WorksheetsChapter 15
Total questions: 10
Worksheet time: 5mins
An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell?
RNA polymerase attaches to the regulator.
The repressor protein attaches to the regulator.
Allolactose binds to the repressor protein.
The repressor protein and allolactose bind to RNA polymerase.
Allolactose binds to the regulator gene.
Genomic imprinting, DNA methylation, and histone acetylation are all examples of
chromosomal rearrangements.
karyotypes.
genetic mutation.
translocation.
epigenetic phenomena.
The tryptophan operon is a repressible operon that is
turned off whenever tryptophan is added to the growth medium.
turned on only when tryptophan is present in the growth medium.
turned on only when glucose is present in the growth medium.
turned off only when glucose is present in the growth medium.
permanently turned on.
In eukaryotes, general transcription factors
bind to other proteins or to a sequence element within the promoter called the TATA box.
are required for the expression of specific protein-encoding genes.
usually lead to a high level of transcription even without additional specific transcription factors.
inhibit RNA polymerase binding to the promoter and begin transcribing.
bind to sequences just after the start site of transcription.
The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called
RNA targeting.
RNA blocking.
RNA obstruction.
RNA interference.
RNA disposal.
Which of the following best describes siRNA?
a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
a molecule, known as Dicer, that can degrade other mRNA sequences
a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns
DNA microarrays have had a huge impact on genomic studies because they
allow physical maps of the genome to be assembled in a very short time.
can identify the function of any gene in a genome.
can be used to introduce entire genomes into bacterial cells.
dramatically enhance the efficiency of restriction enzymes (endonucleases).
allow the expression of many or even all of the genes in a genome to be compared at once.
Which one of the following techniques involves reverse transcriptase, PCR amplification, and gel electrophoresis?
nucleic acid hybridization
RNA interference
in situ hybridization
DNA microarray assays
RT-PCR
A lack of which molecule would result in the cell's inability to 'turn off' genes?
ubiquitin
operon
promoter
corepressor
inducer
The lactose operon is likely to be transcribed when
the cyclic AMP and lactose levels are both high within the cell.
the cyclic AMP levels are low.
there is glucose but no lactose in the cell.
there is more glucose in the cell than lactose.
the cAMP level is high and the lactose level is low.
