M3: Biology of Pathogens/Bacteria I Flashcards Preview

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Flashcards in M3: Biology of Pathogens/Bacteria I Deck (44)
1

Major divisions of pathogens (3)

viruses

prokaryotes (no nucleus): Bacteria and Archaea (no proven role in human disease-maybe periodontal disease?)

eukaryotes (with a nucleus)

2

Viruses:

cells (eukaryotic / prokaryotic / no)

size (smallest / small / large / largest)

nucleic acid: DNA (and / or) RNA

ribosomes (80S / 70S / no)

mitochondria (yes / no)

cell wall (peptidoglycan / chitin / none)

motility (usually / sometimes / none)

reproduction by binary fission (yes / no)

no

smallest

or

no

no

none

none

no

3

Bacteria:

cells (eukaryotic / prokaryotic / no)

size (smallest / small / large / largest)

nucleic acid: DNA (and / or) RNA

ribosomes (80S / 70S / no)

mitochondria (yes / no)

cell wall (peptidoglycan / chitin / none)

motility (usually / sometimes / none)

reproduction by binary fission (yes / no)

prokaryotic

small

and

70S

no

peptidoglycan

sometimes

yes

4

Fungi:

cells (eukaryotic / prokaryotic / no)

size (smallest / small / large / largest)

nucleic acid: DNA (and / or) RNA

ribosomes (80S / 70S / no)

mitochondria (yes / no)

cell wall (peptidoglycan / chitin / none)

motility (usually / sometimes / none)

reproduction by binary fission (yes / no)

eukaryotic

large

and

80S

yes

chitin

none

yes

5

Protozoa/Helminths (Parasites):

cells (eukaryotic / prokaryotic / no)

size (smallest / small / large / largest)

nucleic acid: DNA (and / or) RNA

ribosomes (80S / 70S / no)

mitochondria (yes / no)

cell wall (peptidoglycan / chitin / none)

motility (usually / sometimes / none)

reproduction by binary fission (yes / no)

eukaryotic

largest

and

80S

yes

none

usually

yes

6

Viruses:

(obligate/facultative) (intracellular/extracellular) pathogens (they require the host cell for _)

Have DNA (and/or) RNA.

No independent _ production or _ synthesis

Usually show selectivity for infecting _

Not sensitive to _ (e.g. penicillins)

obligate intracellular
replication

or (not both)

energy
protein

particular types and/or species of host cells

antibacterial/antifungal antibiotics

7

Bacteria (prokaryotes):

DNA enclosed by a nuclear membrane (yes / no)

chromosome number (usually 1 / >1)

membrane-bound organelles, e.g., mitochondria (yes / no)

ribosomes (70S / 80S)

peptidoglycan in cell wall (yes, except _ / no)

sterols in plasma membrane (yes / no, except _)

no

usually 1

no

70S

yes, except Mycoplasma spp. & (probably) Chlamydiae spp.

no, except Mycoplasma spp., Helicobacter pylori & Borrelia burgodorferi

8

Eukaryotes:

DNA enclosed by a nuclear membrane (yes / no)

chromosome number (usually 1 / >1)

membrane-bound organelles, e.g., mitochondria (yes / no)

ribosomes (70S / 80S)

peptidoglycan in cell wall (yes, except _ / no)

sterols in plasma membrane (yes / no, except _)

yes

>1

yes

80S

no

yes

9

Bacteria:

Bacteria lack _ and _

Bacteria usually have _ made of _ (exceptions: _ and _)

Bacteria have _ ribosomes

Bacteria (and eukaryotes) have RNA (and/or) DNA, make their own _ (except for
_ and _) and have independent _ synthesis

Most Bacteria lack _ in their plasma membrane (except _, _, and _)

Bacteria are usually about 1/5th to 1/10th the size of _ (need _ to visualize)

nuclei and internal organelles

cell walls
peptidoglycan
Mycoplasma and Chlamydiae

70S

and
energy (Rickettsiae and Chlamydiae)
protein

sterols (Mycoplasma spp., Helicobacter pylori and Borrelia burgodorferi)

eukaryotes
oil immersion lens

10

Bacteria:

morphology (3)

arrangements (3)

cocci
rods
spirochete

diplococci
cocci in chains
cocci in clusters

11

Bacterial Cell Components (3)

