biology exam 2

  1. magnification
    ratio of an object's image size to its real size
  2. light microscope (LM)
    • -most common microscope in the lab
    • -visible light is passed through the specimen and then through the glass lenses
  3. resolution
    measure of the clarity of the image
  4. electron microscope
    • magnification 100,000x
    • electron beam in a vaccum focused by magnets
    • electron beam has much shorter wavelength than visible light
  5. Scanning electron microscope (SEM)
    • provides for detailed studies of the surface of a specimen
    • thing getting studied often covered in gold
  6. transmission electron microscope (TEM)
    study of intermal ultrastructure of cells
  7. cell fractionation
    • uses centrifuge
    • takes cells apart and separates the major organelles and other subcellular structures from one another
    • forms pellets on the bottom
    • most dense pellet out first
  8. plasma membrane
    selective barrier that bounds and protects all cells
  9. Where does cellular respiration occur?
  10. Where is ATP produced?
  11. What organelle is responsible for photosynthesis?
  12. chloroplast
    • plant cell
    • photosynthetic organelle
    • converts energy of sunlight to chemical energy stored in sugar molecules
  13. plasmodesmata
    • plant cells
    • channels through cell walls that connect the cytoplasms of adjacent cells
  14. central vacuole
    • plant cells
    • prominent organelle in older plant cells
    • functions include storage, breakdown of waste products, hydrolysis of macromolecules
    • enlargement of vacuole is a major mechanism of plant growth
  15. lysosome
    • membranous sac that animal uses to digest molecules
    • acidic environment
    • recycles cell's organic molecules
  16. mitochondrion
    • plant and animal cells
    • organelle where cellular respiration occurs and ATP is generated
  17. golgi apparatus
    • plant and animal cells
    • products of ER are modified and stored and then sent to other destinations
    • consist of cisternae-flattened membranous sacs resembling stacks of pita bread
    • two poles of stack are called cis face and trans face
  18. flagellum
    • animal cell
    • locomotion organelle present in some animal cells
    • composed of a cluster of microtubules within an extension of the plasma membrane
  19. gap junction
    a type of intercellular junction in animals that allows the passage of materials between cells
  20. contrast
    accentuates differences in parts of the sample
  21. Ribosome
    • complexes made of ribosomal RNA and protein
    • carry out protein synthesis
    • free or bound
  22. What are the components of the endomembrane system?
    nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and the plasma membrane
  23. endoplasmic reticulum (ER)
    • network of membranous tubules and sacs called cisternae
    • separates internal compartment of the ER from the cytosol
    • smooth and rough
  24. smooth ER
    • metabolic processes: synthesis of lipids, metabolism of carbs, detox of drugs and poisons
    • stores calcium ions
  25. rough ER
    • makes secretory proteins
    • grows in place by adding membrane proteins and phospholipids to its own membrane
    • have ribosomes attached
  26. thylakoid
    flattened, interconnected sacs in the chloroplast
  27. granum
    individual stack of thylakoids
  28. stroma
    • fluid outside the thylakoids
    • contains chloroplast DNA and ribosomes as well as many enzymes
  29. cytoskeleton
    • network of fibers extending throughout the cytoplasm
    • made up of microtubules, microfilaments, and intermediate filaments
    • support, mobility, and regulation
  30. microtubules
    • thickest of the three components of the cytoskeleton
    • wall of this tube is filled with tubulin
    • shape and support the cell
    • serve as tracks along which organelles equipped with motor proteins can move
    • can separate chromosomes during cell division
  31. microfilaments
    • built from molecules of actin
    • present in all eukaryotic cells
    • cell motility
  32. intermediate filaments
    • more permanent fixtures of cells than microfilaments and microtubules
    • functions as the framework of the entire cytoskeleton
  33. cell wall
    • extracellular structure of plant cell
    • protects plant cell, maintains its shape, and prevents excessive uptake of water
  34. amphipathic
    • hydrophilic region and hydrophobic region
    • most proteins within membranes are amphipathic
  35. fluid mosaic model
    the membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a bilayer of phospholipids
  36. desmosome
    fasten cells together into strong sheets
  37. tight junction
    • plasma membrane of neighboring cells are very tightly pressed against each other, bound together by specific proteins
    • prevent leakage of extracellular fluid across a layer of epithelial cells
  38. What are the most abundant lipids in most membranes?
  39. What are the two major types of membrane proteins?
    Integral and peripheral
  40. integral proteins
    penetrate hydrophobic core of lipid bilayer
  41. peripheral proteins
    appendages lossely bound to the surface of the membrane, often exposed to parts of integral proteins
  42. channel proteins
    hydrophobic channel that certain molecules or atomic ions use as a tunnel through the membrane
  43. diffusion
    • movement of molecules of any substance so that they spread out evenly into the available space
    • more concentration to less concentration
  44. passive transport
    • diffusion of a substance across a biological membrane
    • cell doesnt have to expend energy ot make it happen
  45. osmosis
    diffusion of water across a selectively permeable membrane
  46. tonicity
    the ability of a solution to cause a cell to gain or lose water
  47. isotonic
    • same environment for the cell and its environment
    • no net movement of water acorss the plasma membrane
    • water flows at the same rate in both directions
    • volume of cell is stable
  48. hypertonic
    • water will lose water to environment
    • shrivel and die
  49. hypotonic
    • water will enter cell faster than it leaves
    • cell will swell and burst
  50. turgid
    swollen or distended as in plant cells (A walled cell becomes turgid if it has a greater solute concentration than its surroundings, resulting in entry of water)
  51. flaccid
    • limp
    • plant cell becomes flaccid when the cells and surroundings are isotonic
    • no tendency for water to enter
  52. facilitated diffusion
    the spontaneous passage of molecules or ions across a biological membrane with the assistance of specific transmembrane transport proteins
  53. What are the two types of transport proteins?
    • channel proteins
    • carrier proteins
  54. channel proteins
    provide corridors that allow a specific molecule or ion to cross the membrane
Card Set
biology exam 2
biology exam