Microbiology: Chapter 8

Heat can quickly  denatures proteins, may damage the membrane by making it more fluid and denature DNA and RNA 

• True

• False

A good example of dry is flaming a loop used to transfer bacteria to a petri plate 

• True

• False

Dessication may help to stop growth, but doesn't necessarily kill bacteria. 

• True

• False

Match the term to the definition: Sterilization 

• The complete destruction of all microbes on an object

• The reduction or inhibition of microbial growth on non-living surface

• The reduction or inhibition of microbial growth on living tissue

Bacteria tend to die at a fixed exponential rate, meaning X^2(squared) 

• True

• False

Match the term to the definition: Disinfection 

• The complete destruction of all microbes on an object

• The reduction or inhibition of microbial growth on non-living surface

• The reduction or inhibition of microbial growth on living tissue

Many endospores are resistant to dessication 

• True

• False

Which of these is most popular in sterilizing culture media and lab instruments?

• Autoclaving

• Dry heat

• Purell

• Antiseptics

Dry heat kills by oxidizing and can...

• Denature protein and DNA

• Slow the growth of bacteria

• Inhibits growth of new bacteria

Freeze drying also called lyophilizaiton is the...

• Simultaneous combination of freezing and heating

• Simultaneous combination of freezing and addition of water

• Simultaneous combination of freezing and dessication

Match the term to the definition: Antisepsis 

• The complete destruction of all microbes on an object

• The reduction or inhibition of microbial growth on non-living surface

• The reduction or inhibition of microbial growth on living tissue

Osmotic pressure treatment is the use of ____ and causes _____.

• Salts, freeze drying

• Ice, plasmolysis

• Salts, plasmolysis

COLD does not kill the microorganism but it will _______ bacterial growth.

Halogens are which of these (as it applies to us for this class)

• Earth metals

• Strong oxidizing agents

• Non-earth metals

• Weak oxidizing agents

Pasteurization is the....

• Short duration/high temperature treatment of food (72C for 15 seconds)

• Long duration/low temperature treatment of food (12C for 3 hours)

• Short duration/low temperature treatment of food (12C for 15 seconds)

• Long duration/high temperature treatment of food (72C for 3 hours)

What are two methods of dry heat?

• Incineration (combustion)

• Dry ovens

• Heat lamp

• Natual heat source (sun)

This is a commonly used household disinfectant. 

• Sodium hypochlorite

• Hypochlorous acid

• Hypochlorite

Which of these are reasons to control microbial growth? (Choose all that apply)

• Prevention and treatment of infection

• Prevention of infection

• Is a form of secondary prevention

• Prevention of food spoilage

Match the term to the statement: When chlorine is added to water, what forms is a strong oxidizing agent and disrupts enzymes. 

• Hypochlorite

• Hypochlorous acid

• Compressed chlorine gas

• Bleach

Choose all those that are correct when asking how various agents harm bacteria. 

• Damage to cell wall

• Alteration of membrane permeability

• Damage to proteins and/or nucleic acids

• Controlled by either physical or chemical agents

• All of these

• Only A, B, and C

Filtration is the passage of a liquid through a filter that create a filtrate (microbes), there are membrane filters that can eliminate most bacteria, however,which of these statements is something that is not true of filtration.

• Filters cannot help you obtain toxins that may be present

• Filters can remove toxins that could be present

• Filtration can help to separate microorganisms from a liquid

Boiling water kills most bacteria and viruses but how long does it take to kill each of these?

• 10 minutes for bacteria, 15 minutes for a virus

• 15 minutes for a bacteria, 25 minutes for a virus

• 10 minutes for a bacteria, 20 minutes for a virus

• 5 minutes for bacteria, 20 minutes for a virus

Radiation helps to kill bacteria which of these types of radiation are considered "ionizing" (Choose all that apply)

• Gamma rays

• UV

• Microwaves

• X-Rays

Match the term to this statement: The chemical choice in treatment of swimming pools.

• Hypochlorite

• Hypochlorous acid

• Compressed chlorine gas

• Bleach

Radiation kills bacteria in many ways, one of these is Non-ionizing which can be which of these? (Choose all that apply)

• Gamma rays

• UV

• Microwaves

• X-Rays

This is used in the disinfection of public drinking water and pools (using small quantities such as 1ppm)

• Hypochlorite

• Hypochlorous acid

• Compressed chlorine gas

• Bleach