Micro ch3

  1. Light microscopes
    • Type of microscopes which use visible light for observing objects
    • Visible light passes through a specimen and then through a series of lenses to produce magnified image
    • Can magnify up to 1000x, making it relatively easy to observe cell size, shape and motility
    • Relatively ease to use, considerably less expensive than electron & atomic force
    • Also called compound microscope
  2. condenser lens
    • positioned btwn light source and specimen
    • does not affect magnification
    • focuses light on specimen
  3. resolving power
    • the min distance btwn 2 points at which those points can still be observed as separate objects
    • Max resolving of best light microscope is 0.2 μm, or 200 nm
  4. refraction
    bending of light rays
  5. refractive index
    a measure of the relative speed of light as it passes through the medium
  6. wet mount
    • used when preparing a live specimen
    • a drop of liquid on which a coverslip has been placed
  7. Types of light microscopes
    • Bright-field
    • Dark-field
    • Phase-contrast
    • Differential interference contrast
    • Fluorescence
    • Scanning laser
  8. Bright-field microscope
    • most common type of light microscope
    • Illuminates the field of view evenly
  9. Dark-field microscope
    • Cells stand out as bright objects against dark background
    • Light is directed toward the specimen at an angle
    • Makes unstained cells easier to see
    • *Used to see Treponema pallidum, which causes syphilis; as bright field will not work cause cells are too thin and stain poorly
  10. Phase-contrast microscope
    • Makes cells and other dense material appear darker
    • Increases contrast by amplifying differences in refractive index
    • Makes unstained cells easier to see
  11. Differential interference contrast microscope
    • DIC
    • Two light beams pass through the specimen and then recombine
    • Image of specimen appears 3D
  12. Fluorescence microscope
    • Used to observe cells or other materials that are either naturally fluorescent or stained or tagged with fluorescent dyes
    • Projects ultraviolet light, causing fluorescent molecules in the specimen to emit longer wavelength light
    • Used to observe cells stained or tagged with a fluorescent dye
  13. Scanning laser microscope
    • SLM
    • Used to construct a 3D image of structure
    • Provides detailed sectional and interior views of intact cell
    • Mirrors scan laser beam across successive regions and planes of a specimen
    • With that info, computer constructs image
  14. Confocal microscopy
    • Type of scanning laser microscope
    • Is like a CAT scan for cells
  15. Multiphoton microscopy
    • Similar to confocal microscope, but lower energy light is used
    • This light is less damaging to cells, so time-lapse images of live cells can be obtained. 
    • Light also penetrates deeper, making it possible to get interior views of relatively thick structures
  16. Electron microscope
    • can magnify in excess of 100,000x
    • Electron beams are used in place of visible light to produce the magnified image
    • Includes:
    • Transmission
    • Scanning
    • Drawback: All lenses and specimen must be in vacuum, otherwise molecules in air would interfer with electrons
  17. Transmission electron microscope
    • TEM
    • used to observe fine details of cell structure
    • Transmits beam of electrons through specimen
    • Elabroate specimen preparation is required
  18. cryo-electron microscopy
    • cryo-EM
    • a newer method of preparing and observing specimens with an electron microscope
    • involves rapidly freezing the specimen at very low temps, avoiding some of the simple preparation processes that damage cells
  19. Scanning electron microscopes
    • SEM
    • Used to observe surface details of cells
    • A beam of electrons scans back and forth over the surface of a specimen coated with thin film of metal
    • Produces 3D effect
  20. Atomic force microscope
    • Major advancement in 1980's
    • Produces images of individual atoms on a surface
    • A probe moves in response to even the slightest force btwn in and the sample
    • Produces a map showing the bumps and valleys of the atoms on the surface of the sample
