X_Exam1 Mfm2_6

Front 1

what are the steps to the gram stain:

Back 1

1. stain with crystal violet
2. add iodine soln
3. decolorize with alcohol
4. counterstain with safranin

Front 2

what does alcohol do to the crystal violet in gram negative cells:

Back 2

extracts it

Front 3

the thick peptidoglycan layer of (Gram-positive/Gram-negative) cells becomes dehydrated by the alcohol. The pores in the peptidoglycan close up and the ... complex remains inside the cell

Back 3

Gram-positive
crystal violet-iodine

Front 4

why is safranin used in gram staining:

Back 4

to visualize gram-negative cells

Front 5

1. what is the type of cell wall do mycobacteria have:
2. and what happens with gram staining:

Back 5

1. typical Gram-positive cell wall structure
2. mycolic acid bound to the outside of the peptidoglycan interferes with the staining procedure

Front 6

what kind of bacteria stain with acid fast:

Back 6

Mycobacterium

Front 7

what 2 organisms discussed in class are too small to be seen with a brightfield microscope and therefore cannot be gram stained:

Back 7

Mycoplasma
Treponema

Front 8

..., ... and ... are gram-negative, however, since they are obligate intracellular parasites, the Gram stain is not useful here

- what would you use to stain these organisms:

Back 8

Chlamydia
Chlamydiophila
Rickettsia
Other sensitive stains, such as fluorescent antibodies

Front 9

what are the gram positive bacilli:
1.
2.
3.
4.
5.

Back 9

1. Bacillus
2. Clostridium
3. Corynebacterium
4. Listeria
5. Propionibacterium

Front 10

what are the gram positive cocci:
1.
2.
3.

Back 10

1. Enterococcus
2. Staphylococcus
3. Streptococcus

Front 11

what are the gram positive filamentous organisms:

1.

Back 11

1. Actinomyces

Front 12

what are the gram negative cocci:

1.
2.

Back 12

1. Moraxella
2.Neisseria

Front 13

what are the gram negative curved or spiral organisms:

1.
2.

Back 13

1. Campylobacter
2. Helicobacter

Front 14

what are the gram negative spirochete:
1.
2.

Back 14

1. Borrelia
2. Leptospira

Front 15

what are the non-gram staining bacilli:
1.
2.

Back 15

1. Mycobacterium
2. Rickettsia

Front 16

what are the non-gram staining cocci:
1.
2.

Back 16

1. Chlamydia
2. Chlamydiophila

Front 17

what are the non-gram staining filamentous organisms:
1.

Back 17

1. Mycoplasma

Front 18

what are the non-gram staining spirochetes:
1.

Back 18

1. Treponema

Front 19

what are the steps to acid fast staining:

Back 19

1. stain with carbol fushin
2. decolorize with acid-alcohol
3. counterstain with methylene blue

Front 20

Acid-fast organisms are stained ... all others are stained ...

Back 20

pink to red
blue

Front 21

what makes acid fast organisms resistant to acid-alcohol decolorizing:

Back 21

mycolic acids

Front 22

identify the labeled structures:

what does this figure depict:

Back 22

(see figure)

Structure of a Gram-negative Bacterium

Front 23

the cytoplasmic membrane is also called the:
1.
2.

Back 23

inner membrane
plasma membrane

Front 24

Phospholipids of inner membranes have a hydrophilic group that faces the ... or ...

Back 24

cytoplasm
periplasm

Front 25

The fatty acids in the plasma membranes of gram positive and gram negative bacteria are typically ... to ... carbons long and have ...(number) or ...(number) double bonds

Back 25

16
18
zero
one

Front 26

In additions to phospholipids, the cytoplasmic membrane of gram positive and gram negative bacteria contains molecules called ... which are similar to the sterols found in eukaryotes and serve to make the membrane more ... and about 1/2 of the membrane mass comes from ...

Back 26

hopanoids
rigid
protein

Front 27

what are the functions of the cytoplasmic membrane of gram positive and gram negative bacteria:
1.
2.
3.

Back 27

1. barrier separating the cytoplasm from the periplasm
2. transport
3. respiration

Front 28

... compounds can diffuse across the membrane to some degree which can be dangerous to the cell, so one function of the ... of the cell envelope is to protect the cytoplasmic membrane from these compounds

Back 28

hydrophobic
outer layers

Front 29

how many layers does the gram-negative cell wall have:
gram-positive:

Back 29

2
1

Front 30

identify the layers of the gram-negative cell wall:

Back 30

peptidoglycan
outer layer

Front 31

what is the shape and composition of the peptidoglycan layer of the gram-negative cell wall:
1.
2.

