Biology Chapter 6- Micro

Which of the following is an advantage of the direct microscopic count? A. can readily count organisms that are motile B. can easily distinguish live from dead cells C. requires no incubation time D. sample volume is unknown E. requires a large number of cells

In Figure 6.1, which line best illustrates the growth of a facultative anaerobe incubated aerobically? Selected Answer: A. a B. b C. c

hirty-six colonies grew in nutrient agar from 1.0 ml of undiluted sample in a standard plate count. How many cells were in the original sample? A. 4 B. 9 C. 18 D. 36 E. 72

Most fungi grow best at pH A. 1. B. 5. C. 7. D. 9. E. 14.

In Figure 6.3, which tube shows the expected growth pattern for a facultative anaerobe? A. a B. b C. c D. d E. e

Which of the following is an advantage of the standard plate count? A. can readily count cells that form aggregates B. determines the number of viable cells C. can be performed on very dilute samples, such as lake water D. provides immediate results E. can be used to count heat-sensitive bacteria

In Figure 6.1, which line shows the growth of an obligate aerobe incubated anaerobically? A. a B. b C. c

The term aerotolerant anaerobe refers to an organism that A. does not use oxygen but tolerates it. B. is killed by oxygen. C. uses oxygen or grows without oxygen. D. requires less oxygen than is present in air. E. requires more oxygen than is present in air.

In one hospital, Pseudomonas aeruginosa serotype 10 infected the biliary tract of 10 percent of 1300 patients who underwent gastrointestinal endoscopic procedures. After each use, endoscopes were washed with an automatic reprocessor that flushed detergent and glutaraldehyde through the endoscopes, followed by a tap water rinse. P. aeruginosa 10 was not isolated from the detergent, glutaraldehyde, or tap water. What was the source of the infections? A. bacterial cell walls in the water B. a biofilm in the reprocessor C. contaminated disinfectant D. fecal contamination of the bile ducts E. None of the answers is correct.

Salts and sugars work to preserve foods by creating a A. depletion of nutrients. B. hypotonic environment. C. lower osmotic pressure. D. hypertonic environment. E. lower pH.

The term aerotolerant anaerobe refers to an organism that A. does not use oxygen but tolerates it. B. is killed by oxygen. C. uses oxygen or grows without oxygen. D. requires less oxygen than is present in air. E. requires more oxygen than is present in air.

hree cells with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours? A. 900 B. 180 C. 96 D. 32 E. 15

Most bacteria grow best at pH A. 1. B. 5. C. 7. D. 9. E. 14.