A bacterial culture contains 10^8
CFU/mL. 100 uL are spread
onto a plate containing the antibiotic erythromycin. 20
erythromycin^r colonies appear the next day. What is the
frequency of erythromycin^r mutations?
A. 2 x 10-8
B. 2 x 10-7
C. 2 x 10-6
D. 2 x 10-5 Correct Answers C. 2 x 10-6
mutation frequency = (mutants/mL) ÷ (CFU/mL) = (20
Erythromycin^r / 0.1 mL) ÷ (10^8 CFU / 1mL) = 2x10^2 ÷ 10^8
= 2x10^-6
A coliform bacteria is all of the following except:
A. gram negative
B. lactose fermenting
C. non-spore forming
D. coccus Correct Answers D. coccus
A helminth is a type of
A. Bacteria
B. Worm
C. Protozoa
D. Crustacean Correct Answers B. Worm
,A transducing phage contains:
A. Ribosomal proteins
B. a piece of bacterial DNA
C. only phage DNA
D. tRNA only Correct Answers B. a piece of bacterial DNA
All bacteria can be probiotics as long as they are in healthy
amounts.
A. True
B. False Correct Answers B. False
An increase in the ___ will decrease the likelihood of infection
A. number of microbes
B. virulence of microbes
C. host immunity Correct Answers C. host immunity
Antigenic shift resulting in pandemic flu strains is possible
because:
A. The flu virus can infect different animals
B. The flu virus has an RNA genome
C. The flu virus genome has many segments
D. The human flu vax is only partially effective
E. A and C Correct Answers E. A and C
antigenic shift is the reason a new flu vax is needed each year
- genome is segmented in diff ppl
, Bacteria are:
A. Prokaryotes
B. Eukaryotes Correct Answers A. Prokaryotes
- same family as archaea
Blood Brain Barrier (BBB) Correct Answers Cellular structure
prevents bacteria and large molecules from entering brain.
Water, Oxygen, CO2, Glucose, Alcohol and sometimes viruses
get through.
Clostridium botulinum produces a neurotoxin, which can cause:
A. neurospasms
B. increased muscle tone
C. progressive flaccid paralysis
D. death
E. Both C and D Correct Answers E. Both C and D
Coliforms are members of the family that __.
A. Staphylococcacaea, ferment lactose
B. Staphylococcaceae, ferment mannitol
C. Enterobacteriaceae, ferment lactose
D. Enterobacteriaceae, ferment sorbitol Correct Answers C.
Enterobacteriaceae, ferment lactose
Encephalitis symptoms Correct Answers headache, fever,
cerebral dysfunction, disordered thought patterns, and, often,
seizures