Exam 4 Fall 06 Key MCB181R Dr. Jorstad

Exam 4 Fall 06 Key MCB181R Dr. Jorstad - MCB 181R, Sec. 9...

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Instructor: Dr. S. Jorstad Exam IV For multiple choice questions (each worth 3 points), bubble all correct answers (there may be more than one); there is a 1 point penalty for incorrect answer choices. For short essays (each worth 5 points): confine your answers to the space provided on the scansheet. Writing outside those margins will adversely affect the machine-scoring of your exam; you may use bulleted points to express yourself, as long as your meaning is clear. 1. Antibiotics work by a. Keeping viruses from invading host cells. b. Targeting aspects of prokaryotic cells that differ from those in eukaryotic cells. * c. For example, interfering with various aspects of bacterial translation. * d. Interfering with aspects of meiosis, such as formation of spindle fibers. Bacterial do not have these things e. Attacking the nuclei and mitochondria of bacterial cells. ditto 2. Which of the following accurately describe(s) different ways of chemically modifying proteins after translation ( post-translational processing)? a. Protein synthesis can be blocked by inhibiting the formation of an mRNA. This would be regulating transcription b. Proteases can phosphorylate proteins, and either activate or deactivate them. Phosphotases do this; proteases cut proteins c. Carbohydrate molecules can be added as part of addressing the protein for delivery. * d. Proteins can be chopped up into functional pieces by proteases, as is the case for the gene products of the lac operon. * e. DNA can be mutated, which would change the outcome for the protein. True, but not an example of post-translational processing 3. The many different types of mutations presented in class can vary in the severity of their effects. Which of the following is/are correct regarding this topic? a. Mutations that occur in the DNA of somatic cells can be passed on to offspring. Simply not true; only mutations in germ-line cells can be passed on b. Chromosomal mutations always have severe effects. If no genes are lost or interrupted, there will be no adverse effects c. Silent mutations have more severe effects than missense mutations. Silent mutations have no effects at all on the resulting protein d. Unless the mutation occurs near the end of the coded protein, frameshift mutations have more severe effects than other point mutations.* because frameshift mutations effect every triplet/codon/amino acid sequence that follows them. 1
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e. Missense mutations always result in an improperly-folded protein. Not if the substituted amino acid has chemical properties similar to the original amino acid 3’ TA C ACCGAGGGCCTAATT 5’ 4. Refer to the DNA template strand above. If the first C (in bold) were mutated to a G, a. This would be considered a missense mutation. * wrong amino acid is specified b. This would be considered a frameshift mutation. c.
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Exam 4 Fall 06 Key MCB181R Dr. Jorstad - MCB 181R, Sec. 9...

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