Chapter 4

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Chapter 4
2013-02-22 20:04:07
Key Terms Questions

Cell Structure & Function
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  1. Cell Theory
    Theory that all organisms consist of one or more cells, which are the basic unit of life; all cells come from division of pre-existing cells; and all cells pass hereditary material to offspring
  2. Cytoplasm
    Semifluid substance enclosed by a cell's plasma membrane
  3. Nucleus
    Organelle with two membranes that hold's a eukaryotic cell's DNA
  4. Plasma Membrane
    A cell's outermost membrane
  5. Surface to volume ratio
    A relationship in which the volume of an object increases with the cube of the diameter, and the surface area increases with the square
  6. Biofilm
    Community of microorganisms living within a shared mass of slime
  7. Cell wall
    Semirigid but permeable structure that surrounds the plasma membrane of some cells
  8. Flagellum
    Long, slender cellular structure used for motility
  9. Nucleoid
    Region of cytoplasm where the DNA is concentrated inside a bacterium or archaeon
  10. Pilus
    Protein filament that projects from the surface of some bacteria and archaea
  11. Plasmid
    Small circle of DNA in some bacteria and archaea
  12. Ribosome
    Organelle of protein synthesis
  13. Chromatin
    Collective term for DNA molecules together with their associated proteins
  14. Chromosome
    A structure that consists of DNA and associated proteins; carries part or all of a cell's genetic information
  15. Nuclear Envelope
    A double membrane that constitutes the outer boundary of the nucleus. Pores in the membrane control which substances can cross
  16. Nucleolus
    In a cell nucleus, a dense, irregularly shaped region where ribosomal subunits are assembled
  17. Nucleoplasm
    Viscous fluid enclosed by the nuclear envelope
  18. Central Vacuole
    Fluid filled vesicle in many plant cells
  19. Endomembrane System
    Series of interacting organelles (endoplasmic reticulum, Golgi bodies, vesicles) between nucleus and plasma membrane; produces lipids, proteins
  20. Endoplasmic Reticulum (ER)
    Organelle that is a continuous system of sacs and tubes; extension of the nuclear envelope. Smooth ER makes lipids and breaks down carbohydrates and fatty acids; rough ER modifies polypeptides made by ribosomes on its surface
  21. Golgi Body
    Organelle that modifies polypeptides and lipids; also sorts and packages the finished products into vesicles
  22. Lysosome
    Enzyme-filled vesicle that functions in intracellular digestion
  23. Peroxisome
    Enzyme-filled vesicle that breaks down amino acids, fatty acids, and toxic substances
  24. Vacuole
    A fluid-filled organelle that isolates or disposes of waste, debris, or toxic materials
  25. Vesicle
    Small, membrane-enclosed, saclike organelle; different kinds store, transport, or degrade their contents
  26. Chloroplast
    Organelle of photosynthesis in the cells of plants and many protists
  27. Mitochondria
    Organelle that produces ATP by aerobic respiration in eukaryotes
  28. Plastid
    Category of double-membraned organelle in plants and algal cells. Different types specialize in storage or photosynthesis - chloroplast, amyloplast
  29. Basal Body
    Organelle that develops from a centriole
  30. Cell Cortex
    Reinforcing mesh of cytoskeletal elements under a plasma membrane
  31. Centriole
    Barrel-shaped organelle from which microtubules grow
  32. Cilium
    Short, movable structure that projects from the plasma membrane of some eukaryotic cells
  33. Cytoskeleton
    Dynamic framework of protein filaments that support, organize, and move eukaryotic cells and their internal structures
  34. Intermediate Filament
    Stable cytoskeletal element that structurally supports cells and tissues

    Intermediate filaments strengthen and maintain the shape of animal cells and tissues.
  35. Microfilament
    Reinforcing cytoskeletal element; a fiber of actin subunits

    Networks of microfilaments reinforce the surfaces of eukaryotic cells
  36. Microtubule
    Cytoskeletal element involved in cellular movement; hollow filament of tubulin subunits

