Exam 22: Protein Synthesis, Posttranslational Modification, and Transport

An experimental prep is able to separate the following membrane fractions: nuclear membrane, Golgi apparatus membrane, transport vesicle membrane, and mitochondrial membrane. The membrane fractions can then be analyzed via Western blotting for the presence of specific proteins. Which fraction would indicate the presence of t-SNAREs?

Compare the chemical structures of puromycin with an aminoacylated tRNA. How do their similarities allow puromycin to function as an antibiotic?

Describe the function of the SRP receptor.

Which antibiotic functions by inhibiting cell wall synthesis?

Below are examples of sequences from seven different E. coli genes. The underlined sequences are known as sequences and the bolded AUG sequences are known as the codon.

How many GTP are hydrolyzed during a single round of translation elongation in a eukaryote?

Noncanonical base pairings of A and I would contain hydrogen bonds. The base pairing of C and I would contain hydrogen bonds.

How many potential codons does the following mRNA sequence contain?

Contrast the discrimination at the active site and at the editing site of aminoacyl-tRNA synthetases, so that combined they ensure that tRNAs are charged with the correct amino acid.

Which sequence is MOST likely to contain an O-linked oligosaccharide in the ER? (The … represents additional amino acids N-terminal or C-terminal to those shown.)

Choose the sequence that is MOST likely to be modified with the fatty acid palmitoylate in the ER. (The … represents additional amino acids N-terminal or C-terminal to those shown.)

A common feature of translation in both eukaryotes and prokaryotes is

Although the genetic code is considered universal, this may not be fully true when comparing the human nuclear code with the human mitochondrial code. Describe how and provide a specific example.

Ribosomal rRNA interacts with all EXCEPT during the process of translation.

Release factor hydrolyzes GTP during the __________ step of translation.

Aminoacyl-tRNA synthetases carry out editing

Nirenberg and Leder completed the experiment illustrated below. If the tRNA used had an anticodon that recognizes UAA and the mRNA added contained repeats of UAA, what would be the expected result? Would the membrane contain any radioactivity, and if so, which amino acid would be retained on the membrane?

How was the selectivity of the nitrocellulose filter essential in the Nirenberg-Leder experiment, which was able to assign triplet codons to specific amino acids?

How does the wobble hypothesis allow for fewer than 63 tRNAs to effectively recognize 63 codons?

Which sequence is MOST likely to be modified with the fatty acid myristoylate in the ER? (The … represents additional amino acids N-terminal to those shown.)