Solved by a verified expert:Question 16Which of the following statements about CpG islands is correct?a) Methylated CpG islands is associated with long term gene repression.b) The CpG island methylation is universal across both prokaryotes and eukaryotes.c) There is an association between DNA methylation at the CpG island and acetylation of histones via recruitment of acetylases.d) Transcriptionally active DNA has higher frequency of methylated CpG.e) CpG islands are commonly found at the 3? UTR regions.Question 18A mutation in the gene for the yeast regulatory protein GAL4 causes yeast to grow poorly on galactose. What is the function of GAL4?a) It is a substrate that binds and activates a transcriptional activator.b) It is an enzyme that metabolizes galactose.c) It is a product that binds and activates a transcriptional repressor.d) It is a transcription activator for the galactose-digesting enzyme gene. e) It is a transcription repressor that prevents expression of yeast galactose-digesting enzymes.Question 22Although operons are not common in eukaryotes, eukaryotic genes may be activated by the same stimulus. Which of the following DNA regulatory sequences make this coordinated gene expression possible?a) TATA boxesb) Transcription factor binding sitesc) Core promotersd) Splicing donor and acceptor sitese) Insulator elementsQuestion 24A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n)a) silencer.b) repressor.c) insulator.d) mediator.e) enhancer.Question 25Which of the following generally get transcribed constitutively (at all times, in all cells)?A) Regulatory genes b) Structural genes c) Promoter elements d) Operator elements e) OperonsQuestion 26An example of a gene product encoded by a regulatory gene isa) repressor protein.b) an operator.c) beta-galactosidase enzyme. d) a terminator. e) allolactose.Question 27The formation of 1+2 and 3+4 secondary structures that cause attenuation in the 5? UTR region of mRNAs from the trp operon is triggered when____ a) the repressor protein fails to bind to the operator. b) there is a spontaneous mutation introduced into the 5? UTR. c) the tryptophan level inside the bacterial cell is high. d) the transcription of the protein-coding sequences within the trp operon is initiated. e) the tryptophan level inside the bacterial cell is extremely low.Question 29When a gene is under positive inducible control, what would be the result of a mutation that eliminates the activator protein?a) The mutation will lead to activation of a repressor, which will block transcription.b) More cAMP will be produced to compensate for the lack of the activator protein.c) Transcription of the gene will be greatly reduced or turned off.d) The transcription of the gene will not be affected, as an activator is not required in positive induction. e) The gene becomes expressed all the time and at high levels due to the lack of activation.Question 30Which of the following statements about DNA binding protein is FALSE ?a) Specific amino acids within the motif form hydrogen bonds with DNA.b) These proteins usually bind DNA through the major groove.c) Most DNA binding proteins bind dynamically.d) Once bound, most of DNA binding proteins remain on DNA permanently.e) These proteins can affect the expression of a gene.Question 32Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. The man has fathered a child with a woman that does not have freckles. What is the probability that their child has freckles? a) 2/3 b) 1/4 c) 1/3 d) 3/4 e) 1/2
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