Exam 13: The Genetic Code and Transcription

Reading the RNA sequences in a 5' to 3' direction,a base at the first position of an anticodon on the tRNA would pair with a base at the_________ position of the mRNA.

What is meant by the term heterogeneous nuclear RNA hnRNA ?

A particular mRNA is 300 nucleotides long.If a mutation in the middle of the sequence changed a codon from a AAA to a UAA then what would be a reasonable prediction?

The finding that some phage genes have multiple initiation sites is evidence against what characteristic of the genetic code?

In which cellular organelle do the three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes occur?

Explain the "wobble hypothesis" and why it allows a single tRNA to recognize more than one codon.

From the late 1950s to the mid- 1960s,numerous experiments using in vitro cell- free systems provided information on the nature of the genetic code.Briefly explain how the use of polynucleotide phosphorylase and the triplet binding assay were used to decipher the genetic code and why the triplet binding assay was more precise.

A researcher is looking at a cellular sample using an electron microscope.They observe that while mRNA is being transcribed from the DNA that ribosomes are binding to the mRNA to make proteins.Is this sample from a bacterial or a eukaryotic cell?

An mRNA that is being produced comes off of the _________.

When considering the initiation of transcription,one often finds consensus sequences located in the region of the DNA where RNA polymerases)binds.Which of the following is a common consensus sequence?

Suppose that in the use of polynucleotide phosphorylase,nucleotides A and C are added in a ratio of 1A:5C.What is the probability that an AAA sequence will occur?

What are three observations that suggested eukaryotic RNA was an intermediate between DNA and protein.

List four possible reasons that explain the importance of introns.

If there were 75 naturally occurring amino acids then what is the smallest codon size?

In a particular bacterial mutant,a specific gene is not producing a mRNA or the corresponding protein.Researchers sequence the gene and determine that there are no mutations in the coding portion of the gene.What could explain these observations?

The genetic code is fairly consistent among all organisms.The term often used to describe such consistency in the code is _________.

There is some indication that the code is in some way ordered; a certain pattern exists.Describe an observation that supports this view.

Which of the following is true regarding the genetic code?

In 1964,Nirenberg and Leder used the triplet binding assay to determine specific codon assignments.A complex of which of the following components was trapped in the nitrocellulose filter?

"Breaking the genetic code" has been referred to as one of the most significant scientific achievements in modern times.Describe in outline or brief statement form the procedures used to break the code.