Exam 9: The Molecular Biology of Translation

Starting translation at the authentic (correct) start codon is essential for translation of the correct polypeptide. Errant translation starting at the wrong codon, or even at the wrong nucleotide of the start codon, may produce an abnormal polypeptide and result in a nonfunctional protein. Compare and contrast the mechanisms used by bacteria and eukaryotes to identify the authentic start codon during translation initiation.

How might a single base INSERTION into the second codon of the coding sequence of a gene affect the amino acid sequence of a protein encoded by the gene?

Describe what is meant by a "conformational disease" and give an example. Why do you think these diseases exhibit late age of onset?

The preinitiation complex forms in bacteria when the start codon is recognized through binding of 16srRNA and what region of mRNA?

In the unlikely event that a tRNA has been charged with the wrong amino acid, which high- fidelity enzyme most likely caused the incorrect charging?

Why are eukaryotic mRNAs not polycistronic, unlike some bacterial transcripts?

If a tRNA anticodon were mutated such that it no longer performed wobble, what would be the effect on encoded proteins?

What features of proteins does two- dimensional gel electrophoresis exploit in order to separate proteins?

How does the eukaryotic ribosomal small subunit recognize the start codon on the mRNA?

What are the three phases of translation?

Compare and contrast the mechanism of action of two commonly used antibiotics. Include details about which steps of translation are inhibited, and explain how the antibiotic accomplishes this inhibition.

If the genetic code were overlapping, how many complete codons would the following sequence encode before encountering a stop codon? 5' - AUGCGAUUAAAGUGC - 3'

Given the following mRNA sequence, which of the following mRNAs would encode a protein with a different sequence of amino acids? 5' - AUG CAG UUA GCG UGC UAG - 3'

What molecule provides the energy to form charged tRNAs?

The Shine- Dalgarno sequence in bacteria_______ .