Studied by 2 people
A transfer tRNA (1) attached to the amino acid lysine enters the ribosome. Lysine binds to the growing polypeptide on tRNA2. Where does tRNA2 move to.
E site
In eukaryotic cells, transcription can not begin until
several transcription factors have bound to the promoter
The anticodon of a particular tRNA molecule is
complementary to the corresponding mRNA codon
Which of the following is not true of RNA splicing?
Exons are cut out before mRNA leaves the nucleus
Which component is not directly involved in translation
DNA
which of the following statements correctly describes the role of a molecule that controls a repressible operon
The molecule binds to the repressor protein and activates it
The tryptophan operon in some bacteria is a repressible operon. which of the following statements correctly describes this operon?
It is deactivated whenever tryptophan is added to the growth medium
which of the following is a protein product of a regulatory gene?
repressor
a lack of which of the following molecules would result in the cell’s inability to”turn off” genes?
corepressor
What would be the result of a mutation that deactivates the the regulatory gene of a repressible operon in an E. coli cell?
continuous transcription of the enzyme-coding gene controlled by that regulator
which of the following environments would most likely lead to the transcription of the lactose operon?
The cyclic AMP levels and lactose levels are both high within the cell
When the substrate of a metabolic pathway is present in a bacterial cell, which of the following processes will occur?
transcription of the genes in an inducible operon
which of the following must occur in order for a repressible operon to be transcribed
RNA polymerase and the active repressor must be inactive
In positive control of several-sugar-metabolism related operons, the cAMP receptor protein (CRP) binds to DNA to stimulate transcription. which of the following activates CRP?
decrease in glucose and increase in cAMP
A type of mutation in bacteria in the repressor results in a molecule known as the super-repressor because it represses the lac operon permanently. which of the following processes would occur in such a mutant?
the repressor protein cannot bind the inducer
which of the following mechanisms is used to coordinate the expression of multiple, related genes in eukaryotic cells?
A specific combination of control elements in each gene’s enhancer coordinates the simultaneous activation of the genes.
What effect does methylation have on DNA
It makes it transcriptionally inactive
which of the following statements correctly describes the role of histone acetylation and DNA methylation in gene regulation
DNA methylation reduces transcription, and histone acetylation promotes transcription
which of the following statements correctly describes the role of general transcription factors in eukaryotes?
They bind to other proteins or to a sequence element within the promoter called the TATA box
Transcription factors in eukaryotes usually have DNA-binding domains as well as other domains that are specific for binding other molecules. In general, which of the following would you expect many of them to be able to bind?
other transcription factors
Gene expression might be altered based on post-transcriptional processing in eukaryotes rather than prokaryotes. which of the following statements describes this difference.
Eukaryotic exons may be spliced in alternative patterns
which of the following statements describes one of the functions of the protein called ubiquitin?
it attaches to proteins that are marked for destruction in the cell
Gene expression is blocked by a process called RNA interference. which of the following molecules is involved in this process
siRNA
which of the following best describes siRNA
a short-double stranded RNA, one of whos strands can block gene expression
Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease gene, which of the following results would be likely?
Beta galactosidase would not be produced
Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following results would likely occur when the cell is exposed to lactose?
The 3 genes of the operon will be transcribed continuously
A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments she succeeded in decreasing methylation of histone tails. which of the following results would she most likely see?
Decreased chromatin condensation
If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then
The repressor is active in the absence of the amino acid
The functioning of enhancers is an example of
transcriptional control of gene expression
Which statement about DNA in one of your brain cells is true?
It is the same as the DNA in one of your liver cells
Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to
cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme
What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform the bacteria with a recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes III. Extract Plasmid DNA from bacterial cells IV. Hydrogen-bond the plasmid DNA to nonplasmid DNA fragments V. Use ligase to seal plasmid DNA to nonplasmid DNA
III, II, IV, V, I
Why is it so important to be able to amplify DNA fragments when studying genes?
A gene may represent only a millionth of a cell’s DNA
The reason for Taq polymerase for PCR is that
it is heat stable and can withstand the heating step of PCR
In a genome-wide expression study using a DNA microarray assay, each well is used to detect the
Expression of a specific gene by a cell
which of the following techniques involves reverse transcriptase, PCR amplification, and gel electrophoresis?
RT-PCR
which of the following would not be true of cDNA produced using human brain tissue as the starting material
It would contain sequences representing all genes in the genome
