Spring 2007 ECOL MCB 320 Print name Sign name INSTRUCTIONS Sign the top of the first page print your name on one side of every page Approximate point values for questions are in parentheses On multiple choice questions circle the letter of the best answer You can tear off the last page with the code and keep or discard it after the exam 1 3 Genomes can NOT be a single stranded DNA b double stranded DNA c RNA d protein e circular 2 3 Most mutant alleles are a b c d e dominant recessive repressive hydromorphs advantageous 3 3 A plasmid is a a b c d e stream of very hot ions liquid component of blood bacterial chromosome DNA molecule that replicates independently of the cell genome diploid bacterium 4 3 Enhancers are a b c d e sequences that control the transcription of DNA sequences that control the translation of mRNA sequences that control the folding of protein sequences that determine the structure of nucleosomes implants that make cells more attractive 1 5 3 In the context of genetics wobble means that 1 pt for d a during translation tRNAs move back and forth so the amino acids can line up b a base in the first 5 anticodon position of the tRNA can sometimes pair with more than one bases on the mRNA c a base in the second anticodon position of the tRNA can sometimes pair with more than one bases on the mRNA d a base in the third 3 anticodon position of the tRNA can sometimes pair with more than one bases on the mRNA e during transcription a base in the third codon position of an ORF can pair with either of two bases in the mRNA 6 3 What is the N terminal amino acid in the tubulin gene of yeast Methionine 7 10 The following is a DNA sequence that includes an ORF open reading frame A C T C A G T C A G G A G T C G G T A A C T A G 5 T G A G T C A G T C C T C A G C C A T T G A T C a Draw a box around the ORF 3 pts OK if include TGA stop codon b Assuming that this ORF is a gene label the 5 end of the sense strand 3 pts c Assuming that this ORF is a gene write the sequence of the corresponding portion of the polypeptide from N terminal to C terminal using the single letter symbols for the amino acids 4 pts 1 amino acid N MAED C 8 3 The polypeptide chain of chicken egg white lysozyme consists of 129 amino acids How many nucleotide pairs are in the ORF of the gene encoding this polypeptide Show your calculation 387 129 X 3 387 OK if include stop codon for 390 np 2 Spring 2007 ECOL MCB 320 Print name 9 12 The diagram below shows a eukaryotic mRNA molecule divided into four regions numbered 1 3 with three specific base sequences numbered 4 6 a Where does translation begin 4 b The ribosome first binds in region 1 c Region 6 is called the Where does it end 5 3 pts each answer polyA tail 10 6 A cloning vector is shown in the diagram below Ampr is a gene for ampicillin resistance kanr is a gene for kanamycin resistance Restriction sites for various enzymes are shown A geneticist wishes to clone a gene in this vector The gene is shown below black with some flanking DNA Restriction sites for PvuI EcoRI and BglII are marked a What restriction enzyme should she use to clone the entire gene PvuI 3 pts b To select clones containing this DNA fragment she will select bacteria that have what phenotype circle letter for one answer a b c d ampicillin sensitive kanamycin sensitive ampicillin sensitive kanamycin resistant ampicillin resistant kanamycin sensitive ampicillin resistant kanamycin resistant 3 pts 3 11 6 The throats of fire breathing dragons are lined with ceramic tile to prevent them from burning up Ceramic tile is synthesized in a pathway with three enzyme catalyzed steps Mutants defective in ceramic tile can synthesize it if they are fed intermediates in the pathway as shown in the table means ceramic tile is synthesized if the supplement is given means no synthesis Mutants 1 2 3 Supplements B A C From these data determine the order of the intermediates A B and C and which steps are blocked in each mutant Complete the pathway by filling in the blanks with A B C and show which step each mutant blocks by writing the number of the mutant above the appropriate arrow 3 1 2 3 pts correct order of genes B C A ceramic tile 3 pts correct order of precursors 12 6 The drawing represents a replicating DNA molecule from an animal seen in the electron microscope Which number s represent the origin s of replication 3 10 6 9 13 15 The mfp gene codes for MFP My Favorite Protein in which the second amino acid is tryptophan Fill in the base sequences for the part of each of the following molecules that corresponds to tryptophan mfp gene 5 T G G 3 pts each 3 A C C mRNA 5 U G G tRNA anticodon loop for Trp 5 C C A Trp tRNA gene 5 T G G or 5 C C A preferred answer 4 Spring 2007 ECOL MCB 320 Print name 14 9 Gene R shaded box has two alleles R1 and R2 that differ in the presence absence of an EcoRI site as shown below Suppose that a segment of DNA containing the gene is PCR amplified from individuals of genotypes R1 R1 R2 R2 and R1 R2 using a pair of primers short arrows 9 kb apart The amplification products are restricted with EcoRI and subjected to electrophoresis along with a size standard whose fragment sizes are indicated Show the positions of the bands you would expect to see on the gel after the DNA is stained 15 6 A female animal with 10 000 primary oocytes can produce 10 000 eggs 3 pts A male animal with 10 000 primary spermatocytes can produce sperm 3 pts 40 000 or 20 000 40 000 correct but 20 000 accepted due to error in lecture notes 5 16 9 Below are the genotypes of some partial diplolid E coli cells with copies of the lac operon on the cell chromosome and also on an F plasmid After each genotype circle the I if the synthesis of galactosidase can be induced by lactose U if it cannot be induced and C if galactosidase is synthesized in the presence or absence of lactose c F lacI lacO lacP lacZ lacI lacO lacP lacZ F lacI lacO lacP lacZ lacI lacO lacP lacZ F lacI lacO lacP lacZ lacI lacO lacP lacZ I U C I U C I U C 3 pts each 6 Spring 2007 ECOL MCB 320 Print name Midterm 1 …