9. Which of the following protects bacteria from lysis in dilute solutions and helps to determine their cellular morphology or shape?
(A) Plasma membrane
(B) Peptidoglycan
(C) Capsule
(D) Gas vacuoles
(E) Flagella

5. Choose a correct statement related to antimicrobial chemotherapy. (A) Fluoroquinolones block bacterial DNA replication, by inhibiting DNA gyrase and topoisomerase II. (B) Tetracyclines are antibacterial drugs that can inhibit the synthesis of peptidoglycans, the important component of bacterial cell wall. (C) Penicillins are bactericidal by inhibiting bacterial cell membrane synthesis. (D) Cephalosporins are a class of beta-lactam antibiotics and can disrupt bacterial protein synthese. (E) The Bradford assay is commonly used to measure antimicrobial activity of an antibacterial drug.

6. What is the most convincing reason why "protists" are not considered to be a taxonomic group? (A) They are not cellular life forms. (B) They are too small to be included among the eukaryotes. (C) The group includes both prokaryotic and eukaryotic cell types. (D) The organisms often included in this group are very diverse and don't form a cohesive taxon. (E) They are present in diverse environments.

7. You discover a new microbe while working on a biological project. The microbe is taken to a lab that specializes in placing organisms in their correct phylogenic niche. In order to determine its evolutionary relatedness to other microbes, the lab carries out ______. (A) Small subunit rRNA (SSU rRNA) analysis (B) microscopic analysis (C) biochemical tests (D) DNA fingerprinting (E) mass spectrometry analysis

8. Small internal cell structures are best visualized with a ______. (A) light microscope (B) dark-field microscope (C) transmission electron microscope (D) scanning electron microscope (E) fluorescence microscope

10. Motile bacteria have been placed in an environment with a gradient of a chemical attractant. Which of the following behaviors would you predict? (A) The bacteria will randomly switch back and forth between runs and tumbles. (B) The bacteria will only exhibit runs away from the chemical. (C) The bacteria will reduce tumbling frequency. (D) The bacteria will reduce run duration in the direction of the chemical. (E) The bacteria will both reduce tumbling frequency and increase run duration in the direction of the chemical.

11. You are studying a newly discovered prokaryotic microorganism and are attempting to determine whether it will be classified in the domain Bacteria or in the domain Archaea. All of the following would be helpful in making that distinction except ______. (A) sequence of small subunit ribosomal RNA (B) type of membrane lipids (C) presence or absence of peptidoglycan in cell walls (D) presence or absence of double-stranded circular DNA genome (E) the assembly of flagella

12. At 4:00 p.m. a closed flask of sterile broth is inoculated with 10,000 cells. The lag phase lasts 1 hour. At 9:00 p.m. the log phase culture has a population of approximately 41 million cells. The mean generation time is calculated as ______. (A) 10 minutes (B) 20 minutes (C) 30 minutes (D) 40 minutes (E) 60 minutes

13. A microbiologist is trying to isolate a pathogen expected to be present in very small numbers from a stool specimen in which there are abundant normal microbiota. Which strategy would most likely accomplish this purpose? (A) Culture on enriched media (B) Culture on differential media (C) Culture in an anaerobe jar (D) Culture on selective agar followed by enrichment culture (E) Enrichment culture followed by culture on selective agar

14. Which of the following does not inhibit protein synthesis? (A) Tetracycline (B) Streptomycin (C) Penicillin (D) Erythromycin (E) Chloramphenicol

15. Which of the following is not true of coronaviruses? (A) Coronaviruses contain envelope (B) Coronaviruses are negative-sense single-stranded RNA viruses. (C) Coronaviruses infect humans (D) Coronaviruses infect mammals (E) Coronaviruses infect avian species