Bio Chapter 7

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keemia_shariati
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43622
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Bio Chapter 7
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2010-10-20 22:21:58
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Biology
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Biology Chapter 7: Cell Structure & Function
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  1. What are the functions of the cell membrane?
    • Regulates what enters & leaves the cell
    • Provides protection & support
  2. What is a lipid bilayer?
    • Double-layered sheet
    • The core of nearly all cell membranes
  3. What is the difference in the functions of the proteins & the carbohydrates attached to a cell membrane?
    Some of the proteins form channels & pumps that help to move material across the cell membrane. Many of the carbohydrates act like chemical identification cards, allowing cells to identify one another.
  4. In what organisms are cell walls found?
    Cell walls are found in many organisms, including plants, algae, fungi, and nearly all prokaryotes.
  5. True or False: The cell wall lies inside the cell membrane.
    FALSE! It lies outside of the cell membrane.
  6. What is the main function of the cell wall?
    Provide support & protection for the cell
  7. What are plant cells mostly made of?
    fibers of carbohydrates & protein
  8. What is the concentration of a solution?
    The mass of a solute in a given volume of solution (mass/volume)
  9. What is diffusion?
    • The process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
    • Examples: drops of food coloring in water, open perfume bottle in room, etc.
  10. What it meant when a system has reached equilibrium?
    The concentration of the substance on both sides of the membrane will be the same.
  11. What does it mean that biological membranes are selectively permeable?
    It means that some substances can pass across them, while others cannot.
  12. What is osmosis?
    The diffusion of water through a selectively permeable membrane
  13. True or False: Water tends to diffuse from a region where it is less concentrated to a region where it is highly concentrated.
    FALSE! Water tens to diffuse from a region where it is highly concentrated to a region where it is less concentrated.
  14. When will water stop moving across a membrane?
    When equilibrium is reached
  15. What is an isotonic solution?
    • Concentration of solute outside the cell is equal to the concentration inside the cell
    • Water diffuses in & out of the cell at an equal rate
    • Two solutions are isotonic if the solutions are the same strength
  16. What is a hypertonic solution?
    • Concentration of solute outside the cell is greater than inside the cell
    • Water diffuses out of the cell
    • A solution is hypertonic if the solution is above strength in solute
  17. What is a hypotonic solution?
    • Concentration of solute inside the cell is greater than outside the cell
    • Water diffuses out of the cell
    • A solution is hypotonic if the solution is below strength in solute
  18. On which side of a selectively permeable membrane does osmosis exert a pressure?
    Exerts a pressure known as osmotic pressure on the hypertonic side
  19. What happens during the process of facilitated diffusion?
    Molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
  20. What is the role of protein channels in the cell membrane?
    Allow particular substances to cross different membranes
  21. True or False: Facilitated diffusion does not require the cell to use energy.
    TRUE!
  22. What is active transport?
    The energy-requiring process that moves material across a cell membrane against a concentration difference
  23. True or False: Active transport always requires transport proteins during the process.
    FALSE! It requires energy.
  24. What are the 3 types of active transport?
    • Endocytosis
    • Phagocytosis
    • Exocytosis
  25. What is endocytosis?
    Process by which a cell takes materials into the cell by infolding of the cell membrane
  26. What is phagocytosis?
    Process by which extensions of cytoplasm surround & engulf large particles & take them into the cell
  27. What is exocytosis?
    Process by which a cell releases large amounts of materials
  28. During endocytosis, what happens to the pocket in the cell membrane when it breaks loose from the membrane?
    It forms a vacuole within the cytoplasm.
  29. What is a unicellular organism?
    A single-celled organism
  30. What is cell specialization in a multicellular organism?
    The process by which cells develop in different ways to perform different tasks
  31. What are 4 levels of organization in a multicellular organism?
    • Individual cells
    • Tissues
    • Organs
    • Organ systems
  32. What is a tissue?
    A group of similar cells that perform a particular function
  33. What are the 4 main types of tissue in most animals?
    • Muscle
    • Epithelial
    • Nervous
    • Connective
  34. What is an organ?
    A group of tissues that work together to perform a specific function
  35. What kinds of tissues can be found within a muscle in your body?
    There is much more than muscle tissue. There are nervous tissues & connective tissues (each type of tissue performs an essential task to help the organ function).
