HW 3 Chapter 4 5 Essay

Submitted By lydiar99
Words: 518
Pages: 3

1. In nature, bacteria
a. often grow in close association with many kinds of organisms.
b. may remain in a prolonged exponential phase.
c. frequently synthesize structures such as slime layers.
d. may adhere to surfaces by means of pili and slime layers.
e. All of the choices are correct.

2. The process of killing or removing all of the microorganisms in or on a material is termed
a. sterilization
b. disinfectation
c. sanitation
d. antisepsis

3. In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the
a. lag phase
b. exponential (log) phase
c. stationary phase
d. decline phase
e. boomer phase

4. Pasteurization
a. is the use of heat to sterilize food products.
b. is the use of heat to reduce numbers of pathogenic/spoilage bacteria in a food item to a safe level.
c. is a process which uses intense cold to kill microorganisms on foods.
d. is a process which uses short bursts of radiation to kill microorganisms on foods.

5. The simplest technique for isolating bacteria in growth media is referred to as the
a. pour plate method.
b. streak plate method.
c. serial dilution method.
d. MPN method.

6. A suffix used to describe a killing action would be
a. -static.
b. -cidal.
c. -cillin.
d. -tion.

7. Prokaryotic cells divide by a process known as
a. conjugation.
b. mitosis.
c. binary fusion.
d. binary fission.

8. A common environmental organism that may even grow in certain chemical disinfectants is
a. Escherichia coli.
b. Streptococcus pneumoniae.
c. Pseudomonas aeruginosa.
d. enveloped virus.

9. Gamma rays cause biological damage in living systems by
a. producing reactive molecules such as superoxide and hydroxyl free radicals.
b. causing tiny gravity sinks and black holes to be formed in the substance.
c. introducing toxins.
d. making the substance radioactive.

10. Which are essentially equivalent treatments?
a. dry 200°C heat for 1.5 hours; wet 121°C heat for 15 minutes
b. dry 160°C heat for 1.0 hour; wet 200°C…