Back 31

1. peptidoglycan layer is a single sheet
2. composed of two sugars, N-acetylglucosamine and N-acetylmuramic

Front 32

The peptidoglycan chains in the gram-negative cell wall are held together by crosslinks between the ... acids and are composed of ...

Back 32

N-acetylmuramic
short chains of amino acids

Front 33

Gram-negative bacteria, and some Gram-positive bacteria, have the unusual amino acid ... in the peptide crosslink of the peptidoglycan

Back 33

meso-diaminopimelate

Front 34

what is the function of the peptidoglycan layer:

Back 34

provide rigidity to the cell and to prevent it from exploding due to the higher pressure inside the cell than outside it

Front 35

The outer membrane of Gram-negative bacteria is a ... composed of an outer ... layer and an inner ... layer

Back 35

lipid bilayer
lipopolysaccharide (LPS)
phospholipid

Front 36

the LPS has 2 portions, what are they:

Back 36

phospholipid (lipid A)
chains of polysaccharides

Front 37

what portion of the LPS is toxic to humans and what is the toxin called:

Back 37

lipid A
endotoxin

Front 38

what is the function of the sugar side chains of the LPS:

Back 38

prevent diffusion of hydrophobic compounds into the cell

Front 39

The core polysaccharide of the LPS contains 9 to 12 sugar residues and includes the unusual sugar ... while the ... is a 4 to 7 residue polysaccharide that is repeated 50 to 100 times and is called the ... antigen

Back 39

KDO (keto-deoxy-octanoate)
O-specific polysaccharide
O

Front 40

what are porins:

Back 40

proteins that form pores and allow small hydrophillic compounds to enter the cell

Front 41

where are porins located:

Back 41

outer membrane of gram negative bacteria

Front 42

can you use vancomycin against gram negative bacteria?

Back 42

no, too large to get through porin

Front 43

what is the relationship between antibiotic resistance and porins:

Back 43

a lot of antibiotic resistance due to smaller pores in porin

Front 44

space between the outer membrane and the cytoplasmic membrane in Gram-negative bacteria is called the ... space

Back 44

periplasmic

Front 45

what do hydrolytic enzymes do and where are they found in gram negative bacteria:
in gram positive bacteria:

Back 45

break down large complex nutrients
found in the periplasmic space
within mesh of peptidoglycan and the surrounding medium

Front 46

... is found in the periplasm and breakdowns ... antibiotics such as ... and is also secreted into the ...

Back 46

β-lactamase
β-lactam
penicillin
surrounding medium

Front 47

do gram positive or gram negative have a periplasmic space or both:

Back 47

gram negative

Front 48

how does the peptidoglycan layer of gram positive bacteria differ to that of gram negative bacteria:

Back 48

thicker - can be as many as 25 sheets
in the peptide crosslinks the meso-diaminopimelate is often replaced with L-lysine
in some Gram-positive bacteria, a string of glycines connect the amino acid strands in the crosslinks

Front 49

The cell walls of many Gram-positive bacteria contain highly negatively charged polysaccharides called ... that stick out from the peptidoglycan into the medium and help prevent diffusion of ... compounds into the cell

Back 49

teichoic acids
hydrophobic

Front 50

If the teichoic acids are bound to the cytoplasmic membrane, they are known as ...

Back 50

lipoteichoic acids

Front 51

Teichoic acids are common surface antigens that distinguish ... These are important ... factors Lipoteichoic acids are also shed into the environment and cause a weak ... reaction

Back 51

serotypes
virulence
endotoxin-like

Front 52

where are Teichoic acids and lipoteichoic acids NOT found:

Back 52

gram negative bacteria

Front 53

Gram-positive cells lack an ... membrane, so the only barrier to many compounds is the ... membrane, also the peptidoglycan is often the ... layer of the cell

Back 53

outer
cytoplasmic
outermost

Front 54

the bond between N-acetylmuramic acid and N-acetylglucosamine can be broken by ... causing the formation of a protoplast.

the above is true for gram-positive or gram negative bacteria:

Back 54

lysozyme
gram-positive

Front 55

... is found in tears and saliva and is active only against Gram-positive cells

Back 55

Lysozyme

Front 56

lysozyme is effective against gram-negative or gram positive bacteria:

Back 56

gram-positive

Front 57

why isn't lysozyme effective against gram-negative bacteria:

Back 57

lysozyme can’t get through the Gram-negative outer membrane to get at the peptidoglycan