Cytoplasm
Cell envelope
External structures (if present)

12

Bacterial Cell Components:
Cytoplasm (3)

DNA, ribosomes, metabolic enzymes

site of some antibiotic action

outer membrane (if present)

13

Bacterial Cell Components:
Cell envelope (3)

plasma membrane

cell wall (target of some antibiotic action)

outer membrane (if present)

14

Bacterial Cell Components:
External structures (if present) (4)

common pili

capsule

sex pilus

flagella

15

Role of Bacterial Cell Components:
Cytoplasm:

DNA, ribosomes, metabolic enzymes: _ processes

site of some antibiotic action (e.g., _ inhibitors, antibiotics affecting _ or _)

plasmids: antibiotic _ and _

basic life

protein synthesis
DNA replication or RNA transcription

resistance and virulence

16

Role of Bacterial Cell Components:
Cell envelope:

plasma membrane: _ and _

cell wall (target of some antibiotic action): resists _

outer membrane (if present): _ (but contains _ and _)

permeability barrier and transport

osmotic lysis

permeability barrier
pumps and pores

17

Role of Bacterial Cell Components:
External structures (if present):

common pili: _

capsule: _, can result in _ formation

sex pilus: _

flagella: _

attachment to tissue

antiphagocytic
biofilm

conjugation

motility

18

Bacterial Cell Wall Synthesis:

_ crosslinking is carried out by _ (also known as _).

Peptidoglycan
transpeptidases
penicillin binding proteins (PBPs)

19

The Gram Stain:
Procedures (4)

stain
mordant
decolorize
counterstain

20

The Gram Stain:
Gram+ and Gram- procedure colors

Stain

Mordant

Decolorize

Counterstain

Stain: purple, purple

Mordant: purple, purple

Decolorize: purple, clear

Counterstain: purple, red

21

Structures/components unique to gram+ bacteria (2)

Lipoteichoic acid
Teichoic acid

22

Examples of medically-important gram+ bacteria (3)

Streptococcus spp.
Staphylococcus spp.
Clostridium spp.

23

Structures/components unique to the gram-bacteria include the _

Some gram-s (e.g. the _) contain _

outer membrane

enterics
lipopolysaccharide (LPS)

24

Structures/components unique to the Gram-negative bacteria:

LPS consists of three regions (3)

lipid A
core
O antigen

25

Structures/components unique to the Gram-negative bacteria:

LPS consists of three regions:

lipid A: has _ activity

a core: _

O antigen: important for _ and _, very variable _

endotoxic

conserved

bile and complement resistance
polysaccharide

26

Gram-negatives can be stereotyped for their antigens (3)

O
H
K

27

Gram-negative antigens:

O: _, _ portion of LPS

H: found on _

K: _ antigen

variable, outermost

flagella

capsular

28

Some (mostly _) Gram-negative bacteria have an LPS-like molecule in their outer membrane instead of true LPS.

This molecule, _, lacks the _ antigen but retains the _ and _ regions of LPS.

nonenteric

lipooligosaccharide (LOS)

O
core
lipid A

29

Being gram- vs. gram+

Advantage: _ from the _ (including some antibiotics)

Disadvantage: _ to make, hard to _ through _

Protection from the environment

expensive
secrete proteins through two membranes

30

Structures/components unique to the Gram-negative bacteria:

_: channels in outer membrane, allow molecules to _

Alterations can impact _

Porins
move across the outer membrane

antibiotic resistance

31

Some examples of Gram negative pathogens (4)

Shigella spp.
Salmonella spp.
Vibrio cholerae
E. coli

32

"Atypical" Myobacteria:

Stain: _

Cell envelope functions (2)

Cell envelope components (4)

Acid-fast

resistance to desiccation & phagocytosis
helps disease transmission

waxy layer
phenolic glycolipid
mycolic acids
peptidoglycan

33

Examples of medically-important Mycobacterium spp. (2)

