I know this is vague, and you wouldn’t understand unless you were in class, but
ID: 280950 • Letter: I
Question
I know this is vague, and you wouldn’t understand unless you were in class, but you could at least answer how the question could be worded differently to make it less “tricky”Thanks, of course I rate quick!! The extra credit opportunity is based on the following question that appeared on Quiz 5 (both the Individual and Group parts). You are eligible for up to 5 points of extra credit for completing the following 3 questions (to be added to your final exam score). Your response to these questions is due at the start of class on Monday. Rewrite the question and present it in a way that you think clarifies what the question is asking. In other words, now that you know how to solve this question, how could the question itself be improved to prompt the correct answer choice? Or. what would have made it easier for you to understand what the question is asking? (In any case, to get credit for this part, you need to rewrite the question). A. Write an annotated key for the question. This can include diagrams and text (not just diagrams alone). Write the answer in a way that would be helpful for future Bio201L students to understand how to solve this question. B. C. Think about your thinking-This is a meta-cognition task. Reflect upon the discussion you had in class with your fellow students during the group quiz or, reflect upon your thinking while you completed parts A and B (above). Was there anything during these discussions, or writing, that changed or illuminated how you understand any of the following: the genetic code, t-RNAs, mRNAs, definition of a gene, coding & non-coding strands or anything else related to the topic? In other words, did any lightbulbs go off for you during the group quiz discussion or during your work on this extra-credit opportunity? Note, there is not a right answer here-you can say "nothing helped to illuminate my thinking about any of this" if that is, in fact, true!) Question to write about: A mutation in the DNA of a gene produced a UGA stop codon in the middle of the mRNA encoded by the gene. In the same cell a second mutation occurred that leads to a single nucleotide change in a tRNA that allowed the correct translation of the protein. This is an example of what is called "second site suppression". The second mutation "suppresses" the defect caused by the first mutation. The altered tRNA translates the UGA as tryptophan. What nucleotide change has likely occurred in the non-template (i.e. coding) strand of the mutant tRNA gene? (You may ignore the effects of wobble.) B. C to T A. G to A Answer: B C. A to G D. C to G
Explanation / Answer
Mutation in the tRNA gene lead to the suppression of the effect of first mutation introduced in the middle of mRNA. Thus the phenotypic effect of non sense mutation is suppressed by the second mutation in the tRNA thus the mRNA will be translated fully Now the stop codon will be read as tryptophan instead of stoping translation process the other positions/amino acids in the polypeptide chain will remain unaffected.
mRNA UGA stop codon
Template strand ACC
Non template/coding strand TGG