Micro quiz ch 9

  1. What is a glycocalyx?
    • The glycocalyx is a sticky substance composed of polypeptides (diff between the ones in our cells and bacterial cells), polysaccharides (same in our cells and bacterial cells) or both.
    • It is produced in the cytoplasm and secreted to the outer part of the cell wall.
    • It provides a protective element against environmental stress.
  2. It can be used for nutrition.
  3. Bacteria can draw back in sugar for use of energy
  4. What makes the glycocalyx a slime layer/capsule?
    If loosely attached to the wall, it is called a slime layer.

    • If adhered tightly to the wall, it is called a capsule.
    • Both variations give an adherence capability to the organism.
    • Capsules and slime layers are more typical of graham positive
  5. Clinical significance of glycocalyx?
    • The slime layer form is associated with some forms of dental decay.
    • The capsule form:

    • - Inhibits phagocytosis
    • - Many organisms are not infectious without a capsule

    - Capsule genes can be transferred between organisms.
  6. How are fimbriae and pili alike?
    Both are involved in adherence.

    • Both appear as sticky projections which are shorter than flagella.
    • They are found on Gram-negative organisms.
    • Both are composed of pilin protein subunits.
  7. Conjugation Pili
    • Used for transfer to another cell, sometimes “sex” pilus, allows for sex between 2 bacteria. Bacteria can pick up plama, short pieces of DNA
    • Bacteria can produce pili,
    • find another bacteria to attach to it,
    • replicate DNA, transfer plasma DNA over to the next step, now new cell has the
    • DNA and that is the purpose of pili, to move DNA from one bacteria to the
    • next.
  8. Axial Filaments
    • Axial filaments are little modified flagella or endoflagella that wrap around
    • spirochete and allow for movement
    • The corkscrew motion gives the bacterium the ability to bore through tissue (staying in).
    • They allow organisms to get into the blood as well as other tissues (damage the host).
  9. What are flagella?
    • Flagella are used only for motility.
    • They are long structures that extend far beyond the cell wall and even beyond the glycocalyx.
    • They make it possible for bacteria to move from their point of origin to other places in the body.
    • Example: E. coli can move from the large intestine, where it is harmless, to the urinary tract, where it can cause serious infection.
    • Not used for attachment
  10. Flagella and their roters
    • Basically allows bacteria to swim, gives it a propeller
    • Flagella have a roter that is the moving force for the flagella
    • Being gram + or gram – will depend on outer region or basil body of the portion of the flagella.
    • The roter allows the flagella to rotate and 360 degrees.
  11. Monotrichous
    • Monotrichous – one flagellum located at the end of the cell
    • Amphitrichous – two flagella, one at each end of the cell
    • Lophotrichous – two or more flagella located at the same end of the cell
    • Peritrichous – flagella surround the entire cell.
  12. Flagella movement allows for
    • opportunistic infections
    • escape from host defense (defeat of host defense)
    • systemic infection ( can create just through movement)
  13. Flagella movement directions
    • Clockwise – bacteria tumbles and changes direction
    • Counterclockwise- bacteria runs in a single direction
  14. length and number flagella
    • - Sometimes pili will be longest and sometimes flagella will, on ave prob the same length
    • -Can be monotrichous and can also have a very high amount
  15. Length and number fimbriae
    • - Shortest
    • - Has the most, are everywhere, are there to coat the bacterial
  16. length and number pili
    • - sometimes pili will be longest and sometimes flagella, on ave prob the same length
    • -will have least amount
Card Set
Micro quiz ch 9
micro quiz ch 9