1. Go to Section: Are All Cells Alike? All living things are made up of cells. Some organisms are composed of only one cell. Other organisms are made up of many cells. 1. What are the advantages of a one-celled organism? 2. What are the advantages of an organism that is made up of many cells? Section 7-1 Interest Grabber

2. Go to Section: 7-1 Life is Cellular Leeuwenhoek – invented the microscope; observed pond water Robert Hooke – first scientist to observe a cell. He used a compound light microscope to observe cork. Schleiden – stated that all plants are composed of cells. Schwann – stated that all animals are made of cells.

3. Go to Section: The Cell Theory All organisms are composed of one or more cells. The cell is the basic unit of structure and function in all living organisms. All cells come from preexisting cells.

4. Go to Section: Prokaryotes and Eukaryotes Prokaryotes – do not contain a nucleus; bacteria in the Monera kingdom. Eukaryotes – contain a nucleus; all other kingdoms.

5. Go to Section: Prokaryotic Cell Cell membrane Cytoplasm Nucleus Organelles Eukaryotic Cell Section 7-1 Prokaryotic and Eukaryotic Cells

6. Go to Section: 7-2 Eukaryotic Cell Structure nucleus (control center) - large dark structure; some unicellular organisms like bacteria do not have a nuclei. a. prokaryotes - lack a nucleus b. eukaryotes - contain a nucleus

7. Go to Section: The Nucleus The nucleus is the information center of the cell and contains DNA; directs all activities in a cell. It contains two membranes that form the nuclear envelope. Nuclear envelope contains dozens of pores for molecules to move in and out. Nucleolus - made of RNA and proteins; where ribosomes are made. chromosomes - DNA forms these in eukaryotic cells; they contain the genetic information that must be passed to each new generation of cells.

8. Go to Section: Ribosomes and Endoplasmic Reticulum ribosomes - structures where proteins are made. (composed of RNA and protein) endoplasmic reticulum - complex network of sacs that transport materials inside the cell; site of cellular chemical reactions a) smooth ER - special enzymes and chemicals may be stored here b) rough ER - responsible for the synthesis of proteins

9. Go to Section: Golgi Apparatus, Lysosomes, and Vacuoles Golgi apparatus - modifies, collects, packages, and distributes molecules in a cell. Lysosomes - small membrane bordered structures necessary for digesting certain materials in a cell. Vacuoles - store materials such as water, salts, proteins, and carbohydrates.

10. Go to Section: Mitochondria and Chloroplasts mitochondria and chloroplasts - change energy from one form to another. Mitochondria change chemical energy stored in food into compounds. Chloroplasts trap the energy of sunlight and convert to chemical energy; found only in plants and algae.

11. Go to Section: Cytoskeleton cytoskeleton - composed of a variety of filaments and fibers that support cell structure and drive cell movement. a) microtubules – thin, hollow cylinders made of protein; important in cell division by forming centrioles (animal cells); some contain cilia (short hairlike projections that help movement) and flagella (longer whiplike structures that help unicellular organisms move about) b) microfilaments - long thin fibers that function in the movement and support of the cell.

12. Go to Section: 7-3 Cell Boundaries cell membrane – the boundary between the cell and its environment. It allows the steady flow of nutrients to come into and out of the cell. cell wall - found in plants, algae, and some bacteria; The plasma membrane is surrounded by a cell wall. It helps to protect and support the cell. selective permeability – a process in which the cell membrane of a cell allows some molecules into the cell while keeping others out.

13. Go to Section: ProkaryotesEukaryotes Cell membrane Contain DNA Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Animal CellsPlant Cells Centrioles Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Section 7-2 Venn Diagrams

14. Go to Section: Plant Cell Nuclear envelope Ribosome (attached) Ribosome (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Section 7-2 Figure 7-5 Plant and Animal Cells

15. Go to Section: Animal Cell Centrioles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Smooth endoplasmic reticulum Mitochondrion Cell Membrane Ribosome (free) Ribosome (attached) Section 7-2 Figure 7-5 Plant and Animal Cells

16. Go to Section: Cell membrane Endoplasmic reticulum Microtubule Microfilament Ribosomes Mitochondrion Section 7-2 Figure 7-11 Cytoskeleton

17. Go to Section: In or Out? How is a window screen similar to a cell membrane? Read on to find out. 1. What are some things that can pass through a window screen? 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell? Section 7-3 Interest Grabber

18. Go to Section: Movement Into and Out of the Cell Diffusion – the movement of particles from an area of high concentration to an area of low concentration Osmosis – the diffusion of water across a selectively permeable membrane.

