up and travel along the spindle fibers during mitosis. Centrioles are produced by the centrosome. <ul><li>Micron: </li></ul>Correct Answer: H A micron is the unit of length most frequently used when describing cell size. Square microns are used for area, and cubic microns are used for volume. A micron equals one millionth of a meter. <ul><li>Answer Column : </li></ul><ul><li>Found outside the cell </li></ul><ul><li>Attaches chromatids </li></ul><ul><li>Forms spindle fibers </li></ul><ul><li>In daughter cells only </li></ul><ul><li>In plant cells only </li></ul><ul><li>Formed by nucleolus </li></ul><ul><li>Contains genes </li></ul><ul><li>Unit of length </li></ul>
  56. 56. Select The Best Choice To Complete Each Analogy: <ul><li>First is to last as interphase is to _______________. </li></ul><ul><li>A. prephase </li></ul><ul><li>B. prophase </li></ul><ul><li>C. telophase </li></ul><ul><li>D. metaphase </li></ul><ul><li>E. anaphase </li></ul>telophase Since interphase is the beginning of mitosis, it can be considered to be the first step. Telophase is the last step in this process.
  57. 57. Select The Best Choice To Complete Each Analogy: <ul><li>Word is to page as ____________ is to chromosome . </li></ul><ul><li>A. nucleus </li></ul><ul><li>B. nuclear membrane </li></ul><ul><li>C. centrosome </li></ul><ul><li>D. centromere </li></ul><ul><li>E. gene </li></ul>gene Since a word is a small piece of information that appears on a page , it is most like a gene (which also contains a small piece of information) on a chromosome .
  58. 58. Fill In The Blanks… As a cell grows, it increases its ________________ by increasing its cell membrane so that it may absorb more nutrients and get rid of more wastes. When a cell reaches its maximum size, it must ______________ by the process of ______________. Before the cell does this, it doubles the number of chromsomes during the process of ____________. surface area divide cell division mitosis
  59. 59. Cell Functions ~ Growth and Mitosis ~ Biology Basics Review! You Have Completed...
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