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CELLULAR STRUCTURE AND FUNCTION

CELLULAR STRUCTURE AND FUNCTION. BIG IDEA. Cells are the structural and functional units of all living organisms. Cell Discovery and Theory. Section 7.1. MAIN IDEA #1. The invention of the microscope led to the discovery of cells. Important Discoveries.

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CELLULAR STRUCTURE AND FUNCTION

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  1. CELLULAR STRUCTURE AND FUNCTION

  2. BIG IDEA • Cells are the structural and functional units of all living organisms.

  3. Cell Discovery and Theory • Section 7.1

  4. MAIN IDEA #1 • The invention of the microscope led to the discoveryof cells.

  5. Important Discoveries • Robert Hooke- observed cork with the first microscope and coined the term “cellulae” meaning small rooms • Anton van Leeuwenhoek- first to observe living organisms with a microscope • Both men led to many scientific discoveries (scientific revolution)

  6. Microscopes • Compound light microscope- uses visible light and a series of lenses to create a magnified image.

  7. Microscopes • Electron microscope- uses magnets to beamelectrons at thin specimens. • Only nonlivingcells and tissues can be observed with electron microscopes

  8. Cell Theory • One of the fundamental ideas of modern biology and includes the following three principles. • All living organisms are composed of one or more cells • Cells are the basic unit of structure and organization of all livingorganisms • Cells arise only from previously existing cells, with cells passingcopies of their genetic material on to their daughter cells

  9. Cell types • Prokaryotic- cells without a nucleusOR membrane bound organelles (mostly unicellular). • Eukaryotic- have a true nucleus and membrane bound organelles. • Both have plasma membranes!

  10. Eukaryotic structures • Nucleus- distinct central organelle that contains the cell’s genetic material in the form of DNA. • Organelles- enable specialized cell functions to take place in different parts of the cell at the same time. • Eukaryotes are thought to have evolvedfrom prokaryotes-Endosymbiont Theory

  11. The Plasma Membrane • Section 7.2

  12. MAIN IDEA #2 • The plasma membrane helps to maintain a cell’s homeostasis.

  13. Functions of the Plasma Membrane • Creates a thin, flexibleboundary that controls the movement of substances into and out of the cell • Selective permeability- capability to allow some substances pass through while keeping others out.

  14. Plasma Membrane • Phospholipid bilayer- phospholipids are arranged in a double layer, TAIL TO TAIL. • Phospholipids have a polarhead and two non-polar “tails.” • Creates the barrier that is polar at its surface and non-polar in the center. • Separates the inside and outside environments of the cell.

  15. THINK ABOUT IT!!! • How do hydrophobic substances cross a plasma membrane?

  16. Other membrane components • Transport proteins- move needed substances or wastes through the membrane. • Cholesterol- non-polar molecule among the phospholipids; keeps the “tails” from sticking together- fluidity • Carbohydrates (sugars)- help with cell identification

  17. Fluid Mosaic Model • Phospholipids can movesideways across the membrane • Other components can even move through/among the bilayer. • The fluidity of the membrane allows a scattered/random pattern arrangement of the components- mosaic.

  18. Structures and Organelles • Section 7.3

  19. MAIN IDEA #3 • Eukaryotic cells contain organelles that allow the specialization and the separation of functions within the cell.

  20. Cytoplasm • semifluid environment inside the plasma membrane. • In ALL cells • Prokaryotic- all chemical processes • Eukaryotic- processes take place inorganelles

  21. Cytoskeleton • Framework for the cell within the cytoplasm also aids in cell movement and other cellular activities. • ALL Eukaryotic cells • Microtubules- long, hollow protein cylinders • Microfilaments- thin protein threads.

  22. Cell Structures • Nucleus- control center of the cell that contains coded directions for the production of proteins and cell division. • Surrounded by a nuclear envelope • ALL Eukaryotic

  23. Cell Structures • Ribosomes- site of protein synthesis • Made of 2 components • Can be free floatingOR attached to the ER • Manufacturedby the nucleolus • ALL cells

  24. Cell Structures • Endoplasmic reticulum- highly folded membrane that is the site of protein and lipid synthesis • ALL Eukaryotic • Smooth- does NOT have ribosomes attached • Rough- HAS ribosomes associated within

  25. Cell Structures • Golgi apparatus- a flattened stack of tubular membranes that modifies proteins and packages them for distribution outside the cell • ALL Eukaryotic • Vesicles= packages; fuses with plasma membrane

  26. Cell Structures • Vacuoles- a membrane- bound vesicle for the temporary storage of materials • Plant cells- ONE large • Animal cells- a FEW small

  27. Cell Structures • Lysosomes- a vesicle that contains digestive enzymes for the breakdown of excess or worn-out cellular substances. • Animal cells ONLY

  28. Cell Structures • Centrioles- organelles that occur in pairs and are important for cell division • Animal cells • MOST protist

  29. Cell Structures • Mitochondria- a membrane-bound organelle that makes energy available to the rest of the cell. • ALL Eukaryotic cells

  30. Cell Structures • Chloroplasts- a double-membrane organelle with thylakoids containing chlorophyll where photosynthesis takes place. • Plant cells ONLY

  31. Cell Structures • Cell wall- an inflexiblebarrier that provides support and protects the plant cell. • Plant cells • Fungi cells • SOME Prokaryotes

  32. Cell Structures • Cilia and flagella- projections from cell surfaces that aid in locomotion and feeding. • Cilia- tiny hairs; SOME animal cells, protists cells, and Prokaryotes • Flagella- tail like; SOME animal cells, Prokaryotes, and some plant cells

  33. Cellular Transport • Section 7.4

  34. MAIN IDEA #4 • Cellular transportmoves substancesWITHIN the cell and moves substances INTO & OUT of the cell.

  35. Diffusion • The netmovement of particles from an area of high concentration to low concentration. • Dynamic equilibrium- condition, in which there is continuous movement but NO overall change

  36. Diffusion • Factors that affect diffusion rate • Concentration • Temperature • Pressure Ex: more collision= faster diffusion • Diffusion does NOT require any energy!

  37. Facilitated Diffusion • Uses transport proteins to move other ions and small molecules across the plasma membrane. • Still from high concentration to low concentration!

  38. Osmosis • Diffusion of water across a selectively permeable membrane. • Also exhibits dynamic equilibrium

  39. Isotonic • Cell is in a solution that has the same concentration of water and solutes. • Stable/Equilibrium

  40. Hypotonic • Cell is in a solution that has a lower concentration of solute. • Net movement of water INTO the cell

  41. Hypertonic • The concentration of the solute outside of the cell is higher than inside. • Net movement of water is OUT of the cell

  42. Active Transport • The net movement of particles against a concentration gradient. • Requires energy • Maintains homeostasis

  43. Na+/K+ Pump • Uses ATP energy to transport three sodium ions out of the cell while moving two potassium ions into the cell. + + +

  44. Large Particles • Endocytosis- intake of a substance • Exocytosis- secretion of a substance

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