04-30-2008, 06:37 PM
42.
The answer is a
. factor is a bacterial protein that can associate with and become a subunit of bacterial RNA polymerase. . factor confers
specificity of initiation on the core enzyme. In the presence of . factor, RNA polymerase chooses the correct strand of duplex DNA for transcripÂtion and initiates transcription at the appropriate promoter region. In some bacteria, such as Bacillus subtilis, a specific . factor is synthesized to change transcriptional selectivity and effect cellular changes like sporulation.
43.
The answer is d.
The deadly mushroom A. phalloides has several toxins. A major toxin is .-amanitin, an octapeptide that inhibits mRNA synthesis by very tightly binding RNA polymerase II (DNA-dependent RNA polymerase). As little as one of the mushrooms (know as the death-cap, death-cup, or avenging angel) delivers a lethal dose of about 10 mg .-amanitin. Severe, irreversible liver damage occurs quickly, leading to death. At higher concentrations, the toxin can inhibit RNA polymerase III and tRNA synthesis. Polymerase I is unaffected. Since .-amanitin is effecÂtive at concentrations of 10.9 to 10.8 M, it has been useful as a research tool for studying RNA polymerase function.
The answer is a
. factor is a bacterial protein that can associate with and become a subunit of bacterial RNA polymerase. . factor confers
specificity of initiation on the core enzyme. In the presence of . factor, RNA polymerase chooses the correct strand of duplex DNA for transcripÂtion and initiates transcription at the appropriate promoter region. In some bacteria, such as Bacillus subtilis, a specific . factor is synthesized to change transcriptional selectivity and effect cellular changes like sporulation.
43.
The answer is d.
The deadly mushroom A. phalloides has several toxins. A major toxin is .-amanitin, an octapeptide that inhibits mRNA synthesis by very tightly binding RNA polymerase II (DNA-dependent RNA polymerase). As little as one of the mushrooms (know as the death-cap, death-cup, or avenging angel) delivers a lethal dose of about 10 mg .-amanitin. Severe, irreversible liver damage occurs quickly, leading to death. At higher concentrations, the toxin can inhibit RNA polymerase III and tRNA synthesis. Polymerase I is unaffected. Since .-amanitin is effecÂtive at concentrations of 10.9 to 10.8 M, it has been useful as a research tool for studying RNA polymerase function.