micro test 2

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created 2 years ago by Autumn_Peart
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updated 2 years ago by Autumn_Peart
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microbiology
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1

characteristics of prokaryotic cells

one chromosome

not in a membrane

bacteria; peptidoglycan cell walls

divides binary fission

2

characteristics of eukaryotic cells

paired chromosomes

has histones and organelles

has polysaccharide cell walls

divides by mitosis

3

whats the size, shape, and arrangement of bacterial cells

0.2 to 2.0 microm diameter & 2-8 microm length

most are monomorphic (single shape)

all are pleomorphic (many shapes)

4

what shape is bacillus?

rod shaped

5

what shape is coccus?

spherical

6

what are glycocalyx?

external to the cell wall (an outer covering) of everything

its viscous/gelatinous

prevents phagocytosis

polysaccharide and/or polypetide

sits/grows on ur teeth

there are 2 types:

capsule (organized/attached)

slime layer (unorganized and loose)

7

identify the names for the following arrangements of bacteria:

pairs:

clusters:

chains:

pairs= diplococci or diplobacilli

clusters= staphylococci

chains= streptococci or streptobacilli

8

what are glycocalyx?

external to the cell wall (an outer covering) of everything

its viscous/gelatinous

polysaccharide and/or polypetide

sits/grows on ur teeth

there are 2 types:

capsule (organized/attached)

slime layer (unorganized and loose)

9

what are flagella and what do they do?

its a filamentous appendage external to the cell that enables bacteria to swim (propels them)

they have antigens on them ex: the H antigen of some gram negative bacteria like E. coli

10

flagellae (the different kinds)

atrichous: no flagellum

monotrichous

polar: flagellum at one end

peritrichous: distributed over whole cell

11

what are fimbriae

hairlike appendages that let things attach

12

what are pili

their involved in gliding/twitching motility

13

what are conjugation pili

help with DNA transfer from cells to other cells

14

what are the purposes of the cell wall?

protects the cell membrane, prevents osmotic lysis, contributes to pathogenicity, made of peptidoglycan (in bacteria)

15

peptidoglycan is composed of?

composed of : N- acetylglucosamine, N- acetyl muramic acid, & polypeptides

16

the gram negative bacterial cell wall is composed of?

an outer lipid membrane (made of polysaccharides, lipoproteins, phospholipids), peptidoglycan, & a periplasmic space (between the outer membrane and plasma membrane)

(has 4 rings in body of flagella)

(*** the peptidoglycan is found in the periplasmic space***)

17

Streptomycin:

acts on bacterial ribosomes and is different than other prokaryotic ribosomes, also has some toxicity for mammals particularly renal

18

teichoic acids:

are important components of gram positive cell walls, are specific bacterial antigens, and contain glycerol or ribitol

  • also regulate movement of cations
  • also link to peptidoglycan
  • also link cell wall to plasma membrane
19

what does the gram negative cell wall protect from?

phagocytes, complement, and antibiotics

20

Gram negative cell walls are made of lipopolysaccharide. what does O polysaccharide do? what is lipid A?

  • functions as an antigen
  • an endotoxin in the top layer
21

what do porins do?

their proteins that form channels through the membrane

22
  1. what is penicillin?
  2. how does it work?
  3. which bacterial constituent does it act on?
  1. a Beta lactam antibiotic
  2. by preventing formation of cross bridges in peptidoglycan, its cytotoxic in growing bacteria
  3. peptidoglycan
23
  1. gram positive has _______ susceptibility to penicillin.
  2. gram negative has _______ susceptibility to penicillin.
  3. which bacteria is more susceptible to lysozyme?
  1. (+) high
  2. (-) low
  3. gram positive.
24

explain the difference between the gram staining process in gram negative vs. gram positive bacteria

in gram positive the peptidoglycan is thicker so the bacteria remains stained purple through the decolorization process. (alcohol dehydrates the peptidoglycan)

in gram negative the peptidoglycan walls are thinner so the alcohol decolorizes the crystal violet therefore safranin is needed to stain the bacteria a pink color (alcohol dissolves the outer membrane and leaves holes in peptidoglycan)

25

what toxins do gram negative produce?

gram positive?

(-) endo and exotoxins (which is why susceptibility to penicillin is low)

(+) exotoxins

26

the primary antibody response is

IgM

27

The secondary response is usually

IgG and its of greater magnitude and more specific

28

what kind of cells are CD4+?