19. Go to Section: How Osmosis Works Isotonic solution – the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. (same strength) Hypotonic solution – the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell. Therefore, there is more water outside the cell than inside. This will cause the water to flow into the cell. (above strength) Hypertonic solution – the concentration of dissolved substances outside the cell is higher than the concentration inside the cell. Cells in the hypertonic solution experience osmosis that causes water to flow out. (below strength)

20. Go to Section: Section 7-3 Figure 7-15 Osmosis

21. Go to Section: Facilitated Diffusion The diffusion of particles across a membrane with the help of a carrier protein.

22. Go to Section: High Concentration Low Concentration Cell Membrane Glucose molecules Protein channel Section 7-3 Facilitated Diffusion

23. Go to Section: Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains Section 7-3 Figure 7-12 The Structure of the Cell Membrane

24. Go to Section: Passive and Active Transport Passive Transport – when the cells use no energy to move particles. (Diffusion, Osmosis, and Facilitated Diffusion) Facilitated diffusion is the transport of molecules across the membrane by transport proteins. Active Transport – movement of materials through a membrane against a concentration gradient. It requires energy from the cell.

25. Go to Section: Molecule to be carried Molecule being carried Energy Section 7-3 Figure 7-19 Active Transport

26. Go to Section: From Simple to More Complex Many multicellular organisms have structures called organs that have a specific function and work with other organs. Working together, these organs carry out the life processes of the entire organism. Section 7-4 Interest Grabber

27. Go to Section: 1. Some activities cannot be performed by only one person, but need a team of people. What type of activity requires a team of people to work together in order to complete a task? 2. What do you think are some characteristics of a successful team? 3. How is a multicellular organism similar to a successful team? Section 7-4 Interest Grabber continued

28. Go to Section: 7-4 The Diversity of Cellular Life Cell Specialization – the process where cells throughout an organism develop in different ways to perform different tasks. Cells  Tissues  Organs  Organ Systems

29. Go to Section: Muscle cellSmooth muscle tissueStomachDigestive system Section 7-4 Levels of Organization

30. Video Contents Videos Click a hyperlink to choose a video. Diffusion Osmosis Passive Transport Active Transport Endocytosis and Exocytosis

31. Video 1 Click the image to play the video segment. Video 1 Diffusion

32. Video 2 Click the image to play the video segment. Video 2 Osmosis

33. Video 3 Click the image to play the video segment. Video 3 Passive Transport

34. Video 4 Click the image to play the video segment. Video 4 Active Transport

35. Video 5 Click the image to play the video segment. Video 5 Endocytosis and Exocytosis

36. Internet The latest discoveries in cell study Cell structure activity Career links on histotechnologists Interactive test Articles on cells For links on cell theory, go to www.SciLinks.org and enter the Web Code as follows: cbn-3071.www.SciLinks.org For links on cell membranes, go to www.SciLinks.org and enter the Web Code as follows: cbn-3073.www.SciLinks.org Go Online

37. Section 1 Answers Interest Grabber Answers 1. What are the advantages of a one-celled organism? A one-celled organism has simpler needs and can respond immediately to its environment because its entire cell is immersed in its environment. 2. What are the advantages of an organism that is made up of many cells? In a multicellular organism, different jobs are divided among different groups of cells that work together. Also, a multicellular organism can continue to survive even if it loses some of its cells.

38. Section 2 Answers Interest Grabber Answers Working with a partner, answer the following questions. 1. What are some of the different parts of a computer? What are the functions of these computer parts? Answers may include: monitor (interfaces with the computer’s environment), software (instructions for how to carry out different jobs), CPU (directs the computer's activities), recycle bin or trash can (storage area for wastes), and so on. 2. How do the functions of these computer parts correspond to the functions of certain cell parts? Students should try to link the functions they described in question 1 to the functions of the different cell structures. The cell needs a way to interface with its environment (cell membrane), instructions for carrying out different jobs (DNA), and a CPU to direct the cell’s activities (nucleus).

39. Section 3 Answers Interest Grabber Answers 1. What are some things that can pass through a window screen? Answers may include air, fine dust, and rainwater. 2. What are some things that cannot pass through a window screen? Why is it important to keep these things from moving through the screen? Insects, leaves, and other matter that may fall from trees. The screen keeps out annoying insects and objects that may bring dirt into the home. 3. The cell is surrounded by a cell membrane, which regulates what enters and leaves the cell. Why is it important to regulate what moves into and out of a cell? Materials such as oxygen and food that are needed by the cell have to be able to get inside the cell. At the same time, excess materials have to leave the cell.

40. Section 4 Answers Interest Grabber Answers 1. Some activities cannot be performed by only one person, but need a team of people. What type of activity requires a team of people to work together in order to complete a task? Answers might include building a human pyramid or constructing an arch out of blocks. 2. What do you think are some characteristics of a successful team? Divide up jobs and cooperate well with one another. 3. How is a multicellular organism similar to a successful team? The functions of the organism are divided up among its parts (organs and organ systems). All the parts cooperate to carry out all the functions of the whole organism.

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