GMS 6121 Exam 3 Quizzes with 100% Correctly Solved

GMS 6121 Exam 3 Quizzes with 100% Correctly Solved Which of the following are NOT accurately described structural relationships of bacteria? a) gram positive: thick peptidoglycan and teichoic acid b) gram negative: outer membrane and LPS c) acid-fast: waxes and lipids d) wall-less: LOS and cholesterol Answer-d) wall-less do have cholesterol from the host but do not have LOS/LPS Why are gram negative bacteria resistant to bacitracin and vancomycin? a) porins b) they lack the targets for these antibiotics c) lipopolysaccharide d) cholesterol e) they have diaminopimelic acid in their peptidoglycan Answer-a) Bacitracin and vancomycin are too big to fit through the porins of the outer membrane Which part of lipopolysaccharide has the biologic/toxic activity? a) the part that binds to TLR2 b) Lipid A c) core oligosaccharide d) O antigen e) every part must be present to have biologic activity Answer-b) lipid A Which type of bacteria make spores? a) wall-less b) acid-fast c) gram (+) rods d) gram (-) rods e) gram (-) and gram (+) rods Answer-c) gram (+) rods Which function is NOT carried out at the bacterial cell membrane? a) transport b) motility c) energy production d) chromosomal segregation e) endocytosis Answer-e) bacteria do not perform endocytosis anywhere A bacterial culture increased from 1,000 to 1,000,000 CFU in 90 minutes. Roughly, what is the doubling time in minutes/generation? (You shouldn't even need a calculator for this.) a) 100 minutes/generation b) 50 minutes/generation c) 10 minutes/generation d) 1 minute/generation e) more information is needed Answer-c) 10 minutes/generation Which antibiotic inhibits bacterial transcription? a) trimethoprim b) neomycin c) rifampin d) methicillin e) azithromycin Answer-c) rifampin rifampin inhibits RNA synthesis subunit beta, which is encoded by rpoB gene. Resistance to rifampin comes from a point mutation in rpoB (KNOW THAT) Which of the following antibiotics does NOT directly affect protein synthesis? a) streptomycin b) tetracycline c) chloramphenicol d) erythromycin e) nalidixic acid Answer-e) nalidixic acid Inhibits DNA synthesis via DNA gyrase What is unusual about type 3 secretion in gram-negative bacteria? a) it uses the Tat secretion system to get proteins across the inner membrane b) all of the secretions functions are contained within a single protein c) it injects proteins into host cells d) after the proteins get into the periplasm, then cross the outer membrane through a beta barrel complex of proteins Answer-c) type III, like type 4 and 6, inject proteins into host cells Which of the following does not accurately describe bacterial biofilms? a) the bacteria often produce a glycocalyx b) bacterial replication is faster than for planktonic cells c) quorum sensing is used to regulate gene expression d) the bacteria are resistant to antibiotics e) biofilms contaminate medical devices in the body Answer-b) because bacteria are so crowded in biofilms, their access to nutrients is very limited, so they grow more slowly Which of the following genetics elements are NOT present in ALL bacteria (i.e., they are optional genetic components)? Click ALL that apply (this is not single best answer). a) chromosome b) plasmids c) bacteriophage d) insertion sequences e) transposons b, c, d, and e: these are all optional What is the most critical aspect of a bacteriophage to enable it to participate in generalized transduction? a) being a lytic phage b) being a temperate phage