B250C MODULE 3 EXAMINATION TEST 2026
COMPREHENSIVE STUDY GUIDE
◉ dry heat methods of sterilization. Answer: - Bunsen burners
(1870 C)
- incincerators (800-6500 C)
- hot-air oven (150-180 C for 2-4 hours)
◉ what temperatures can preserve cultures of bacteria, viruses, and
fungi for long periods of time?. Answer: -70 to -135 C
◉ what are some examples of pathogens that can survive months in
the refrigerator. Answer: - S. aureus
- Clostridium species
- Streptococcus species
◉ does desiccation kill all microbes or endospores?. Answer: no, it
only controls growth
,◉ how is lyophilization effective for controlling microbial growth?.
Answer: - it combines cold temperatures with desiccation and
causes less damage/better preserves than desiccation
- prevents formation of ice crystals
◉ what species of bacteria die after a few hours of air drying?.
Answer: - S. pneumoniae
- N. gonorrhoeae
◉ what species of bacteria can remain viable through desiccation?.
Answer: Bacillus, Clostridium, staphylococci species, streptococci
species
◉ what types of radiation can be used to kill microbes or inhibit
growth?. Answer: ionizing radiation (x-rays, gamma rays, high-
energy electron beams)
nonionizing radiation (UV rays)
,◉ what are the effects of ionizing radiation?. Answer: strong enough
to enter cells, introduce ds DNA breaks which can cause mutations -
> most likely lead to cell death
◉ Which types of radiation can be used on packaging and paper?.
Answer: x-rays and gamma rays (types of ionizing radiation)
◉ Which type of radiation is used to sterilize materials that cannot
be autoclaved?. Answer: ionizing radiation (can sterilize plastics or
other heat-sensitive materials)
◉ Which type of ionizing radiation is used to sterilize food in
Europe?. Answer: gamma radiation
◉ How is nonionizing radiation different from ionizing radiation?.
Answer: uses less energy
◉ Which type of radiation is often used for purifying water?.
Answer: UV rays (type of nonionizing radiation)
◉ Can UV rays penetrate surfaces like plastic or glass?. Answer: no,
so cells must be directly exposed to the light source
, ◉ What is the order of ionizing radiation from most to least
penetrating?. Answer: gamma -> x-rays -> cathode rays
◉ What can be destroyed by UV light?. Answer: fungal cells and
spores, bacterial vegetative cells, protozoa, viruses (killed by
increasing time of exposure)
◉ _______ removes microbes from air and liquid. Answer: filtration
◉ What are some examples of common filter materials?. Answer:
cellulose acetate, polycarbonate, plastics, charcoal, diatomaceous
earth, unglazed porcelain
(all with carefully controlled pore sizes, so some can trap viruses
and large proteins)
◉ What can be captured by a HEPA air filter?. Answer: bacterial
cells, endospores, and many viruses
◉ What are the desired qualities in a microbicidal chemical?.
Answer: (not all can be fulfilled by single chemical)
- rapid action at low concen.
- solubility in h2o or alcohol and long-term stability
- broad-spectrum action w/o toxicity for human/animal tissue
COMPREHENSIVE STUDY GUIDE
◉ dry heat methods of sterilization. Answer: - Bunsen burners
(1870 C)
- incincerators (800-6500 C)
- hot-air oven (150-180 C for 2-4 hours)
◉ what temperatures can preserve cultures of bacteria, viruses, and
fungi for long periods of time?. Answer: -70 to -135 C
◉ what are some examples of pathogens that can survive months in
the refrigerator. Answer: - S. aureus
- Clostridium species
- Streptococcus species
◉ does desiccation kill all microbes or endospores?. Answer: no, it
only controls growth
,◉ how is lyophilization effective for controlling microbial growth?.
Answer: - it combines cold temperatures with desiccation and
causes less damage/better preserves than desiccation
- prevents formation of ice crystals
◉ what species of bacteria die after a few hours of air drying?.
Answer: - S. pneumoniae
- N. gonorrhoeae
◉ what species of bacteria can remain viable through desiccation?.
Answer: Bacillus, Clostridium, staphylococci species, streptococci
species
◉ what types of radiation can be used to kill microbes or inhibit
growth?. Answer: ionizing radiation (x-rays, gamma rays, high-
energy electron beams)
nonionizing radiation (UV rays)
,◉ what are the effects of ionizing radiation?. Answer: strong enough
to enter cells, introduce ds DNA breaks which can cause mutations -
> most likely lead to cell death
◉ Which types of radiation can be used on packaging and paper?.
Answer: x-rays and gamma rays (types of ionizing radiation)
◉ Which type of radiation is used to sterilize materials that cannot
be autoclaved?. Answer: ionizing radiation (can sterilize plastics or
other heat-sensitive materials)
◉ Which type of ionizing radiation is used to sterilize food in
Europe?. Answer: gamma radiation
◉ How is nonionizing radiation different from ionizing radiation?.
Answer: uses less energy
◉ Which type of radiation is often used for purifying water?.
Answer: UV rays (type of nonionizing radiation)
◉ Can UV rays penetrate surfaces like plastic or glass?. Answer: no,
so cells must be directly exposed to the light source
, ◉ What is the order of ionizing radiation from most to least
penetrating?. Answer: gamma -> x-rays -> cathode rays
◉ What can be destroyed by UV light?. Answer: fungal cells and
spores, bacterial vegetative cells, protozoa, viruses (killed by
increasing time of exposure)
◉ _______ removes microbes from air and liquid. Answer: filtration
◉ What are some examples of common filter materials?. Answer:
cellulose acetate, polycarbonate, plastics, charcoal, diatomaceous
earth, unglazed porcelain
(all with carefully controlled pore sizes, so some can trap viruses
and large proteins)
◉ What can be captured by a HEPA air filter?. Answer: bacterial
cells, endospores, and many viruses
◉ What are the desired qualities in a microbicidal chemical?.
Answer: (not all can be fulfilled by single chemical)
- rapid action at low concen.
- solubility in h2o or alcohol and long-term stability
- broad-spectrum action w/o toxicity for human/animal tissue
