Biology And Biomedical Sciences BIOL 2960 Study Guide - Midterm Guide: Formaldehyde, Guanine, Epitope

Fill in the blank. Elongation during translation does NOT involve ____________.

Question 16 options:

For a given gene, what establishes the reading frame for translation?

Question 17 options:

Which of the following is the LEAST likely direct consequence of a substitution mutation?

Question 18 options:

Suppose that the pre-mRNA transcript from a eukaryotic gene is 30,000 nucleotides long, and the gene codes for a sequence of 300 amino acids. What is the best explanation for the relationship between these numbers?

Question 19 options:

Suppose an individual is born into a population with a novel mutation. Is the new mutation an evolutionary change, and why?

Question 20 options:

Part B

Think about the DNA coding sequence of a gene. If an A were swapped for a T, what kind of mutation could it cause and why?

Its one problem with 7 questions

A) Most eukaryotic cells transcribe a relatively high portion of their genome, but most of those RNA transcripts are likely not encoding for proteins. Elucidating the function(s) of that "junk" RNA is one of the next big challenges in molecular cell biology. You isolate one of those transcripts and determine that its sequence consists of 50% C, 30% U, and 20% A. What is the percentage of Gs in this transcript? (don't write the unit)

B) Which stop codon(s) can be encoded by the RNA in the previous question ("How many times do we need to tell you to stop? 1").
List the codon(s) alphabetically. If you need to enter fewer codons than the alloted number of "blanks", enter N/A .

C) From what you can tell, the sequence of the transcript you isolated in the previous question* appears quite random. Assuming that it is random, you can expect to see the various combinations of any three nucleotides at a probability that depends of the frequency of each of the nucleotides. For example, you naturally should expect to see the triplet CCC more times than AAA. What is the expected percentage of triplets corresponding to stop codon(s) in this transcript (round to one decimal place and enter just the number without "%")? *(How many times do we need to tell you to stop? 1)

D) If the length of the transcript in the previous two questions is 2,500 nucleotides, how many stop codons do you expect to find in it, based on the frequency you calculated above?

E) On average, how many bases separate each of the occurrence of the stop codon(s) (round to the nearest integer).

F) The sequence between two potential stop codons is an "open reading frame" (ORF*). Upon closer examination of the RNA sequence from the previous questions** you determine the presence of an ORF that may encode for a putative protein which is 600 amino acid residues-long. How long is the ORF?

*Open reading frame: a stretch of DNA or RNA which is uninterrupted by a stop codon and may therefore encode for a protein.

**Questions "How many times do we need to tell you to stop" 1 through 5.

G) What may be the ramifications of your analyses of the RNA you isolated*? It is clearly containing an ORF which is longer than what you expected to find based on the sequence analysis you have conducted. What would be a logical conclusions based on the comparison of the lengths of the actual and predicted ORFs? Questions "How many times do we need to tell you to stop" 1 through 6. Pick 1, 2 or 3 below