2. 1 Biology A VIEW OF THE CELL Chapter 7

3. 2 THE DISCOVERY OF CELLS Microscopic units that make up all living things Cells are alive They are the smallest unit that can carry out all the processes of life

4. 3 Robert Hooke 1665 English 1st person to observe cells under the microscope he looked at dead cork cells.

5. 4 Anton van Leeuwenhoek 1600’s Dutch 1st person to observe living cells

6. 5 Matthias Schleiden 1900s German botanist stated that all plants are made of one or more cells

7. 6 Theodore Schwann 1900s German zoologist stated that all animals are made of one or more cells

8. 7 Rudolf Virchow 1900s German cytologist stated that cells come only from pre-existing cells

9. 8 Robert Brown Discovered the central part or nucleus of the cell

10. 9 Cell Theory All living things are made of cells. Cells are the basic units of structure and function in living things. All cells come from other cells.

11. 10 Cell Diversity Cells are limited in Size Cell volume increases more rapidly than cell surface area The cell needs nutrients, oxygen, and other molecules to carry out life processes At some point the surface area is not large enough to allow molecules to enter at a rate fast enough.

12. 11 Cell Diversity Cell Shape Variety of shapes Diversity of forms Internal Organization Organelles A cell component that performs specific functions for the cell.

13. 12 Cell Diversity Eukaryotic Cells Cells that contain a membrane nucleus and organelles. Prokaryotic Cells Unicellular organisms that lack a membrane bound nucleus or organelles.

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15. 14 Parts of the Eukaryotic Cell Cell Membrane: Regulates what enters or leaves the cell Acts as a barrier Gives the cell shape Holds the cytoplasm

16. 15 Parts of the Eukaryotic Cell Cell membranes are selectively permeable. Some substances are allowed to pass into and out of the cell and other substances are not allowed. The structure of the cell membrane depends on the functions the cell performs.

17. 16 Parts of the Eukaryotic Cell Cell membranes are made of lipids PAGE 183 Phospholipids- form a lipid bilayer Polar head-points outward  Attracted to water Non-polar tails (2)points inward  Hydrophobic moves away from water Steroids (lipid) fit between the tails of the phospholipids. Animal cell steroids are cholesterol.

18. 17 Parts of the Eukaryotic Cell Cell membrane proteins Proteins Some have carbohydrates attached to them  Hold adjoining cells together or act as attachment sites. Act as mechanisms for transporting molecules through the lipid bilayer

19. 18 Parts of the Eukaryotic Cell Cell Membrane Fluid Mosaic Model The lipid bilayer acts like a liquid It can move and change

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21. 20 Parts of the Eukaryotic Cell Organelles Cytoplasm Contains organelles Clear, jellylike material  Cytosol  Mostly water  Contains dissolved salts, minerals and organic molecules. Between the cell and the nucleus

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23. 22 Parts of the Eukaryotic Cell Mitochondria Rod shaped consist of a smooth outer membrane acts as a boundary between the mitochondria and the cytosol cristae a folded inner membrane increases surface area provides more space for chemical reactions to take place

24. 23 Parts of the Eukaryotic Cell Mitochondria Sites of chemical reactions that transfer energy from organic compounds to ATP (energy). More numerous in cells that have a large energy requirement. Have their own DNA. New mitochondria are made when existing mitochondria grow and divide.

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27. 26 Parts of the Eukaryotic Cell Ribosomes Not surrounded by a membrane Consist of a protein and RNA Sites of protein synthesis Protein factories some attach to the endoplasmic reticulum (rough E R) others remain free in the cytosol

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29. 28 Parts of the Eukaryotic Cell Endoplasmic Reticulum (ER) A system of membranous tubules and sacs Inside is a network of canals Cell’s internal transport system molecules use it to travel from one area of the cell to another.

