Exam 1 Medical Microbiology Questions and
Answers
1. DNA base sequence analysis correct answers: current Gold standard, do not need to
sequence whole genome, just the conserved part
2. Components of Gram's Stain correct answers:
Crystal violet (blue stain) Iodine (fix blue dye to cell wall
peptidoglycan)
Acetone-alcohol (decolorizes)
Sattranin (red counter
stain)
3. Acid Fast Stain correct answers: Stained red by carbolfuchsin and auramine O (fluorescent).
Dyes removed by acid/acid-alcohol and counterstained with blue-green dye to
visualize. Those retain primary dye are Acid-Fast, nonAcid-Fast stain
blue/background color
4. Mycobacteria and Nocardia correct answers: Acid-Fast Bacteria
5. halophilic correct answers: high NaCl requirements
6. psychrophilic correct answers: 0-20 deg C. Few organisms involve human pathogens
7. mesophilic correct answers: 20-45 deg C. Most human pathogens
8. thermophilic correct answers: 46-80 deg C. Very rare to be human pathogens
9. capnophilic correct answers: Love CO2, do not do well in regular atmosphere
10. aerobic correct answers: high redox +150 mv
11. microaerophilic correct answers: doesn't require high redox, but oxygen still required.
Well adapted to human hosts. Many pathogens.
12. Faculative correct answers: high or low redox requirement
13. Anaerobic correct answers: Aerotolerant, Moderate obligate, Strict
obligate (very fragile to grow). Most pathogenic anaerobes are in the middle
range.
14. Respiration correct answers: final electron acceptor is an inorganic compound
15. Fermentation correct answers: final electron acceptor is an organic compound
16. Current genotype classification by correct answers: Nucleic acid analysis by
amplification and sequencing of specific conserved target regions, like the one on 16S
,ribosomal RNA gene
17. Amplify variable correct answers: compare patients
18. Amplify conserved correct answers: isolate species
19. Nuclear
envelope correct
answers: capsule outer cell
membrane (gram neg only) cell
wall
inner (cytoplasmic) membrane - analogous to eukaryotic membrane
, 20. capsule correct answers: produced by some not all bacteria
production dependent on nutritional and environmental
conditions mostly carbohydrate composition/constructed
polymers
large capsules prevent organisms from being
phagocytksed Antigenic, K antigens
21. protoplasts correct answers: results from loss of murein (peptidoglycan) layer
22. Murein (peptidoglycan) correct answers: may be associated with proteins &
carbohydrates/teichoic acids which have antiphagocytic role and activate complement cascade
and elicit cytokine production
23. Lipoteichoic acids correct answers: fatty acids anchored in cytplasmic membrane.
surface antigens, promote host attach- ment and stimulate cytokines through leukocytes
24. Peptidoglycan layer correct answers:
in both gram post & gram neg major component
of gram pos
provides shape and rigidity to cell wall
assembled by enzymes in cytoplasmic
membrane
composed of interconnected alternating NAG and NAM units
25. Crosslinking correct answers: 5 amino acids, from L-Lys to D-Ala
26. Carboxypeptidase correct answers: removes terminal alanine to allow cross linking
27. Transpeptidase correct answers: transfers amino acids in proper order and is
responsible for cross linking
28. Penicilin correct answers: inhibition of transpeptidase preventing crosslinking
construction
29. Vancomycin correct answers: binds to terminal Alanine preventing carboxypeptidase
action
30. Porins correct answers: outer membrane proteins that control passage of nutrients and other
substances into the cell. conforma- tion of porins can change and block entrance of drugs. porins very
important in modulating susceptibility & resistance
31. Lipopolysaccharide correct answers: outer membrane component that is the endotoxin
(gram neg bacteria)
32. Periplasmic space correct answers: compartment holding many hydrolytic enzymes,
Answers
1. DNA base sequence analysis correct answers: current Gold standard, do not need to
sequence whole genome, just the conserved part
2. Components of Gram's Stain correct answers:
Crystal violet (blue stain) Iodine (fix blue dye to cell wall
peptidoglycan)
Acetone-alcohol (decolorizes)
Sattranin (red counter
stain)
3. Acid Fast Stain correct answers: Stained red by carbolfuchsin and auramine O (fluorescent).
Dyes removed by acid/acid-alcohol and counterstained with blue-green dye to
visualize. Those retain primary dye are Acid-Fast, nonAcid-Fast stain
blue/background color
4. Mycobacteria and Nocardia correct answers: Acid-Fast Bacteria
5. halophilic correct answers: high NaCl requirements
6. psychrophilic correct answers: 0-20 deg C. Few organisms involve human pathogens
7. mesophilic correct answers: 20-45 deg C. Most human pathogens
8. thermophilic correct answers: 46-80 deg C. Very rare to be human pathogens
9. capnophilic correct answers: Love CO2, do not do well in regular atmosphere
10. aerobic correct answers: high redox +150 mv
11. microaerophilic correct answers: doesn't require high redox, but oxygen still required.
Well adapted to human hosts. Many pathogens.
12. Faculative correct answers: high or low redox requirement
13. Anaerobic correct answers: Aerotolerant, Moderate obligate, Strict
obligate (very fragile to grow). Most pathogenic anaerobes are in the middle
range.
14. Respiration correct answers: final electron acceptor is an inorganic compound
15. Fermentation correct answers: final electron acceptor is an organic compound
16. Current genotype classification by correct answers: Nucleic acid analysis by
amplification and sequencing of specific conserved target regions, like the one on 16S
,ribosomal RNA gene
17. Amplify variable correct answers: compare patients
18. Amplify conserved correct answers: isolate species
19. Nuclear
envelope correct
answers: capsule outer cell
membrane (gram neg only) cell
wall
inner (cytoplasmic) membrane - analogous to eukaryotic membrane
, 20. capsule correct answers: produced by some not all bacteria
production dependent on nutritional and environmental
conditions mostly carbohydrate composition/constructed
polymers
large capsules prevent organisms from being
phagocytksed Antigenic, K antigens
21. protoplasts correct answers: results from loss of murein (peptidoglycan) layer
22. Murein (peptidoglycan) correct answers: may be associated with proteins &
carbohydrates/teichoic acids which have antiphagocytic role and activate complement cascade
and elicit cytokine production
23. Lipoteichoic acids correct answers: fatty acids anchored in cytplasmic membrane.
surface antigens, promote host attach- ment and stimulate cytokines through leukocytes
24. Peptidoglycan layer correct answers:
in both gram post & gram neg major component
of gram pos
provides shape and rigidity to cell wall
assembled by enzymes in cytoplasmic
membrane
composed of interconnected alternating NAG and NAM units
25. Crosslinking correct answers: 5 amino acids, from L-Lys to D-Ala
26. Carboxypeptidase correct answers: removes terminal alanine to allow cross linking
27. Transpeptidase correct answers: transfers amino acids in proper order and is
responsible for cross linking
28. Penicilin correct answers: inhibition of transpeptidase preventing crosslinking
construction
29. Vancomycin correct answers: binds to terminal Alanine preventing carboxypeptidase
action
30. Porins correct answers: outer membrane proteins that control passage of nutrients and other
substances into the cell. conforma- tion of porins can change and block entrance of drugs. porins very
important in modulating susceptibility & resistance
31. Lipopolysaccharide correct answers: outer membrane component that is the endotoxin
(gram neg bacteria)
32. Periplasmic space correct answers: compartment holding many hydrolytic enzymes,