    Microtubules organize eukaryotic cells and help move their parts.
  37. Motor Protein
    Type of energy-using protein that interacts with cytoskeletal elements to move the cell's parts or the whole cell
  38. Pseudopod
    A temporary protrusion that helps some eukaryotic cells move and engulf prey
  39. Adhering Junction
    Cell junction composed of adhesion proteins; anchors cells to each other and extracellular matrix
  40. Cell Junction
    Structure that connects a cell to another cell or to extracellular matrix
  41. Cuticle
    Secreted covering at a body surface
  42. Extracellular Matrix (ECM)
    Complex mixture of cell secretions; supports cells and tissues; has roles in cell signaling
  43. Gap Junction
    Cell junction that forms a channel across the plasma membranes of adjoining animal cells
  44. Lignin
    Material that stiffens cell walls of vascular plants
  45. Plasmodesmata
    Cell junctions that connect the cytoplasm of adjacent plant cells
  46. Primary Wall
    The first cell wall of young plant cells
  47. Secondary Wall
    Lignin-reinforced wall that forms inside the primary wall of a plant cell
  48. Tight Junctions
    Arrays of fibrous proteins; join epithelial cells and collectively prevent fluids from leaking betweeen them
  49. What are the differences between the prokaryotic & eukaryotic cells?
    Every cell has a plasma membrane, cytoplasm, and DNA. Only eukaryotic cells have a nucleus.
  50. Why are cells so small?
    Cells are so small due to the surface to volume ratio. A living cell must exchange substances with its environment at a rate that keeps pace with its metabolism. If the cell gets too large, the inward flow of nutrients and the outward flow of wastes across the plasma membrane will not be fast enough to keep the cell alive.
  51. What are the 4 statements of cell theory?
    • Every living organism consists of one or more cells.
    • The cell is the structural and functional unit of all organisms. A cell is the smallest unit of life, individually alive even as part of a multicelled organism. 
    • All living cells arise by division or preexisting cells.
    • Cells contain hereditary material, which they pass to their offspring during division. 
  52. What are the features of a prokaryotic cell? Be able to define and describe each component. 
    • Cell wall - a durable cell wall surrounding the plasma membrane. Archaean cell walls consist of proteins, bacterial cell walls consist of a polymer of peptides and polysaccharides. 
    • Flagellum - long, slender cellular structures used for motion
    • Pili - protein filaments that project from the surface and help the cells cling to or move across surfaces, also help in reproduction
    • Ribosomes - organelles upon which polypeptides are assembled
    • Nucleoid - an irregularly shapd region of cytoplasm that houses the DNA
    • Plasmids - small circles of DNA that carry genes that provide advantages like resistance to antibiotics
  53. What are the differences between archaea and bacteria?
    • Archaea and bacteria are different in structure and metabolism.
    • Most archaean cell walls consist of proteins
    • Most bacterial cell walls consist of a polymer of peptides and polysaccaharides
  54. Components of Eukaryotic Cells
    • Organelles with Membranes:
    • Nucleus 
    • Endoplasmic Reticulum (ER)
    • Golgi Body
    • Vesicles
    • Mitochondrian
    • Chloroplast
    • Lsysome
    • Peroxisome
    • Vacuole

    • Organelles without Membranes:
    • Ribosomes
    • Centriole
    • Cytoskeleten
  55. Components of Eukaryotic Cells - Nucleus
    protects & controls access to DNA
  56. Components of Eukaryotic Cells - ER
    routing, modifying new polypeptide chains; synthesizing lipids
  57. Components of Eukaryotic Cells - Golgi Body
    modifying new polypeptide chains; sorting, shipping proteins and lipids
  58. Components of Eukaryotic Cells - Vesicles
    transporting, storing or digesting substances in a cell
  59. Components of Eukaryotic Cells - Mitochondrian
    Making ATP by glucose breakdown
  60. Components of Eukaryotic Cells - Chloroplast
    Photosynthesis in plants, some protists
  61. Components of Eukaryotic Cells - Lysosome
    intracellular digestion
  62. Components of Eukaryotic Cells - peroxisome
    inactivating toxins
  63. Components of Eukaryotic Cells - Lysosome
    • Prokaryotes:
    • no nucleus
    • capsule + cell wall + plasma membrane
    • no organelles
    • flagellum, ability to move
    • smaller
    • DNA organized in circular

    • Eukaryotes:
    • Nucleus
    • Cell Membrane (lipid bilayer)
    • Organelles
    • Larger
    • DNA organized in chromosomes
  64. Components of Eukaryotic Cells - vacuole
  65. Components of Eukaryotic Cells - ribosomes
    assembling polypeptide chaines
  66. Components of Eukaryotic Cells - centriole
    anchor for cytoskeleton
  67. Components of Eukaryotic Cells - cytoskeleton
    contributes to cell shape, internal organization, movement
  68. What are the similarities between eukaryotic and prokaryotic cells?
    • Both have:
    • DNA
    • Ribosomes
    • Cytoplasm
  69. What are some defining characteristics of the eukaryotic cells?
    All eukaryotic cells start life with a nucleus and other membrane-enclosed organelles
  70. List some differences between the animal cell and the plant cell:
    Animal cells have no cell wall, chloroplast, or vacuole
  71. Components of the Nucleus
    • Nuclear envelope
    • Nucleoplasm
    • Nucleolus
    • Chromatin
    • Chromosome
  72. Components of the Nucleus - Nuclear Envelope
    pore-riddled double membrane that controls which substances enter and leave the nucleus
  73. Components of the Nucleus - Nucleoplasm
    semifluid interior portion of the nucleus
  74. Components of the Nucleus - Nucleolus
    rounded mass of proteins and copies of genes for ribosomal RNA used to construct ribosomal subunits
  75. Components of the Nucleus - Chromatins
    total collection of all DNA molecules and associated proteins in the nucleus; all of the cell's chromosomes
  76. Components of the Nucleus - Chromosome
    one DNA molecule and many proteins associated with it
  77. What is the function of a nuclear pore?
    the nuclear pore controls what leaves and enters the nucleus, it acts as a gateway
  78. What is a nuclear envelope?
    the nuclear envelope is two lipid bilayers pressed together as a single membrane surrounding the nucleus, the outer bilayer is continuous with ER, and the nuclear pore allows certain substances to pass through the membrane, it requires an energy source