T Helper cells (TH)

  • TCR recognizes and binds to the antigen and MHC class 2 on APC
  • Then APC or TH secrete a molecule to activate the TH cell
29

what kind of cells are CD8+?

T Cytotoxic cells

  • They are activated into Cytotoxic T lymphocytes by TH
30

What are CTL's and what do they do?

cytotoxic T lymphocyte;

they kill self cells that have infection

31

what do self cells do?

they carry endogenous antigens on a surface with MHC molecules

32

CTL releases perforin and granzymes in the infected cell, what does this induce?

apoptosis

33

what do T Regulatory (T reg) Cells do?

Regulate immune response and help maintain self-tolerance

34

what Antibody-Dependent Cell-Mediated Cytotoxicity microorganisms are too large to be phagocytized?

protozoa's and helminths

35

Clonal Selection differentiates activated B cells into:

antibody producing plasma cells or memory cells

36
  1. bacitracin
  2. vancomycin
  1. works against gram positives
  2. last line against MRSA
37

Cephalosporins

are a B-lactem antibiotic that work similar to penicillin

38
  1. Eukaryotes are?
  2. prokaryotes are?
  1. 80S
  2. 70S
39

Amphotericin B acts on the ergosterol component of the plasma membrane of?

fungi

40

ribosomes:

the sites of protein synthesis; 70S

41

Streptomycin:

is aminoglycoside and its inactivates the 30S portion of prokaryotic 70S ribosome, also has some toxicity for mammals particularly renal

42

what are endospores produced by?

bacillus and clostridium; their produced when nutrients are depleted and they are resting cells

43

endospores are resistant to

desiccation, heat, chemicals, and radiation

44

sporulation

the formation of endospores

45

germination

endospore returns to vegetative state

46

the cell wall is found in?

made of?

-plants, algae, and fungi

-made of carbs (cellulose, plants, chitin, fungi, glucan, yeasts)

47

glycocalyx is made of

carbs bonded to proteins and lipids in the plasma membrane; found in animal cells

48

the cytoplasmic membrane is similar to

the structure of prokaryotic cell membranes; it has a phospholipid bilayer & integral and peripheral proteins

49

the plasma cytoplasmic membrane is different in structure of prokaryotic cell membranes how?

it has sterols (complex lipids)

and carbs for attachment/ cell to cell recognition

50

fungi

are eukaryotes with chitin cell walls

yeasts are unicellular fungi

molds/mushrooms are multicellular

fungi are like a connected chain and yeasts are circular in clusters

51

amphotericin B

only targets fungal infections, it likes sterols (ergosterol, cholesterol), binds sterols of mammal membranes to some extent causing toxicity

52

mitochondria:

double membraned, contain inner folds (cristae), and fluid (matrix), and are involved in cellular respiration (ATP production)

53

systemic anaphylaxis

when a person is sensitized to an antigen and then exposed to it again, may result in death, is treated with epinephrine

54

localized anaphylaxis

associated with ingested or inhaled antigens

55

symptoms of systematic anaphylaxis

trouble breathing, hives, tightness of throat, nausea, vommiting, diarrhea, abdominal pain, low BP, dizzy, fainting, rapid HR

is treated with: epinephrine, oxygen, IV antihistamine, albuterol

56

what is the process that eliminates harmful B cells called?

clonal deletion

57

the strength of the bond of an antigen to an antibody

affinity

58

the antigen-antibody complex contributes to host defense in the following ways:

opsonization, antibody dependent cell mediated toxicity, complement activation, neutralization, & agglutination.

59

secondary response (memory or anamnestic) response will occur when?

after the second exposure to an antigen; its more rapid, lasts many dyas, greater in magnitude

60

after the initial exposure to an antigen memory cells are produced; how are they activated?

the secondary exposure activates them

61

what is apoptosis?

cell death; prevents the spread of viruses into other cells

62

whats the function of natural killer (NK) cells?

  • attacks/destroys target cells
  • helps with antibody dependent cell-mediated toxicity.
63

antigen Rh is found on what percent of the population

85% of the populations RBC's

64

what does ethambutol do?

inhibits incorporation of mycolic acid into the cell wall

65

what does isoniazid do?

inhibits the mycolic acid synthesis in mycobacteria

66

protoplast (susceptible to osmotic lysis)

a wall-less gram positive cell

67

spheroplast (susceptible to osmotic lysis)

is wall less gram negative cell