Name: BIO 2441 – Microbiology

Module 2 Take-Home Exam

Answer the following 10 questions for 5 points each and upload the .docx file for grading. The exam is open notes, but your answers need to be your own and should not be shared with others. Please note that when you submit your exam, your answers will be scanned for plagiarism and copying.

Question 1) Describe three examples of horizontal gene transfer and explain how we can use these processes to create genetically modified organisms (GMOs).

Question 2) Predict what would happen if all the hydrogen bonds between nucleotides suddenly became permanent and unbreakable. As a follow up, compare that to what would happen if hydrogen bonds were suddenly unable to form at all. Be specific.

Question 3) Explain how methylation of the origin of replication (oriC) is involved in chromosome replication. Next, predict what would happen to chromosome replication if the cell were suddenly unable to methylate DNA. Be specific.

Question 4) Explain why RNA stability varies so greatly among the different types of RNA (mRNA vs tRNA vs rRNA, etc). Be specific.

Question 5) Using what you know about the genetic code, explain why codons are always made up of three nucleotides rather that 2 or 4. Suppose you found a new lifeform on another planet that used 4-base codons (assume they still used A, U, G and C for bases). Predict what you might learn about the variety and number of different amino acids used by that organism. Be specific.

Question 6) Explain how the discovery of bacterial defense mechanisms (restriction/modification, CRISPR) led to advances in the field of genetics research.

Question 7) Compare and contrast error-proof and error-prone DNA repair mechanisms (other than the fact that one is error-proof and the other is error-prone). Describe the conditions under which a cell would use error-prone mechanisms rather than error-proof.

Question 8) Compare and contrast gene regulation strategies used by repressor proteins and activator proteins. Relate these strategies to biosynthesis and metabolism within the cell.

Question 9) Evaluate the following statement: “bacteria find nutrients by randomly swimming around until they bump into something they can use.” Justify your answer.

Question 10) Describe the connection between quorum sensing and biofilms. Using this information, propose a strategy to prevent biofilms by interfering with the quorum sensing pathways