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.

2. Choose the wrong one from the following statements about bacteria. (A) In alpha-hemolysis, a green zone (incomplete hemolysis) was observed around a bacterial colony on blood agar. (B) Purple sulfur bacteria oxidize hydrogen sulfide to sulfur and are usually photolithoautotrophs. (C) Methylotrophs are proteobacteria that use one-carbon compounds as carbon and energy sources. (D) Nitrifying bacteria can oxidize either ammonium to nitrite or nitrate. (E) Members of the Staphylococcus genus are Gram-negative aerobic bacteria.

3. Please choose the correct statement from comparison among Bacteria, Archaea and Eukarya. (A) Both Archaea and Eukarya contain membrane-enclosed nucleus with nucleolus. (B) Gas vesicles are present in Eukarya, but not in Bacteria and Archaea. (C) Chemolithotrophy is only present in Bacteria, but is absent in Archaea and Eukarya. (D) Bacteria are sensitive to rifampicin, but Archaea are insensitive to rifampicin. (E) The cell wall of Bacteria and Archaea contain muramic acid, which is absent in Eukarya cell wall.

4. Which is correct regarding bacterial infections and diseases? (A) Yersinia pestis is a Gram-positive bacterium to cause plague. (B) Toxoid is used to describe the condition caused by bacterial toxins in the blood of the host. (C) Legionnaires' disease is caused by bacteria transmitted by arthropods. (D) Enterotoxic E.coli (ETEC) can penetrate and multiply within the intestinal epithelial cells to cause diarrhea. (E) Botulism is caused by ingesting the botulinum AB neurotoxin, not bacterial cells.

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.

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

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

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