  21. How do stains work?
    • Staining procedures typically use basic dyes, meaning the dyes carry a positive charge
    • The dyes stain cells because they are attracted to the many negatively charged cellular components
    • Most bacteria is negatively charged
  22. Simple stains
    • A basic dye is used to stain cells
    • Easy way to increase the contrast btwn otherwise colorless cells and transparent background
  23. negative staining
    • a procedure that colors the background
    • uses acidic dyes, which DOES NOT stain cells
    • As the cells repel the negatively charged dye, it allows the colorless cell to stand out against the background
  24. Differential stains
    • A multistep procedure used to stain cells and distinguish one group of microorganisms from another
    • Two most frequently used techniques are gram stain and acid-fast stain
  25. Gram stain
    • Used to separate bacteria into two major groups: Gram neg and Gram pos
    • The staining characteristics of these groups reflect a fundamental difference in the chemical structure of their cell walls
    • By far the most widely used staining procedure
  26. What is the order of stains for the gram stain
    • Crystal violet - primary stain which stains cells purple
    • Iodine - mordant, which fixes stain into the cell. Cells remain purple
    • Alcohol - Decolorizer, Gram-pos cells remain purple, Gram-neg become colorless
    • Safranin - counterstain, Gram-pos stays purple, Gram-neg appear pink
  27. Acid-fast stain
    Used to detect organism that do not easily take up stains, such as members of the genus Mycobacterium which cause TB and Hansen's disease (leprosy)

    Primary stain is red, counterstain is Methylene blue
  28. Capsule stain
    • Are often negative stains that take advantage of the fact the viscous capsules do not take up certain stains
    • In one common method, India ink is added to a suspension of cells to make a wet mount. The fine particles of ink darken background and allow the capsule to stand out as a clear area surrounding the cell
  29. Endospore stain
    • Needed for members of certain genera, including Bacillus and Clostridium, as they form endospores which are resistant to stain
    • Don't stain with the Gram, but can be seen as clear, smooth objects within stained cells
    • Uses Malachite green as primary stain
  30. Flagella Stain
    • Usually, flagella are too thin to be seen with light microscope
    • This stain uses a substance that allows staining agent to adhere to and coat thin flagella, making them visible using light microscopy
  31. Fluorescent Dyes and Tags
    • Fluorescent dyes and tags absorb ultraviolet light and then emit light of a longer wavelength
    • They are used in conjunction with a fluorescence microscope
  32. Fluorescent dyes
    • Some fluorescent dyes bind to compounds found in all cells
    • Others bind to compounds specific to only certain types of cells
  33. Fluorescent tags
    Antibodies to which a fluorescent molecule has been attached are used to tag specific molecules
  34. Immunofluorescence
    • A technique used to tag specific proteins with a fluorescent compound
    • can be used to detect organism
  35. Shapes of Common Bacteria
    • Coccus - round balls (cocks)
    • Rod - Duh
    • Bacillus - rod-shaped
    • Coccobacillus - rod shaped so short it may be mistaken for coccus
    • Vibrio - short, curved rod.., or vibrater
    • Spirillum - curved rod long enough to form smooth spirals
    • Spirochete - long, crimped, slinky thing
  36. Pleomorphic
    • Pleo means many; morphic refers to shape
    • When bacteria characteristically vary in their shape
  37. Diplococci
    • cocci that occur in pairs & often stick together
    • (binary fission)
  38. Typical cell groupings
    Cell adhering to one another following division form characteristic arrangements:

    • Chains:Cells divide in one plane. long line 
    • Packets : Cells divide in two or more planes perpendicular to one another
    • Clusters: Cells divide in several planes at random
  39. What are the surface layers of a prokaryotic cell?
    What is inside?
