Skip to content
← Theoretical A

Q2 - Estimating Translation Rate from a TMV Protein Pulse-Chase Gel

Theoretical A Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Translation & the Genetic Code

Translational rate of a mRNA can be estimated from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In this experiment, a tobacco mosaic virus (TMV) mRNA, which encodes a 116,000-dalton protein, was translated in a rabbit reticulocyte lysate in the presence of 35S-methionine. The lysate contained all components of rabbit reticulocyte translational machinery. Samples were removed at 1-minute intervals and subjected to SDS-PAGE. The separated translation products were visualized by autoradiography. As can be seen in the figure below, the largest detectable polypeptides get larger with time, until the full-length protein appears at about 25 minutes.

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. The rate of TMV protein synthesis is exponentially proportional to time.
B. With an average molecular mass of an amino acid of 110 daltons, the average rate of protein synthesis is approximately 35 to 40 amino acids per minute.
C. The rabbit reticulocyte lysate contains methionyl-tRNA synthetase
D. The mRNA may contain more than two rare codons in its sequence.
← Previous: Q1 Next: Q3 →

Question reproduced from IBO 2016, Theoretical Paper A, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)