levinson questions Flashcards
1: Each of the following statements concerning the surface structures of bacteria is correct except:
A: Pili mediate the interaction of bacteria with mucosal epithelium
B: Polysaccharide capsules retard phagocytosis
C: Both gram-negative rods and cocci have lipopolysaccharide (“endotoxin”) in their cell wall
D: bacterial flagella are nonantigenic in humans because they closely resemble human flagella in chemical composition
D
2: each of the following statements concerning peptidoglycan is correct except:
A: it has a backbone composed of alternating units of muramic acid and acetylglucosamine
B: cross-links between the tetrapeptides involved D-alanine
C: it is thinner in gram-positive than in gram-negative cells
D: it can be degraded by lysozyme
C
3: each of the following statements concerning bacterial spores is correct except:
A: their survival ability is based on their enhanced metabolic activity
B: they are formed by gram-positive rods
C: they can be killed by being heated to 121 degrees for 15 minutes
D: they are formed primarily when nutrients are limited
A
16: the identification of bacteria by serologic tests is based on the presence of specific antigens. which on of the following bacterial components is least likely to contain useful antigens? A: capsule B: flagella C: exotoxins D: ribosomes
D
20: each of the following statements concerning the gram stain is correct except:
A: escherichia coli stains pink because it has a thin peptidoglycan layer
B: streptococcus pyogenes stains blue because it has a thick peptidoglycan layer
C: mycobacterium tuberculosis stains blue because it has a thick lipid layer
D: mycoplasma pneumoniae is not visible in the gram stain because it does not have a cell wall
C
22: in the gram stain, the decolorization of gram-negative bacteria by alcohol is most closely related to;:
A: proteins encoded by F plasmids
B: lipids in the cell walls
C: 70S ribosomes
D: branched polysaccharides in the capsule
B
26: bacterial surface structures that show antigenic diversity include each of the following except: A: pili B: capsules C: flagella D: peptidoglycan
D
37: each of the following statements concerning the structure and chemical composition of bacteria is correct except:
A: some gram-positive cocci contain teichoic acid external to teh peptidoglycan
B: some gram-positive rods produce spores that are resistant to boiling
C: some gram-negative rods contain lipid A in their outer cell membrane
D: some mycoplasms contain pentaglycine in their peptidoglycan
D
each set of matching question in this section consists of a list of lettered options followed by several numbered items. for each numbered item, select the one lettered option that is most closely associated with it.
A: capsule B: periplasmic space C: peptidoglycan D: lipid A E: 30S ribosomal subunit F: G protein G: Pilus H: ADP-ribosyliating enzyme I: mesosome J: Flagellum K: transposon
536: is the site of action lysozyme
C
each set of matching question in this section consists of a list of lettered options followed by several numbered items. for each numbered item, select the one lettered option that is most closely associated with it.
A: capsule B: periplasmic space C: peptidoglycan D: lipid A E: 30S ribosomal subunit F: G protein G: Pilus H: ADP-ribosyliating enzyme I: mesosome J: Flagellum K: transposon
537: mediates adherence of bacteria to mucous membranes
G
each set of matching question in this section consists of a list of lettered options followed by several numbered items. for each numbered item, select the one lettered option that is most closely associated with it.
A: capsule B: periplasmic space C: peptidoglycan D: lipid A E: 30S ribosomal subunit F: G protein G: Pilus H: ADP-ribosyliating enzyme I: mesosome J: Flagellum K: transposon
538: is the toxic component of endotoxin
D
block two, 4: regarding the gram stain, which one of the following is the most accurate?
A: after adding the crystal violet and gram’s iodine, both gram-positive bacteria and gram-negative bacteria will appear blue
B: if you forget to stain with the red dye (safranin or basic fuchin), both gram-positive bacteria and gram-negative bacteria will appear blue
C: if you forget to heat-fix, both gram-positive bacteria and gram-negative bacteria will appear blue
D: one reason why bacteria have a different color in this stain is because the gram-positive bacteria have lipid in their membrane, whereas gram-negative do not
A
block two, 8: regarding bacterial spores, which one of the following is the most accurate?
A: one spore germinates to form one bacterium
B: they are produced primarily within human red blood cells
C: they are killed by boiling by at sea level but not high altitude
D: they are produced by anaerobes only in the presence of oxygen
E: they contain endotoxin, which accounts for their ability to cause disease
A
27: the effects of antibody on bacteria include each of the following except:
A: lysis of gram-negative bacteria in conjunction with complement
B: augmentation of phagocytosis
C: increase in the frequency of lysogeny
D: inhibition of adherence of bacteria to mucosal surfaces
C
19: each of the following is a typical property of obligate anaerobes except:
A: they generate energy by using the cytochrome system
B: the grow best in the absence of air
C: They lack superoxide dismutase
D: the lack catalase
A
