Microbiology - chapter 7
Which is the best method to sterilize heat-labile solutions?
Which best describes the pattern of microbial death?
The cell in a population die at a constant rate
Which chemical agents is used for sterilization
Which substances is used for surgical hand scrubs?
Which of the following antimicrobial control agents statement are TRUE
a) contaminating organic debris such as blood or sputum decrease effectiveness
b) some agents kill by denaturing microbial cell proteins
c) some agents affect microbial cell membranes by dissolving lipids
d) silver is used for treating antibiotic-resistant bacteria
Which of the following does achieve sterilization?
a) dry heat
c) supercritical fluids
d) ethylene oxide
Which of the following does NOT achieve sterilization?
Which is a limitation of the autoclave?
It cannot be used with heat-labile materials
An agent to reduce bacteria on a toilet would be called
Applying heat to living cells can result in
a) breaking of hydrogen bonds
b) alteration of membrane permeability
c) denaturation of enzymes
c) damage to nucleic acids
Which disinfectants act by disrupting the plasma membrane?
All substances are effective against noenveloped viruses
b) ethylene oxide
Which method is used to preserve food ?
Which concentration of ethanol (alcohol) is the most effective bactericide?
All factors contribute to hospital acquired infection
a) some bacteria metabolize disinfectants
b) gram-negative bacteria are often resistant to disinfectants
b) invasive procedures can provide portal of entry for bacteria
d) bacteria my be present in commercial products such as mouthwash
Which of the treatments are the most effective for controlling microbial growth?
a) 63o C for 30 min
b) 72oC for 15 sec
c) 140o C for 4 sec
Which method could be used to sterilize plastic Petri plates in a plastic wrapper?
Which results in lethal damage to nuclei acids?
c) some chemicals
All of the following are effective for destroying PRIONS
b) NaOH + autoclaving at 134oC
All of the following are methods of food preservation
b) high pressure
c) ionizing radiation
d) osmotic pressure
If you were preparing nutrient agar at home and did nota have an autoclave, what could you use to sterilize the nutrient agar?
pressure cooker at 121o C for 15 minutes
Which one of the following is most resistant to chemical biocides?
The thermal death times is the time needed to kill all the bacteria in a particular culture at a certain temperature
Moist heat destroys organisms by denaturing proteins
The PH of the medium has no affect on the activity of the disinfectant being applied
Autoclaving is the most effective method of moist heat sterIlization