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1. Which of the following best describes the pattern of microbial death? A. All

ID: 194554 • Letter: 1

Question


1. Which of the following best describes the pattern of microbial death?
A. All the cells in a culture die at once.
B. The pattern varies depending on the antimicrobial agent.
C. The pattern varies depending on the species.
D. Not all of the cells in a culture are killed.
E. The cells in a population die at a constant rate.


QUESTION 2
Which of the following pairs of terms is mismatched?
A. surfactant — removes microorganisms through polar interactions
B. desiccation – loss of water from cells
C. tincture- alcohol extract of a compound
D. sterile — no infectious particles are present on object
E. bacteriostatic — kills vegetative bacterial cells


QUESTION 3
Controlling bacterial growth is difficult, and often wet heat is the best disinfectant/sterilant. Which of the following is a limitation of the autoclave?
A. It cannot be used with glassware.
B. It cannot kill endospores.
C. It cannot be used with heat-sensitive materials.
D. It requires an excessively long time to achieve sterilization.
E.It cannot inactivate viruses.

QUESTION 4
• Which concentration of ethanol is the most effective bactericide?
A. 100 %
B. 70 %
C. 50 %
D. 40 %
E. 30 %


QUESTION 5
An iodophor is a(n)
A. slow-released iodine mixed with a surfactant.
B. quarternary ammonium compound.
C. form of formaldehyde.
D. phenol.
E. agent that reduces oxygen.


QUESTION 6
• Which of the following are factors that affect microbial death by chemical?
A. Number of microbes to start with
B. The environment the bacteria are in
C. The time of exposure to the chemical
D. The microbe’s own characteristics
E. ALL of these effect death by chemical


Explanation / Answer

1) The cells in a population die at a constant rate - During the death phase of the growth curve the number of viable cells decreases constantly which is opposite of the logarithmic phase. The rate may vary according to the species or antimicrobial agent, but the pattern does not.