What effect does UV radiation have on bacterial cells?
Ultraviolet light inactivates bacteria by forming pyrimidine dimers in DNA, which can interfere with transcription and replication.
What is the main effect of UV radiation on a bacterial cell quizlet?
UV light damages the DNA of exposed cells by causing bonds to form between adjacent pyrimidine bases, usually thymines, in DNA chains. The thymine dimers inhibit correct replication of the DNA during reproduction of the cell.
What are the possible outcomes of a bacteria exposed to UV light?
Ultraviolet light inactivates microorganisms by forming pyrimidine dimers in RNA and DNA, which can interfere with transcription and replication (Goosen and Moolenaar, 2008; Cutler and Zimmerman, 2011).
What is the effect of radiation on bacteria?
Gram-negative pathogen bacteria are very sensitive to radiation. As expected bacterial spores are more resistant to ionizing radiation than vegetative cells are. Irradiation also reduces the number of mould populations.
How does ultraviolet light destroy bacterial cells quizlet?
UV causes mutation called thymine dimers which put kinks in DNA strands, rendering the molecule useless for transcription. What damage does UV cause which makes it effective in killing bacteria? bacteria can synthesize their own repair enzymes to fix the damages caused by mutagens like UV light.
What effect does exposure to UV radiation have on bacterial cells and cell survival quizlet?
Describe the damaging effects of UV radiation on living cells. UV radiation causes the formation of thymine dimmers in DNA that result in replication errors during reproduction. These error cause gene defects, which ultimately lead to cell death.
How does UV radiation stop bacterial growth quizlet?
How does UV light control bacterial growth? By causing irreplaceable levels of damage to the bacterial cell DNA. Thymine-thymine dimmers which in turn disrupts DNA replication.
What is UV radiation used for in microbiology?
Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short-wavelength ultraviolet (ultraviolet C or UV-C) light to kill or inactivate microorganisms by destroying nucleic acids and disrupting their DNA, leaving them unable to perform vital cellular functions.
How does UV light control bacterial growth?
In simple terms, when bacteria or another type of microbe is directly exposed to certain types of UV light, the DNA (its fundamental building block) of the cell is damaged, preventing it from replicating. If a cell cannot reproduce, then the cell cannot cause infection, which is how UV light kills bacteria.
What is the effect of UV rays in environment?
Effects on the environment Ultraviolet radiation not only affects humans, but wildlife as well. Excessive UV -B inhibits the growth processes of almost all green plants. There is concern that ozone depletion may lead to a loss of plant species and reduce global food supply.
Which of the following is use of ultraviolet radiation?
UV radiation is widely used in industrial processes and in medical and dental practices for a variety of purposes, such as killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy and suntanning.
What are the reactions of bacteria to UV light?
Abstract The UV dose-response behavior of laboratory cultures of waterborne bacteria were examined for UV doses ranging from ca. 0-100 mW.s/cm2 using a collimated-beam reactor. Specific physiological responses measured in these tests included viability (ability to reproduce) and respiration (oxygen uptake rate).
How does UV irradiation affect the DNA molecule?
Except the production of free radicals, UV can directly affect DNA. The most common effect is at locations on the DNA molecule where two thymine (T) bases occur adjacent to each other. UV irradiation causes the two T bases to covalently fuse together.
What makes endospores more resistant to UV light?
Endospores are more resistant to UV light than vegetive cells -DNA of endospores is protected by small acid-soluble proteins that bind to DNA and alter is conformation, thereby protecting it from photochemical damage What limited protection do cells have against the damaging effects of UV radiation?
Which is the best survival phase after exposure to UV?
Explain. the stationary phase would have the best survival after exposure to UV because many of the bacterium would have formed endospores. what is the purpose of inoculating a control plate in this experiment (Lethal effects of temperature – LE 16) To ensure viability of organism