How does the SOS system simultaneously fix damage DNA and increase the mutation rate? How does the SOS system increase the survival of microorganisms?
What will be an ideal response?
Answer: The SOS system causes the expression of a number of proteins, and specifically DNA polymerases, that fix lesions in DNA molecules but are prone to errors or do not use templates at all to synthesize new DNA. This allows the organism to survive DNA damage by fixing large lesions or breaks in the DNA but also results in mutations. Even under some conditions that do not result in a lot of DNA damage, the SOS system proteins can increase mutation rate. A slight increase in mutation rate may increase the probability of an advantageous mutation in one cell (even if many other cells are disadvantaged or killed by mutations). The cell with the advantageous mutation would be better able to survive the stress and could go on to replicate and take over the population, thus increasing the survival of the microorganism.
You might also like to view...
In reabsorption,
a. plasma proteins are returned to the blood. b. excess hydrogen ions are removed from the blood. c. excess water is passed on to the urine. d. nutrients and salts are selectively returned to the blood. e. drugs and foreign substances are passed into the urine.
The vegetation of tundra is dominated by
A) broadleaf deciduous trees. B) short plants such as sedges, heaths, and willow. C) needle-leaf evergreen trees. D) sclerophyllous broadleaf evergreen shrubs.
You might have been accidentally exposed to an insecticide while working in a citrus grove. What symptoms of poisoning would you watch for?
A) depression B) Alzheimer's disease C) muscle tremors D) excessive urination
List the 3 parts that make up one nucleotide: