Exam 13: The Genetic Code and Transcription

Write a sequence of mRNA that codes for five amino acids and the mRNA should contain proper punctuation and polarity.

The finding that virtually all organisms use the same genetic code provides the basis for declaring that the code is universal.Name at least two exceptions to such universality.

An intron is a section of _________ .

Describe how rho- dependent termination occurs in bacteria.

Which of the following bacterial RNA polymerase subunits is found in the holoenzyme,but not the core enzyme?

It has been recently determined that the gene for Duchenne muscular dystrophy DMD is more than 2000 kb kilobases in length; however,the mRNA produced by this gene is only about 14 kb long.What is a likely cause of this discrepancy?

What are four ways that mRNA can be modified?

Describe a difference between the RNA polymerases of eukaryotes and prokaryotes.

Describe the direction of information flow in living systems.Use appropriate,scientific terms in your description.

A mutation of what type of sequence is predicted to have the greatest effect on the rate of transcription?

The relationship among a gene,a messenger RNA,and a protein is that_________ .

Due to the wobble hypothesis,which position in the codon,if changed to a different nucleotide,would be least likely to cause a change in the amino acid encoded?

In eukaryotes,which three factors appear to encourage the specific association of RNA polymerases to a specific region of DNA?

Sidney Brenner argued that the code was nonoverlapping because he considered that coding restrictions would occur if it were overlapping.A second major argument against an overlapping code involved the effect of a single nucleotide change.In an overlapping code,how many adjacent amino acids would be affected by a single nucleotide change? In a nonoverlapping code,how many amino acids would be affected?

Which transcription factor binds directly to the TATA- box sequence?

A particular mRNA makes a protein that has a unformylated methionine as its first amino acid.Did this mRNA come from a bacterial or a eukaryotic cell? Explain.

What is the initiator triplet in both bacteria and eukaryotes? What amino acid is recruited by this triplet?

Eukaryotic transcription is different than bacterial transcription because eukaryotic transcription_________ .

Which mRNA modification is likely absent if the mRNA is degrading prematurely from the 5' end of the mRNA?

When scientists were attempting to determine the structure of the genetic code,Crick and coworkers found that when three base additions or three base deletions occurred in a single gene,the wild- type phenotype was sometimes restored.These data supported the hypothesis that_________ .