The inactivation of one X chromosome is established by the directed spreading of heterochromatin. The silent state of this chromosome is _______________ in the subsequent cell divisions
(a) completed
(b) switched
(c) erased
(d) maintained
(d)
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A recent study compared the Homo sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history
Additional data consistent with this hypothesis could be the discovery of _____. A) some Neanderthal sequences not found in living humans B) a few modern H. sapiens with some Neanderthal sequences C) duplications of several Neanderthal genes on a Neanderthal chromosome D) some Neanderthal chromosomes that are shorter than their counterparts in living humans
Very early in development, each cell is capable of expressing all its genes. This is referred to as
A. determination. B. specification. C. bipotential induction. D. totipotency. E. multipotency.
A recessive allele is one
A) that produces no effect when present in the homozygous condition. B) that is not expressed as strongly as a dominant allele. C) that must be lethal in the homozygous condition. D) whose effect is masked when paired with a dominant allele. E) that appears only in a heterozygote.
Which of the following accurately describes transcriptional control of gene expression in eukaryotes?
a. Activators trigger sequences of DNA transcription factors to be expressed b. Dependent on interactions of mRNA sequences with ribosomes c. Promoters help transcription factors bind to RNA polymerases d. Transcription factors help RNA polymerase bind to promoter sequences