Mycobacterium tuberculosis

Mycobacterium leprae

34

"Atypical" Spirochetes:

These bacteria can be visualized only by _

Examples (2)

dark-field microscopy

Borrelia burgdorferi
Treponema pallidum

35

"Atypical" Rickettsiae spp.:

Distinguishing features: (facultative/obligate) (intracellular/extracellular) bacteria that are _

Rickettsiae spp. generate some _ but probably need to get some from host cell

Can be transmitted by _

Have typical Gram(+/-) envelope, but too small to _

obligate intracellular
vector-borne

energy

fleas, ticks, lice, etc.

negative
Gram-stain

36

Medically important Rickettsiae spp. (2)

R. rickettsii: rocky mountain spotted fever

R. typhi: endemic typhi

37

"Atypical" Chlamydiae and Chlamydophila spp.:

These are (facultative/obligate) (intracellular/extracellular) bacteria with a complex life cycle (_ bodies and _ bodies)

_ parasites

Have (#) membranes like Gram-negatives, but no _

Too small to see by _ stains

obligate intracellular
reticulate
elementary

Energy

two
peptidoglycan

Gram

38

Examples of medically important spp. (3)

Chlamydiae trachomatis: blindness, nongonococcal urethritis, pneumoniae

Chlamydophila psittaci: psittacosis (a form of pneumonia)

Chlamydophila pneumoniae: pneumonia

39

Chylamydiae:

Can grow outside host cell (yes / yes, except / no / no, except)

Have independent protein synthesis (yes / no)

Generate metabolic energy (yes / no / sometimes)

Shown to have peptidoglycan-containing cell wall (yes / no / no except)

Susceptible to antibiotics (yes / no)

Reproduced by binary fission (yes / no)

Nucleic acids (DNA and / or RNA)

no

yes

no

no, except Chlamydiae have two membranes (like gram-negative bacteria) but have not been shown to have a peptidoglycan

yes

yes

and

40

Typical bacteria:

Can grow outside host cell (yes / yes, except / no / no, except)

Have independent protein synthesis (yes / no)

Generate metabolic energy (yes / no / sometimes)

Shown to have peptidoglycan-containing cell wall (yes / no / no except)

Susceptible to antibiotics (yes / no)

Reproduced by binary fission (yes / no)

Nucleic acids (DNA and / or RNA)

yes, except for a few obligate intracellular pathogens, e.g., Mycobacterium leprae

yes

yes

yes

yes

yes

and

41

Rickettsiae:

Can grow outside host cell (yes / yes, except / no / no, except)

Have independent protein synthesis (yes / no)

Generate metabolic energy (yes / no / sometimes)

Shown to have peptidoglycan-containing cell wall (yes / no / no except)

Susceptible to antibiotics (yes / no)

Reproduced by binary fission (yes / no)

Nucleic acids (DNA and / or RNA)

no, except for Rochalimaea quintana

yes

sometimes

yes

yes

yes

and

42

Mycoplasma:

Can grow outside host cell (yes / yes, except / no / no, except)

Have independent protein synthesis (yes / no)

Generate metabolic energy (yes / no / sometimes)

Shown to have peptidoglycan-containing cell wall (yes / no / no except)

Susceptible to antibiotics (yes / no)

Reproduced by binary fission (yes / no)

Nucleic acids (DNA and / or RNA)

yes

yes

yes

no

yes

yes

and

43

Virus:

Can grow outside host cell (yes / yes, except / no / no, except)

Have independent protein synthesis (yes / no)

Generate metabolic energy (yes / no / sometimes)

Shown to have peptidoglycan-containing cell wall (yes / no / no except)

Susceptible to antibiotics (yes / no)

Reproduced by binary fission (yes / no)

Nucleic acids (DNA and / or RNA)

no

no

no

no

no

no

or

44

"Atypical" Mycoplasma spp.:

Very (large/small), lack a _, and have _ in their
plasma membranes

Can be (slowly) grown on _ media

The absence of a cell wall affects _ sensitivity

The major pathogenic Mycoplasma spp. is _ (causes an atypical _)

small
cell wall
sterols

artificial

antibiotic

M. pneumoniae
pneumonia