1. Cell Processes and Energy Photosynthesis Respiration Cell Division Cancer Table of Contents

2. 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.

3. 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.

4. Cell Processes and Energy 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. - Photosynthesis

5. Cell Processes and Energy End of Section: Photosynthesis

6. 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.

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

8. Cell Processes and Energy 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. Respiration is when an organism breathes in oxygen because oxygen is needed by cells. Respiration also means the process in which cells break down simple food molecules such as sugar and release the energy they contain. - Respiration What You Know What You Learned

9. Cell Processes and Energy Links on Cellular Respiration Click the SciLinks button for links on cellular respiration. - Respiration

10. Cell Processes and Energy End of Section: Respiration

11. 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.

12. Cell Processes and Energy - Cell Division The Cell Cycle

13. Cell Processes and Energy 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 Division

14. Cell Processes and Energy Length of the Cell Cycle The longest curved arrow represents the cell’s interphase; the shortest represents cytokinesis; and the middle one represents mitosis. Reading Graphs: What do the three curved arrows outside the circle represent? - Cell Division

15. Cell Processes and Energy Length of the Cell Cycle Interphase Reading Graphs: In what stage of the cell cycle is the wedge representing growth? - Cell Division

16. Cell Processes and Energy Length of the Cell Cycle 10 hours Interpreting Data: In human liver cells, how long does it take DNA replication to occur? - Cell Division

17. Cell Processes and Energy Length of the Cell Cycle Interphase Drawing Conclusions: In human liver cells, what stage in the cell cycle takes the longest time? - Cell Division

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

19. 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.

20. Cell Processes and Energy 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. The Cell Cycle Cell grows, makes a copy of DNA. Chromosomes and spindle fibers form; nuclear envelope breaks down. Chromosomes line up across the center and attach to a spindle fiber. Centromeres split; chromatids separate and move to opposite ends. Chromosomes stretch out; new nuclear envelope forms around chromosomes. Cell pinches in two; each daughter cell has same number of identical chromosomes. - Cell Division

21. Cell Processes and Energy End of Section: Cell Division

22. 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.

23. Cell Processes and Energy 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. 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. How Cancer Spreads - Cancer

24. Cell Processes and Energy Links on Cancer Click the SciLinks button for links on cancer. - Cancer

25. Cell Processes and Energy End of Section: Cancer

26. Cell Processes and Energy Graphic Organizer Comparing Photosynthesis and Respiration Feature Oxygen and sugars PhotosynthesisRespiration Raw materials Products Is energy released? Water and carbon dioxide Yes Oxygen and sugars Water and carbon dioxide No