Which part of the prokaryote RNA polymerase holoenzyme is involved with recognizing promoters specific to certain types of genes?
In prokaryotes, RNA polymerase can bind "naked" sequences upstream of promoters. Eukaryotes need protein "decorations" to facilitate RNA polymerase binding. What is the name of these proteins which assist RNA polymerase with binding?
|A)||TATA box proteins|
When the human genome was first sequenced, scientists expected to find around 100,000 genes (which corresponded to the estimated number of different proteins in a human). Upon its completion and analysis of reading frames, they discovered the number was more likely 25,000. What is the most likely explanation for this?
Which is responsible for the production of a peptide bond between adjacent amino acids during translation?
|A)||Peptidyl transferase activity of the large subunit.|
|B)||Proteins in the large and small subunit of the ribosome.|
|C)||Ribozyme activity of tRNA.|
|D)||The charging effect of aminoacyl tRNA synthetase.|
|E)||Condensase activity of the small subunit.|
The central dogma of molecular biology states that DNA is transcribed to make mRNA, which is translated to make a protein.
Which of the following pieces of evidence is among the strongest that supports the idea that all organisms have arisen from a single distant ancestor?
|A)||All organisms use DNA to store their information.|
|B)||The genetic code is semi-conservative.|
|C)||The code is universal. Genes can be transferred from one organism to another and can be successfully expressed in their new host|
|D)||DNA encodes information for RNA, which directs protein synthesis.|
|E)||The genetic code is degenerate but specific.|
The region of a gene which "tells" RNA polymerase where the genetic message is located is called the
Regarding gene expression, which of these accurately distinguish prokaryotes from eukaryotes?
|A)||Nucleotides in the promoter are different in prokaryotes and eukaryotes.|
|B)||Genes are more widely-spaced apart in eukaryotes than prokaryotes.|
|C)||Prokaryotic ribosomes look different than eukaryotic ones.|
|D)||Prokaryotic ribosomes translate mRNA transcripts that are still being synthesized by RNA polymerase.|
|E)||Prokaryotic mRNA does not contain introns.|
How might a molecular biologist most easily purify mRNA from all the other kinds of RNA in a eukaryotic cell?
|A)||She could create a filter covered with long poly-T sequences and run a cell extract over it. The tails of mRNA would base-pair with the filter and be retained, while all the other types of RNA would be rinsed off.|
|B)||Samples could be spun in a high speed centrifuge. The resulting pellet would contain only mRNA.|
|C)||The sequenced genome can be analyzed and all the regions that encode protein could be used to make synthetic mRNA for analysis.|
|D)||The methyl-G cap could be magnetized and made to adhere to a pellet in a test tube.|
|E)||After splicing, the mRNA becomes short enough to make it distinguishable from other RNA in the cell. These could be filtered out.|
If pre-mRNA is hybridized with mature mRNA, regions loop out and can be viewed with an electron microscope. What do the looped out regions represent?
|B)||Introns to be excised later.|
|C)||Exons in the pre-mRNA.|
|D)||Exons that are in the process of being fused together.|
|E)||Regions of the poly-A tail in the pre-mRNA.|
Connection of an amino acid to a tRNA is a spontaneous reaction.
"Wobble" pairing is largely responsible for
|A)||the redundancy of the genetic code.|
|B)||conservation of the genetic message.|
|C)||the large variety of amino acids encoded by the genetic code.|
|D)||the excess of different kinds of tRNA that are required for all the amino acids.|
|E)||connection of an amino group to a carboxyl group during peptide bond formation.|
A nonsense mutation typically involves
|A)||confusion of which amino acids go where in the polypeptide chain.|
|B)||expansions of the ends of chromosomes due to repeated nucleotides.|
|C)||inappropriate termination of translation early in the "reading frame".|
|D)||duplication of a region of a chromosome.|
|E)||a mistake that causes a portion of a chromosome to "flip" in orientation.|
The area on a tRNA molecule which connects to a specific mRNA molecule is called
|E)||a start codon.|
Which of the following is a nucleic acid found in ribosomes and is an important building block of ribosomes?
Which of these is a ribosomal binding site?
|E)||1, 2, and 3 are all ribosomal binding sites|