    • Called the cell envelope:
    • cytoplasmic membrane
    • cell wall
    • if present, the capsule (bacteria have capsules, but archaea rarely do)
    • Inside are the contents of the cell - the cytoplasm and nucleoid
  40. Cytoplasm
    • the viscous material enclosed in the envelope
    • fluid portion is called cytosol
  41. Nucleoid
    • The gelatinous region where the genetic material resides
    • NOT enclosed by a membrane
  42. Filamentous appendages
    • Extracellular structure composed of protein subunits that form a helical chain
    • Includes:
    • Flagella
    • Pili
  43. Flagella
    • Long protein structures
    • Provide the most common mechanism of mobility
    • Has 3 basic parts:
    • Filament-extends into external environment
    • Hook- flexible, curved segment connects filament to cell surface
    • Basal body - anchors structure to cell wall and cytoplasmic membrane
  44. Peritrichous
    • an arrangement of flagella in which they are distributed over the entire surface
    • Ex: E coli
  45. Polar flagellum
    a single flagellum at one end of the cell
  46. Chemotaxis
    • a phenomenon in which motile bacteria can sense the presence of chemicals or oxygen and respond by moving in a certain direction
    • If a nutrient, may serve as attracting and cell move toward it
    • If toxic, may act as repellent and cause cell to move away
  47. Pili
    • Considerably shorter and thinner than flagella
    • Different types of pili have different functions
    • Common types, often called fimbriae, allow cells to adhere to surfaces
    • A few types are used for twitching or gliding motility
    • Sex pili join cells in preparation for DNA transfer
  48. Capsules and slime layers
    • Extracellular layers outside the cell wall
    • Usually made of polysaccharide and referred to as glycocalyx
    • colonies that form either often appear moist and glistening
    • Some allow cells to adhere to specific surfaces, including teeth, rocks... and can then grow as biofilm
  49. Capsule
    • Distinct and gelatinous
    • Allows bacteria to adhere to specific surfaces
    • Allows some organisms to envade innate defense systems and thus cause disease
  50. Slime layer
    • Diffuse and irregular
    • Allows bacteria to adhere to specific surfaces
  51. Cell wall
    • Peptidoglycan provides rigidity to bacterial cell walls, preventing the cells from lysing
    • Gram-pos has thick layer of peptidoglycan that contains teichoic acids and lipoteichoic acids
    • Gram-neg has thin layer of peptidoglycan surrounded by an outer membrane. The outer layer of the outer membrane is lipopolysaccharide
  52. DNA; what does it include
    • Intracellular - duh
    • Includes:
    • Chromosomal: Carries genetic info required by cell. Typically single, circular, double-stranded DNA molecule
    • Plasmid: Extrachromosomal DNA molecule; generally carries only genetic info that may be advantageous to cell in certain situations
  53. Endospore
    • Type of dormant cell
    • Generally extraordinarily resistant to heat, desiccation ,UV light, and toxic chemicals
    • Can germinate, or exit dormant stage, and become a typical multiplying cell, called vegetative cell

    Ex: Bacillus and Clostridium
  54. Sporulation
    • endospore formation
    • a complex sequence of changes that begin when spore-forming bacteria experience limiting amts of carbon or nitrogen
    • 8 hr process begins with DNA duplication & septum divides cell asymmetrically 
    • Larger part engulfs smaller, making forespore within mother cell
    • Ultimately, mother cell is degraded & endospore is released
  55. germination
    • exiting the endospore stage
    • can be triggered by a brief exposure to heat or certain chemicals
    • takes on water and swells
    • Spore coat & cortex crack open, vegetative cell grows out
  56. Cytoskeleton
    Involved in cell division and control of cell shape
  57. Gas vesicles
    • Intracellular structure produced by some aquatic bacteria
    • Small rigid structures that provide buoyancy to a cell
    • Gases, not water, flow freely into the vesicles, thereby decreasing the density of the cell
    • By regulating the number of gas vesicles, a cell can float or sink to it's ideal position in the water column
  58. Storage Granules
    • Intracellular accumulations of high-molecular-weight polymers
    • Synthesized from a nutrient that a cell has in relative excess
  59. Ribosomes
    • Intracellular structure
    • Involved in protein synthesis, serve as structures that facilitate joining of amino acids
    • Relative size and density is expressed as distinct unit S (which reflects how fast they settle when spun at very high speeds in ultracentrifuge)
    • Two subunits, 30S and 50S, join to form the 70S ribosome, which is important as antibiotics that interfere with function of 70S ribosome have no effect on 80S molecule (which is eukaryotic)
  60. Cytoplasmic membrane
    • A thin, delicate structure that surrounds the cytoplasm and defines the boundary of the cell
    • It's a phospholipid bilayer embedded with proteins
    • Is selectively permeable
    • Also transmits info about external environment to inside of cell
  61. Fluid mosaic model
    Refers to the membrane proteins not being stationary; rather, they constantly drift in the lipid bilayer
  62. selectively permeable
    • Only certain substances can cross (referring to the cytoplasmic membrane)
    • Those that pass freely include gases such as:
    • Oxygen
    • Carbon dioxide
    • Nitrogen
    • Small hydrophobic molecules and water
  63. Aquaporins
    pore forming membrane proteins that specifically allow water molecules to pass through cytoplasmic membranes more easily
  64. Simple diffusion
    • Method by which molecules that can pass through the lipid bilayer move in and out of the cell
    • The molecules move from a region of high concentration to a region of low concentration, until equilibrium is reached.
