EXAM-3 (100 points), General Genetics pcb3063-01, su99, HW Bass, 9 July 1999 Initials Section I (26 points) VOCABULARY & DEFINITIONS Section II (24 points) MULTIPLE CHOICE Section III(26 points) SHORT PROBLEMS Section IV (24 points) LONG PROBLEMS - - - - - - - - - - - - - - - - - - - - - - - - TOTAL (100 PT.) bonus (4 points) EXAM 3 GRADE CLASS AVERAGE CLASS RANGE HONOR CODE (must be signed to receive grade) "I did not give or receive help on this exam" Name (written) Student ID # Signature Date -1- pcb3063-01/su99/exam3/hwb
Section I VOCABULARY + DEFINITIONS (26 points) VOCABULARY (14 pt., 2 pt. each), fill in the blanks 1 Viral-mediated transfer of bacterial genes is called _ 2 Lederberg and Tatum discovered using multiple auxotroph experiments 3 A functional bacteriophage virus will form a when plated on a lawn of bacteria. 4 The spectrum for UV mutagenesis matches the spectrum for purified nucleic acids. 5 In DNA replication, is the enzyme that nicks and unwinds DNA to compensate for the action of helicase. 6 is the enzyme that carries out transcription. 7 is the enzyme that charges trna molecules with acids. -2- pcb3063-01/su99/exam3/hwb
8 Transformation Initials DEFINITIONS (12 pt., 3 pt. each) Give brief, less than 30 word definitions for each 9 Prototroph 10 RNA primase 11 Inosine -3- pcb3063-01/su99/exam3/hwb
Section II (24 points, 3 pt. each) MULTIPLE CHOICE 1 Which of the following is false regarding Tm? A. The Tm represents the midpoint of the narrow temperature range at which DNA denatures B. The Tm increases with G + C content C. The Tm decreases with G + C content D. The Tm decreases with the A + T content E. Tm can be determined by monitoring the change in UV absorbance at 260 nm 2 Which chemical group is at the 5' end of a single polynucleotide strand? A. Hydroxyl group B. Phosphate group C. Diester group D. Purine base E. Nitrogen group 3 If guanine makes up 24% of the nucleotides in a sample of DNA then thymine would make up what percent of the bases? A. 24% B. 30% C. 40% D. 26% E. 15% 4 Phage DNA integrated into the chromosome is called a A. Lysogen B. Prophage C. Lytic phage D. Specialized transducing phage E. Insertion sequence -4- pcb3063-01/su99/exam3/hwb
multiple choice, cont. Initials 5 Which of the following statements is true regarding generalized transduction? A. Transfer involves DNA from a particular region of the bacterial chromosome B. Phage integrates at the att site in the bacterial chromosome C. The phage may contain only bacterial DNA D. It requires direct contact between donor and recipient cells E. None of the above 6 Which of the following statements is true regarding gene expression? A. The 5' end of mrna corresponds to the carboxyl terminus of the protein B. The first step is the association of mrna with ribosomes C. Involves proof-reading of the mrna D. Prokaryotic RNA usually undergoes nuclear processing E. Polypeptides are synthesized by addition of amino acids to the carboxy terminus 7 Which of the following features is common to both DNA replication and transcription? A. Nucleotides are added to the 5' end of the newly synthesized strand B. A sugar-phosphate bond is formed between the 3' hydroxyl and the 5' phosphate C. Deoxyribonucleotides are incorporated into the growing sequence D. Both RNA and DNA polymerase require oligonucleotide priming E. Both RNA and DNA polymerase initiate at promoter sequences 8 The purine bases are A. Thymine and cytosine B. Thymine and guanine C. Adenine and guanine D. Cytosine and Adenine E. Cytosine and guanine -5- pcb3063-01/su99/exam3/hwb
Section III(26 points) SHORT PROBLEMS 1 (6 points) If a single bacteriophage infects one E. coli cell present on a lawn of bacteria, and upon lysis yields 140 viable viruses, how many phages will exist in the plaque if only three more lytic cycles occur? (assume an excess of E. coli cells, and assume single infection (1 phage per host)). 2 (7 points) Why were 32 P and 35 S chosen for use in the Hershey-Chase experiment? Explain the rationale and conclusions from this experiment. 3 (5 points) Given following mrna sequence, predict the amino acid sequence produced (use the codon usage table attached to end of exam). Label the start and stop codons mrna 5'- 7m GAACAGUUAUGCCCCGACACACCUAACGGCGAAUAAAAAAAAAA-3' 4 (8 points) Define and differentiate between transcription and translation. Where do these processes fit into the central dogma of molecular genetics? -6- pcb3063-01/su99/exam3/hwb
Section IV (24 points) LONG PROBLEMS 1 (12 points) Draw and label a replication fork including the position and names of proteins, the polarity of DNA strands, and the direction (use arrows) of movement for proteins that would have a directional movement. 2 (12 points) Draw and label the steps of transcription of a eukaryotic gene with 2 introns. Be sure to label the following steps and structures (the DNA gene, the primary transcript, the cap and tail, the splicing, and a final drawing of the mature mrna as it would appear after export to the cytoplasm. Bonus - 4 pt. Define the terms penetrance and expressivitiy (2 points each). -7- pcb3063-01/su99/exam3/hwb