________ in Drosophila results from the movement of the transcriptionally active w+ allele into the centromeric heterochromatin region of the fruit-fly X chromosome
Fill in the blank(s) with correct word
Position effect variegation (PEV)
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If you were to observe the activity of methylated DNA, you would expect it to _____
A) be replicating nearly continuously B) be unwinding in preparation for protein synthesis C) have turned off or slowed down the process of transcription D) be very actively transcribed and translated E) induce protein synthesis by not allowing repressors to bind to it
Which of the following statements about generalized transduction is false?
A. "Head full" packaging always places only phage DNA into the phage head during phage packaging in generalized transduction. B. Generalized transduction always involves lytic phage. C. Generalized transduction can be used to map bacterial genes. D. Genes that are close together on the bacterial chromosome will have a relatively large cotransduction frequency. E. Two recombination events are necessary to integrate the transferred DNA during generalized transduction.
If an individual is heterozygous at two loci (A b / a B) that are located on the same chromosome arm with A closer to the centromere than B, under what conditions would a crossover in a somatic cell generate a twin spot?
A) The crossover would have to occur between the A locus and the centromere and involve two homologous, nonsister chromatids. B) The crossover would have to occur between the A locus and the B locus and involve two homologous, nonsister chromatids. C) The crossover would have to occur between the B locus and the end of the chromosome and involve two homologous, nonsister chromatids. D) A double crossover would have to occur, with one crossover between the A locus and the centromere and a second crossover between the A and B loci, and both crossovers would have to involve two homologous, nonsister chromatids. E) No crossover in a somatic cell could generate a twin spot.
What is the basic structure of most lipids?
A) A glycerol head and up to three fatty acid tails B) A linear chain of individual monomers C) A branched chain of individual monomers D) A chain of fatty acid tails