    • Speed and direction depends on relative concentration on each side - the greater the difference in concentration the higher the rate of diffusion
  65. Osmosis
    • The diffusion of water across a selectively permeable membrane
    • Occurs when concentrations of solute (dissolved molecules and ions) on 2 sides of membrane are unequal
    • Typical of diffusion, water moves down its concentration gradient from high water concentration (low solute concentration) to low water concentration (high solute concentration)
    • *wants everything diluted and equal
  66. Three terms used to describe osmosis and opposing sides of a membrane:
    Hypotonic: hypo means less; tonic means solute

    Hypertonic: hyper means more

    Isotonic : iso means the same

    • Water flows from the hypotonic solution to the hypertonic one
    • No net water movement occurs btwn isotonic solutions
  67. Electron transport chain
    • a series of protein complexes of most prokaryotes which act as part of their energy-transforming processes
    • Transfers electrons and moves protons in and out of the cell
    • The expulsion of protons creates a proton gradient across cell membrane: + charged protons concentrated outside membrane, whereas neg charged hydroxyl ions remain inside
    • Because charged ions attract each other, stay close to membrane
  68. Proton motive force
    • Analogous to the energy stored in a battery
    • Refers to the electrochemical gradient created across the membrane from the separation of protons (+ charge) and hydroxyl ions (- charge) resulting from electron transport chain
    • Energy can be harvested when protons are allowed to move back into cell
  69. Transport systems
    • mechanisms that allow nutrients and other small molecules to enter the cells
    • Also used to expel wastes and compounds such as antibiotics and disinfectants that otherwise damage the cell
    • Transported molecules enter/exit through transport proteins
  70. Facilitated Diffusion
    • A form of passive transport, does not require energy
    • Uses transport protein to move substance from one side to the other by using concentration gradient to move molecules
    • *can only eliminate gradient, not create one, so molecules are transported until their concentration is the same on both sides
    • **Cause prokaryotes typically grow in nutrient-poor environment, generally rarely use to take in nutrients
  71. Active transport
    • moves compounds against a concentration gradient and uses energy
    • 2 main mechanisms use different forms of energy:
    • Proton Motive Force
    • ATP
  72. Transport system using proton motive force
    As a proton is allowed into the cell, another substance is simultaneously brought along or expelled
  73. Transport system using ATP
    • Transport mechanisms called ABC (ATP Binding-Cassette)
    • ATP is used as energy source
    • This system uses specific binding proteins that reside immediately outside the membrane to gather & deliver molecules to respective transport complexes
  74. Group translocation
    • a transport process that chemically alters a molecule during it's passage through the cytoplasmic membrane
    • typically done by adding a phosphate group, a process called phosphorylation

    Ex: glucose and several other sugars are phosphorylated during their transport
  75. secretion
    • a process by which cells actively move certain proteins they synthesize out of the cell
    • Some of the molecules must be moved to outside of cell as they will become enzymes that will break down macromolecules into their individual subunits
    • The macromolecules are too large to transport into cell, but subunits are not
    • Others makes up external structures such as flagella
  76. signal sequence
    • a characteristic sequence of amino acids, typically at one end of the molecule, that's destined for secretion
    • functions as a tag that directs the secretion machinery to move the preprotein across membrane
  77. Peptidoglycan
    • a material found only in bacteria
    • gives strength to Gram+ and Gram- bacterial cell walls
    • Basic structure is alternating series of 2 major subunits: N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG)
  78. Gram-Positive Cell Wall
    • Stains purple
    • Has thick layer of Peptidoglycan, which is permeable to sugars, amino acids + others
    • Also has teichoic acids, which are neg charged atoms
    • Has gel like layer btwn cytoplasmic m & peptidoglycan & teichoic acid 
    • No outer membrane
    • No lipopolysaccharide (endotoxin)
    • No porin proteins (unnecessary as no outer membrane)
    • Generally more susceptible to penicillin (with notable exceptions)
    • Sensitive to lysozyme
  79. Gram positive examples
    • Bacillus
    • Staphylococcus
    • Streptococcus
  80. Gram neg
    • Stains pink
    • Thin Peptidgolycan 
    • No Teichoic acid
    • Has outer membrane & lipopolysaccharide (endotoxin)
    • Has porin proteins, which allow molecules to pass through outer membrane
    • Generally less susceptible to penicillin
    • Not sensitive to lysozyme
  81. Gram neg example
    • Escherichia
    • Neisseria
    • Pseudomonas
  82. LPS
    • lipopolysaccharide
    • Makes up the bilayer structure of outer membrane in gram neg cell walls (instead of phospholipid)
    • When injected in animal, sx are like infection by live bacteria
    • Considered endotoxin
  83. endotoxin
    • Lipopolysaccharide, component of outer membrane of gram-neg cells that can cause sx such as fever and shock
    • lipid A is responsible for the effects
  84. 2 parts of LPS molecule
    Lipid A: anchors LPS in lipid bilayer, portion body recognized as sign of invading gram-neg bacteria

    O antigen: portion of LPS directed away from membrane, at opposite lipid A. Is chain of sugar... looks like fingers or shaggy carpet.