30. 29 Parts of the Eukaryotic Cell Rough Endoplasmic Reticulum (ER) has ribosomes attached to it cells that make large amounts of proteins have more rough ER

31. 30 Parts of the Eukaryotic Cell Smooth ER not covered in ribosomes involved in the synthesis of steroids in gland cells. Regulation of calcium levels in muscle cells break down of toxic substances by liver cells Rough and Smooth ER may be continuous with each other

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33. 32 Parts of the Eukaryotic Cell Golgi Bodies Processing, packaging, and secreting organelle A system of membranes that appear as a series of flattened sacs with a characteristic convex shape. Modifies proteins for export by the cell

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35. 34 Parts of the Eukaryotic Cell Lysosomes Small, spherical organelles that contain digestive enzymes. Can digest proteins, carbohydrates, lipids, DNA, RNA, viruses, bacteria, and old organelles. Play a role in separating parts; like fingers in early development. Common in animals, fungi, and protist, rare in plants

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37. 36 Parts of the Eukaryotic Cell Cytoskeleton a network of long protein strands located in the cytosol not surrounded by membranes provides support participates in movement of organelles in the cytosol

38. 37 Parts of the Eukaryotic Cell Two major components of the cytoskeleton Microfilaments threads made of protein called actin, which are linked together to form a polymer chain. Smallest strands contribute to cell movement play a role in the contraction of muscle cells.

39. 38 Parts of the Eukaryotic Cell Two major components of the cytoskeleton cont. Microtubules hollow tubes largest strands extend outwards from a central point near the nucleus come together and form spindle fibers when the cell is ready to divide

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41. 40 Parts of the Eukaryotic Cell Cilia and Flagella hair-like organelles, that extend from the surface of the cell made of microtubules Cilia short, present in large numbers used to sweep food in to the cell, propel debre away from an area, or to move. Flagella long, in less numbers, mostly single used for movement

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43. 42 Parts of the Eukaryotic Cell Nucleus: nuclear matrix for maintaining shape protein skeleton Control Center contains fine strands of chromatin which is a combination of DNA and protein. Forms chromosome when cells are ready to divide Site where RNA is copied.

44. 43 Parts of the Eukaryotic Cell Nuclear Envelope double membrane that surrounds the nucleus Separates it from the rest of the cell Nuclear pores openings that allow certain materials (RNA, Ribosomes)to move into and out of the nucleus.

45. 44 Parts of the Eukaryotic Cell Nucleolus Small body inside the nucleus synthesizes and partially assembles the ribosomes.

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48. 47 Parts of the Eukaryotic Cell Plant Cell 3 additional structures #1 Cell Walls  Thick outer covering outside the cell membrane  Protection and support  Found in plants, algae, fungi, and some bacteria

49. 48 Parts of the Eukaryotic Cell Cell Wall Cont.  Primary cell walls  during formation  located outside of the cell membrane  enlarges as the cell grows  Secondary cell walls  forms when cell has reached full size  develops between the primary cell wall and the cell membrane  tough and woody

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51. 50 Cell Parts and Their Jobs #2Vacuoles Liquid filled space Stores water, waste, and food Storage tank In plant cells the vacuoles are large, they help support the plant

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53. 52 Parts of the Eukaryotic Cell # 3 Plastids organelles surrounded by two membranes contains DNA store starch, fat, or pigments Chloroplast  contain green pigments  type of plastids that encloses a system of flattened sacs called thylakoids  where energy from the sun is converted into chemical energy in organic compounds.  Photosythesis- takes place in the thylakoids

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55. 54 Cell Parts and Their Jobs Centrioles Found in animal cells not plant cells Located near the nucleus Exist in pairs Help with cell reproduction

56. 55 Special Cell Processes Cells need substances to stay alive. Examples are food and oxygen

57. 56 Special Cell Processes Diffusion The process in which molecules move from an area of high concentration to an area of low concentration. This process continues and an equilibrium is reached.

58. 57 Special Cell Processes Osmosis Diffusion of water across a membrane. Water molecules continue to move and an equilibrium inside and outside is reached.

59. 58 Special Cell Processes Turgor pressure The pressure within the plant cell due to water filling the large vacuole. It is the chief means of support in nonwoody plants. Plamolysis The loss of turgor pressure (due to the loss of water) causes plants to wilt.

60. 59 Special Cell Processes Organization in multicellular organisms. Cells form tissues Tissues are groups of similar cells that work together to carry out a specific job.

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62. 61 Special Cell Processes Organization in multicellular organisms. Tissues form organs A group of tissues work together to do a job. Organs form organ systems A group of organs work together to do a certain job

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64. 63 Special Cell Processes Organization in multicellular organisms. Organ systems work together to make up an organism. Cells  tissues  organs  organ systems  organisms

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