  36. What is an organ system?
    A group of organs that work together to perform a specific function
  37. What is a cell?
    The structure that makes up every living thing
  38. What was Anton van Leeuwenhoek one of the first to see in the 1600s?
    Tiny living organisms (cells) through the microscope
  39. What did a thin slice of cork seem like to Robert Hooke when he observed it through a microscope?
    It seemed to be made up of thousands of tiny, empty chambers he called "cells"
  40. What did the German botanist Matthias Schleiden conclude?
    All plants were made of cells
  41. What did the German biologist Theodor Schwann conclude?
    All animals were made of cells
  42. How did Rudolph Virchow summarize his years of work?
    • Concluded that new cells could be produced only from the division of existing cells
    • Summarized his years of work in the cell theory
  43. What are the 3 concepts that make up the cell theory?
    • 1) All living things are composed of cells
    • 2) Cells are the basic unit of structure & function in living things
    • 3) New cells are produced from existing cells
  44. Why are electron microscopes capable of revealing details much smaller than those seen through light microscopes?
    Because the wavelengths of electrons are much smaller than those of light
  45. What are prokaryotes?
    • Organisms whose cells lack nuclei
    • Example: bacteria
    • They grow & reproduce
    • They have cell membranes & cytoplasm
  46. What are eukaryotes?
    • Organisms whose cells contain nuclei
    • Generally larger & more complex than prokaryotic cells
    • Have defined chromosomes & nucleus
    • Contain membrane bound organelles
    • Have a definite nucleus & nuclear membrane
  47. What is an organelle?
    A specialized structure that performs important cellular functions within a eukaryotic cell ("little organs")
  48. What do animal cells contain?
    • nucleus
    • nucleolus
    • nuclear envelope
    • centrioles
    • mitochondria
    • cell membrane
    • golgi apparatus
    • rough ER
    • smooth ER
    • lysosomes
  49. What do plant cells contain?
    • cell wall
    • cell membrane
    • nucleus
    • nucleolus
    • nuclear envelope
    • chloroplast
    • golgi apparatus
    • mitochondria
    • vacuole
    • rough ER
    • smooth ER
  50. What is the function of the nucleus?
    • The control center of the cell
    • Controls most cell processes
    • Contains the hereditary information of DNA
    • Contains nearly all the cell's DNA & with it the coded instructions for making proteins and other important molecules
  51. What important molecules does the nucleus contain?
    Nucleolus, chromatin, nuclear envelope, nuclear pores
  52. What is chromatin?
    The granular material visible within the nucleus
  53. What does chromatin consist of?
    DNA bound to protein
  54. What are chromosomes?
    Threadlike structures within the nucleus containing the genetic information that is passed from one generation of cells to the next
  55. What is the nucleolus?
    Small, dense region contained in most nuclei
  56. What occurs in the nucleolus?
    It's where the assembly of ribosomes begins
  57. What is the nuclear envelope?
    The layer of 2 membranes that surrounds the nucleus of the cell
  58. What are ribosomes?
    • Small particles in the cell on which proteins are assembled
    • Made of DNA & protein
  59. What is the difference between rough ER & smooth ER?
    The difference is that ribosomes are found on the surface of rough ER, whereas on smooth ER it's not.
  60. What is the role of the Golgi apparatus in the cell?
    • The function is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.
    • The finishing touches are put on proteins before they are ready to leave the factory.
    • Stack of membranes in which enzymes attach carbohydrates and lipids to protein
  61. What are lysosomes?
    • Filled with enzymes used to break down food into particles that can be used
    • Break out organelles that have outlived their usefulness
    • Also break down lipids, carbohydrates, and proteins
  62. What are vacuoles?
    Cell organelles that store materials such as water, salts, proteins, and carbohydrates
  63. What is the role of the central vacuole in plants?
    Filled with liquid, the central vacuole's pressure in plant cells make it possible for plants to support heavy structures such as leaves & flowers
  64. How does the contractile vacuole in a paramecium help maintain homeostatis?
    By contracting rhythmically, the contractile vacuole pumps excess water out of the cell (the control of water content)
  65. True or False: Both choloroplasts & mitochondria are enclosed by two membranes.
    TRUE!
  66. In what do choroplasts and mitochondria contain their own genetic information?
    Small DNA molecules
  67. What are mitochondria?
    Organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use
  68. Are mitochondria found in plant cells, animal cells, or both?
    BOTH!!!
  69. Where are chloroplasts found?
    In plants & some other organisms (where photosynthesis occurs)
  70. Biologist Lynn Margulis has suggested that mitochondria and chloroplasts are descendants of what kind of organism?
    Bacteria!!!
  71. What is the cytoskeleton?
    The network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement
  72. What are microtubes?
    • Description: hollow structures made up of proteins known as tubulins
    • Functions: maintain cell shape, help build cilia & flagella, form centrioles in cell division
  73. What are microfilaments?
    • Description: threadlike structures made of a protein called actin
    • Functions: support the cell, helps cells move
  74. What are chloroplasts?
    Uses energy from sunlight to make energy-rich food
  75. What's a vacuole?
    Saclike structure that stores materials
  76. What are endoplasmic reticulum?
    An internal membrane system in which components of cell membrane and some proteins are constructed

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