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Questions and Answers
The Ames test is used to screen for carcinogenic compounds.
The Ames test is used to screen for carcinogenic compounds.
True
The conventional way to determine if a chemical is carcinogenic is to inject it into animals and look for tumor development.
The conventional way to determine if a chemical is carcinogenic is to inject it into animals and look for tumor development.
True
The Ames test is used to measure the rate of forward mutations in strains of auxotrophic bacteria.
The Ames test is used to measure the rate of forward mutations in strains of auxotrophic bacteria.
False
The Ames test is a cost-effective and efficient way to screen for carcinogenic compounds compared to animal testing.
The Ames test is a cost-effective and efficient way to screen for carcinogenic compounds compared to animal testing.
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All mutagenic agents are also carcinogenic.
All mutagenic agents are also carcinogenic.
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The Ames test uses a strain of Salmonella typhimurium that is auxotrophic for histidine.
The Ames test uses a strain of Salmonella typhimurium that is auxotrophic for histidine.
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The first step in the procedure is to inoculate S. aureus from broth culture onto a nutrient agar plate.
The first step in the procedure is to inoculate S. aureus from broth culture onto a nutrient agar plate.
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The nutrient agar plate is incubated at 37°C for 48 hours.
The nutrient agar plate is incubated at 37°C for 48 hours.
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A sterile colony carrier is used to transfer colonies from the initial S. aureus plate to new plates.
A sterile colony carrier is used to transfer colonies from the initial S. aureus plate to new plates.
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The replica plating technique allows detection of antibiotic-resistant organisms.
The replica plating technique allows detection of antibiotic-resistant organisms.
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The streptomycin agar plate contains $100 \mu g$ of streptomycin per liter of medium.
The streptomycin agar plate contains $100 \mu g$ of streptomycin per liter of medium.
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After inoculating the plates, they are incubated at $37^\circ C$ for 2 to 4 weeks.
After inoculating the plates, they are incubated at $37^\circ C$ for 2 to 4 weeks.
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Ultraviolet radiation is part of the electromagnetic spectrum with longer, lower energy wavelengths than visible light.
Ultraviolet radiation is part of the electromagnetic spectrum with longer, lower energy wavelengths than visible light.
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When DNA absorbs UV radiation at 254 nm, the energy is used to form new covalent bonds between adjacent pyrimidines.
When DNA absorbs UV radiation at 254 nm, the energy is used to form new covalent bonds between adjacent pyrimidines.
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Thymine dimers are the most common type of pyrimidine dimers formed in DNA.
Thymine dimers are the most common type of pyrimidine dimers formed in DNA.
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Escherichia coli uses light repair or photo-reactivation to reverse the formation of pyrimidine dimers in its DNA.
Escherichia coli uses light repair or photo-reactivation to reverse the formation of pyrimidine dimers in its DNA.
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The presence of a few scattered revertants on the negative control plate is due to spontaneous back mutations, which never occur.
The presence of a few scattered revertants on the negative control plate is due to spontaneous back mutations, which never occur.
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Examining the areas beyond the halo on the plate can help detect a faint lawn of bacterial growth.
Examining the areas beyond the halo on the plate can help detect a faint lawn of bacterial growth.
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The UV lamp should be turned off after 30 seconds for all plates.
The UV lamp should be turned off after 30 seconds for all plates.
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Plates 6 and 7 should not be irradiated.
Plates 6 and 7 should not be irradiated.
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All plates should be incubated for 24 to 48 hours at room temperature.
All plates should be incubated for 24 to 48 hours at room temperature.
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Plate 4 should be irradiated for 3 minutes with the lid on and covered with the mask.
Plate 4 should be irradiated for 3 minutes with the lid on and covered with the mask.
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The growth patterns should be recorded on the Data Sheet after incubation.
The growth patterns should be recorded on the Data Sheet after incubation.
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The rate of reversion is determined by counting the number of colonies on histidine-deficient medium.
The rate of reversion is determined by counting the number of colonies on histidine-deficient medium.
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The top agar contains 0.6% agar, 0.5% NaCl, and histidine.
The top agar contains 0.6% agar, 0.5% NaCl, and histidine.
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The histidine in the top agar allows the bacteria to undergo cell division for mutagenesis.
The histidine in the top agar allows the bacteria to undergo cell division for mutagenesis.
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The top agar must be vortexed at high speed for even distribution.
The top agar must be vortexed at high speed for even distribution.
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The chemical agent can be applied directly to the center of the plate or using a filter paper disk.
The chemical agent can be applied directly to the center of the plate or using a filter paper disk.
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If the agent is mutagenic, a halo of scattered colonies will be seen around the disk.
If the agent is mutagenic, a halo of scattered colonies will be seen around the disk.
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