  85. Porins
    • specialized channel forming proteins that span the outer membrane of gram-neg bacteria
    • small molecules and ions use to cross membrane
    • Some are specific, others allow different molecules to cross
  86. Periplasm
    • A gel like substance with fills a region between the cytoplasmic membrane and the outer membrane (that space is called the periplasmic space)
    • All exported proteins accumulate here, unless specifically moved across outer membrane
    • Thus, filled with proteins
  87. How antibacterial substances affect peptidglycan
    • Interferes with synthesis or alters its structural integrity by weakening the molecule to a point where it can no longer prevent cell from bursting
    • No effect on eukaryotic cells as peptidoglycan is unique to bacteria
  88. Penicillin
    • most thoroughly studied antibiotic that interferes with pep synthesis
    • functions by preventing cross-linking of adjacent glycan chains
    • Far more effective on Gram-pos than Gram neg due to gram-neg outer membrane
  89. Lysozyme
    • an enzyme found in tears, saliva, and many other body fluids
    • attacks protective walls of bacteria by breaking the bonds that link the alternating subunits of glycan chain
    • destroys structural integrity of peptidoglycan molecule
  90. Why gram+ keeps crystal violet, not gram-
    • It's inside of cell, not wall, that is stained
    • Gram+ retains dye cause cell walls prevents crystal violet-iodine complex from being washed out by decolorizing agent
    • Gram- cells lose dye quite easily. Decolorizing agent thought to dehydrate thick layer of peptidoglycan, wall then acts as permeability barrier & prevents dye from leaving cell
  91. What bacteria naturally lack cell wall
    • Mycoplasma - causes mild form of pneumonia
    • has extremely variable shape as they lack rigid cell wall
    • Neither penicillin nor lysozyme affects these organisms
    • Mycoplasma & related bacteria can survive w/o cell wall cause cytoplasmic membrane has sterols in it, making it stronger than most other bacteria
  92. Cells walls of Archaea
    • Have a variety of cell wall types
    • None have peptidoglycan, but some have similar molecule called pseudopeptidoglycan
  93. Plasma membrane
    • Typical eukaryotic cell structure
    • Phospholipid bilayer embedded with proteins; however layer that faces cytoplasm differs significantly from side that faces outside
    • Permeability barrier, transport, and cell-to-cell communication
  94. Receptors
    • (Eukaryotic)
    • Membrane proteins that face the outside 
    • A given receptor binds a specific molecule, referred to as its ligand
    • Relationship allows cells to communicate with each other
  95. Transport proteins in eukaryotic cells
    • function as either carriers or channels
    • Carriers are analogous to proteins in prokaryotic cells that function in facilitated diffusion and active transport
    • Channels form small pores in membrane that allow only specific ions to diffuse through
  96. Endocytosis
    process by which a eukaryotic cell takes up material from surrounding environment by forming invagination (inward folds) in its membrane
  97. endosome
    • membrane-bound compartment formed from endocytosis
    • fuses to digestive organelles called lysosomes to form endolysosome
  98. Pinocytosis
    • Type of endocytosis
    • cell takes in liquids
  99. Receptor-mediated endocytosis
    • Variation of pinocytosis
    • Allows cell to take up extracellular ligands that bind to cells surface
  100. Phagocytosis
    • type of endocytosis used by phagocytes and protozoa
    • Cell sends out armlike extensions called pseudopods, which surround and enclose extracellular material into the cell in an enclosed compartment called a phagosome
    • This fuses with endosomes, and ultimately fuses with lysosomes to form phagolysosome
  101. Exocytosis
    • reverse of endocytosis
    • membrane-bound exocytic vesicles inside the cell fuse with the plasma membrane and release their contents to the outside
  102. Secretion in eukaryotic cells
    • As in prokaryotic, proteins destined for secretion have signal sequence, a characteristic amino acid that functions as tag
    • When ribosomes synthesize protein with sequence, they attach to complex on membrane of endoplasmic reticulum
