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					Cell Processes and Energy

Table of Contents
Photosynthesis


Respiration


Cell Division


Cancer
Cell Processes and Energy - Photosynthesis

                      Sources of Energy
   Nearly all living things obtain energy either directly or
   indirectly from the energy of sunlight captured during
   photosynthesis.
Cell Processes and Energy - Photosynthesis

         The Two Stages of Photosynthesis
                During photosynthesis, plants and some other
                organisms use energy from the sun to convert
                carbon dioxide and water into oxygen and sugars.
Cell Processes and Energy - Photosynthesis


                          Sequencing
   Sequence is the order in which the steps in a process occur.
   As you read, create a flowchart that shows the steps in
   photosynthesis. Put each step in a separate box in the
   flowchart in the order in which it occurs.

                     Steps in Photosynthesis

                          Sunlight strikes leaf.


                   Chlorophyll captures light energy.

               Cells use the energy to produce sugars and
                 oxygen from water and carbon dioxide.
Cell Processes and Energy




         End of Section:
         Photosynthesis
Cell Processes and Energy - Respiration

                Two Stages of Respiration
    During respiration, cells break down simple food molecules
    such as sugar and release the energy they contain.
Cell Processes and Energy - Respiration

            Photosynthesis and Respiration
    You can think of photosynthesis and respiration as opposite
    processes.
Cell Processes and Energy - Respiration


                   Using Prior Knowledge
    Your prior knowledge is what you already know before you
    read about a topic. Before you read, write a definition of
    respiration in a graphic organizer like the one below. As you
    read, revise your definition based on what you learn.

                            What You Know
          Respiration is when an organism breathes in oxygen
          because oxygen is needed by cells.

                           What You Learned
          Respiration also means the process in which cells
          break down simple food molecules such as sugar and
          release the energy they contain.
Cell Processes and Energy - Respiration

              Links on Cellular Respiration




      Click the SciLinks button for links on cellular respiration.
Cell Processes and Energy




          End of Section:
           Respiration
Cell Processes and Energy - Cell Division

                              Mitosis
    During mitosis, the cell’s nucleus divides into two new nuclei.
    One copy of the DNA is distributed into each of the two
    daughter cells.
Cell Processes and Energy - Cell Division

                      The Cell Cycle
Cell Processes and Energy - Cell Division


                Length of the Cell Cycle
                               How long does it take for a cell
                               to go through one cell cycle? It
                               all depends on the cell. A human
                               liver cell, for example, completes
                               one cell cycle in about 22 hours,
                               as shown in the graph. Study the
                               graph and then answer the
                               following questions.
Cell Processes and Energy - Cell Division


                Length of the Cell Cycle
                               Reading Graphs:

                                 What do the three curved
                                 arrows outside the circle
                                 represent?


                                 The longest curved arrow
                                 represents the cell’s
                                 interphase; the shortest
                                 represents cytokinesis; and
                                 the middle one represents
                                 mitosis.
Cell Processes and Energy - Cell Division


                Length of the Cell Cycle
                               Reading Graphs:

                                 In what stage of the cell cycle
                                 is the wedge representing
                                 growth?


                                 Interphase
Cell Processes and Energy - Cell Division


                Length of the Cell Cycle
                               Interpreting Data:

                                 In human liver cells, how long
                                 does it take DNA replication
                                 to occur?


                                 10 hours
Cell Processes and Energy - Cell Division


                Length of the Cell Cycle
                               Drawing Conclusions:

                                 In human liver cells, what
                                 stage in the cell cycle takes
                                 the longest time?


                                 Interphase
Cell Processes and Energy - Cell Division

                      Structure of DNA
    The DNA molecule is shaped like a twisted
    ladder.
Cell Processes and Energy - Cell Division

                     Replication of DNA
    Because of the way in which the nitrogen bases pair with one
    another, the order of the bases in each new DNA molecule
    exactly matches the order in the original DNA molecule.
Cell Processes and Energy - Cell Division


                                 Sequencing
     As you read, make a cycle diagram that shows the events in
     the cell cycle, including the phases of mitosis. Write each
     even in a separate circle.
                                  Cell grows, makes a
                                     copy of DNA.

   Cell pinches in two; each                              Chromosomes and spindle
daughter cell has same number                                fibers form; nuclear
  of identical chromosomes.       The Cell Cycle           envelope breaks down.



  Chromosomes stretch out;                                  Chromosomes line up
 new nuclear envelope forms                                 across the center and
   around chromosomes.                                     attach to a spindle fiber.
                                   Centromeres split;
                                chromatids separate and
                                 move to opposite ends.
Cell Processes and Energy




          End of Section:
           Cell Division
Cell Processes and Energy - Cancer

                      What Is Cancer?
   Cancer is a disease in which cells grow and divide
   uncontrollably, damaging the parts of the body around them.
Cell Processes and Energy - Cancer


                       Previewing Visuals
   When you preview, you look ahead at the material to be
   read. Preview Figure 17. Then write two questions you have
   about the illustrations in a graphic organizer like the one
   below. As you read, answer your questions.
                          How Cancer Spreads
       Q. What is a tumor?

       A. A mass of abnormal cells that develops when cancerous cells
          divide and grow uncontrollably.
       Q. How does cancer spread?

       A. Some of the tumor cells can break off and enter the
          bloodstream.
Cell Processes and Energy - Cancer

                     Links on Cancer




          Click the SciLinks button for links on cancer.
Cell Processes and Energy




          End of Section:
             Cancer
Cell Processes and Energy

                       Graphic Organizer
            Comparing Photosynthesis and Respiration

 Feature                Photosynthesis      Respiration


                        Water and carbon
 Raw materials                              Oxygen and sugars
                        dioxide

                                            Water and carbon
 Products               Oxygen and sugars
                                            dioxide


 Is energy released?    No                  Yes

				
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posted:9/10/2012
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