Genetic Mutations

Instructions
The multi-part assignment is intended to test your understanding of important concepts and to sharpen your intellectual skills of analysis, synthesis, evaluation, and application.
The intent of this assignment is to fully describe, explain, and analyze the information you learned from the textbook and other sources IN YOUR OWN WORDS. Plagiarism and/or the use of generative AI will result in a zero for the assignment.
This assignment consists of five questions. Copy these questions into a Word Document and compose your responses. Each response is worth 18 points and should be at least two paragraphs long, or more, depending upon the depth of the response. Please be sure to
reread your work prior to submission. Grammar and mechanics, including appropriate spelling, is worth 10 points.

1. Polycistronic mRNA are common in bacteria but seldom occur in eukaryotes. Describe the key differences in mRNA structure and subsequent translation that support this observation.
2. Using the RNA sequence below, determine the amino acid sequence that is
   encoded in each of the three reading frames (use the genetic code table Ch 23.2). If I told you that this RNA was pulled from the middle of an mRNA molecule that
   encoded a large polypeptide, how could you determine which reading frame is correct? Explain your reasoning.
3. 5′-AGUCUAGGCACUGA-3′
4. One tremendous feature of the genetic code is that amino acids with similar properties are often encoded for by codons that are also similar. For example,
   codons with C or U as the second nucleotide tend to encode hydrophobic amino acids. Can you hypothesize an explanation for this phenomenon in terms of the evolution of early protein synthesis machinery?
5. Below is a double-stranded bacterial (E. coli) DNA sequence coding for a hypothetical protein. Both strands are shown; the top strand reads 5’ to 3’ left to right, while the bottom strand reads 5’ to 3’ right to left. The nucleotides are
   numbered 1 to 100. NOTE: For this problem, transcription begins with and includes the red and underlined C/G (top strand/bottom strand) base pair, and RNA
   polymerase proceeds from left to right along the DNA.

o Where would the promoter be relative to the start of transcription?
o What are the first 25 nucleotides of the resulting mRNA? Indicate the 5′ and 3′ ends of the mRNA.
o What are the first 8 amino acids translated from the resulting mRNA? Indicate the amino and carboxy termini of the protein.
o Do the underlined nucleotides TAA (indicated in blue) encode a stop codon for the protein? Briefly explain your answer.

5. Answer the following questions using the same gene sequence from question 4. Please consider each scenario independently.
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o A mutation occurs, inserting an extra G/C (top strand/bottom strand) base- pair immediately after base pair 11 (shown in bold). How will this insertion mutation affect the mRNA transcript and resulting protein?
o A different mutation results in a substitution of the T/A base pair at position 30 (shown in bold and underlined) with a G/C base pair. How would this mutation affect the sequence of the protein that is produced?
o A third mutation occurs, substituting the C/G base pair at position 42 (shown in bold italics) to a T/A base pair. How would this mutation affect the
sequence of the protein that is produced?