    • Once inside ER, can easily be transported by vesicles to outside of cell
    • Proteins destined for various organelles also have specific amino acid tags
  103. Ribosome in eukaryotic
    • Involved in protein synthesis
    • is 80S, made up of 60S and 40S
  104. Cytoskeleton in eukaryotic cells
    • forms framework of cell
    • 3 components: 
    • actin filaments
    • microtubules
    • intermediate filaments
  105. Active filaments
    • allow cell cytoplasm to move
    • filaments rapidly assemble and subsequently disassemble to cause motion
  106. Microtubules
    • the thickest of the cytoskeleton components
    • long hollow structures made of protein subunits called tubulin
    • Form mitotic spindles
    • main structure that make up cilia and flagella
    • *antifungal drug griseofulvin interferes with action of microtubules in some fungi
  107. Intermediate filaments
    • function like ropes, strengthening the cell mechanically
    • by providing mechanical support, they allow cells to resist physical stresses
  108. Cilia
    • shorter than flagella
    • often covering a cell and moving in synchrony
    • Can either propel cell or move material along a stationary cell
  109. Flagella and cilia in eukaryotic cells
    • appear to project out of the cell yet are covered by extensions of the plasma membrane
    • composed of long microtubules grouped in 9+2 arrangement = nine pairs or microtubules surrounded by 2 individual ones
  110. nucleus
    • duh-contains genetic info in eukaryotic cell
    • boundary is two lipid bilayer membrane
    • complex protein structures span envelope, forming nuclear pores, allowing large molecules such as ribosomal subunits and proteins to be transported into and out of nucleus
    • *Nucleolus is region where ribosomal RNA is synthesized
  111. Mitochondria
    • function as ATP-generating powerhouses, are found in nearly all eukaryotic cells
    • complex structures bounded by two lipid bilayers- the outer and inner membranes
    • Outer is smooth, inner is highly folded, forming invaginations called cristae

    • Folds increase membrane's surface area
    • *Mitochondrial matrix contains DNA, ribosomes, etc necessary for protein synthesis. However, ribosomes are 70S rather than 80S as ribosome found in cytoplasm of eukaryotic cells
  112. Endosymbiotic therory
    • Mitochondrial matrix contains DNA, ribosomes, etc necessary for protein synthesis. However, ribosomes are 70S rather than 80S as ribosome found in cytoplasm of eukaryotic cells
    • This observation and fact that mitochondria divide in similar fashion to bacteria, which lead scientists to hypothesize mitochondria evolved from bacterial cells
  113. Chloroplasts
    • found exclusively in plants and algae
    • site of photosynthesis in eukaryotic cells
    • harvest energy of sunlight to generate ATP, which is used to convert CO2 to sugar and starch (an organic form)
  114. endoplasmic reticulum (ER)
    • complex system of flattened sheets, sacs, and tubes
    • Site of synthesis of macromolecules destined for other organelles or the external environment
  115. rough endoplasmic reticulum
    • has characteristic bumpy appearance due to the many ribosomes adhering to surface
    • site where proteins not destined for cytoplasm are synthesized
    • include proteins targeted for secretion or transfer to an organelle's lumen
  116. smooth endoplasmic reticulum
    • functions in lipid synthesis and degradation, and calcium storage
    • vesicles transfer compounds from smooth ER to Golgi apparatus
  117. Golgi apparatus
    • consists of a series of membrane-bound flattened compartments
    • Site where macromolecules synthesized in ER are modified before transported in vesicles to other destinations
  118. Lysosomes
    • digestion of macromolecules
    • organelles that contain a number of powerful degradative enzymes that could destroy the cell if not contained within the organelle
    • endosomes and phagosomes fuse so material taken up by cell can be degraded
  119. Peroxisomes
    • Site where oxidation of lipids and toxic chemicals occur
    • the organelles in which o2 is used to help break down lipids and detox certain chemicals
Card Set
Micro ch3
Micro ch 3