Unit IIB Exam (v. 1.0)

Transcription

1 Unit IIB Exam (v. 1.0) 1. The lac operon. (PT1-5) a. Is found only in eukaryotic cells b. Codes for the sequence of amino acids in lactase c. Regulates the transcription of mrna d. Regulates transcription by turning on or off the production of a repressor protein e. Regulates the DNA replication by turning on or off the production of an inducer protein 2. Both viruses and prokaryotes contain. (PT1-9) a. Nucleic acids b. Ribosomes c. A plasma membrane d. A protein coat e. A peptidoglycan wall 3. Which of the following carries the code that determines the sequence of monomers in a protein? (PT-27) a. rrna b. trna c. mrna d. the large ribosome subunit e. DNA polymerase 4. Which of the following caries the code that determines the sequence of monomers in a protein? (PT1-27) a. rrna b. trna c. mrna d. the large ribosome subunit e. DNA polymerase 5. Primers that initate DNA replication consist of. (PT1-50) a. RNA nucleotides b. DNA nucleotides c. Okazaki fragments d. DNA polymerase e. Nucleosomes 6. Which of the following correctly describes plasmids? (PT1-53) a. They are composed only of RNA b. They are composed of RNA and protein c. They are DNA segments in the chromosomes of bacteria d. They are the DNA cores of viruses e. The can be transferred between bacteria during conjugation 7. DNA replication requires all of the following EXCEPT. (PT2-3) a. Primase b. Helicase c. DNA polymerase d. Topoisomerase e. Small nuclear ribonucleoproteins (snrnps) 8. A bacteriophage is a. (PT2-5) a. Virus that attacks a bacteria b. Bacterium that attacks viruses c. Bacterium that attacks eukaryotic cells d. Parasitic bacterium e. Parasitic eukaryotic cell

2 9. A transcription of the DNA sequence CCCGGAATT would produce which of the following sequences in mrna? (PT2-14) a. CCCGGAATT b. GGGCCTTAA c. AAATTCCGG d. UUUAACCAA e. GGGCCUUAA 10. An amino acid is related to a protein in the same way as. (PT2-19) a. Glycerol is related to a saturated fat b. Glycerol is related to cholesterol c. Glucose is related to a polypeptide d. Glucose is related to sugar e. Glucose is related to starch 11. During DNA replication, enzymes break the hydrogen bonds between the nucleotide base pairs to unwind the double-helix DNA molecule. What prevents the hydrogen bonds from reforming? (PT2-25) a. Helicases b. Ribozymes c. Histones d. Single-stranded binding proteins (SSBPs) e. Small nuclear ribonucleoproteins (snrnps) 12. Adenine, a nitrogen base, is found in all of the following EXCEPT. (PT2-30) a. RNA b. DNA c. ATP d. camp e. amino acids 13. In an effort to clone a human protein, material from a human cell is introduced into bacteria. Which of the following human materials are needed for this procedure? (PT2-31) a. the protein s mrna transcript found in the cytoplasm b. the protein s mrna transcript found in the nucleus c. the rrna and trna used during translation of the protein d. the segment of DNA coding for the protein s mrna transcript e. the introns which were removed from the protein s unprocessed mrna transcript 14. Which of the following statements concerning a gene is correct? ( ) a. a gene can code for a specific protein b. a gene can exist in alternate forms called introns c. a gene undergoes crossing-over during DNA replication d. a gene that is very similar in sequence in a human and in a bacterium is probably a recent mutation e. a gene that is expressed in every offspring of every generation is recessive 15. There is some evidence that interferon may be effective against certain forms of cancer. This finding suggests that some cancers involve. ( ) a. Viruses b. Bacteria c. Uric acid deposition d. Allergic reactions e. An overproduction of white blood cells

3 The next two questions refer to the following diagram. ( ) 16. Chemical group that, together with a sugar and a nitrogen base, makes up a nucleotide B 17. A hydrogen bond E The next two questions refer to the chart below. mrna Codons Amino Acids AGA Arginine GGA Glycine AGC Serine GCA Alanine CAG Glutamine glutamine-glutamine-glutamine.serine-serine-serine Which of the following messenger RNA sequences could code for both of the two amino acid sequences? ( ) a. AGCAGCAGCAGC b. AGUAGUAGUAGU c. CAACAACAACAA d. GCUGCUGCUGCU e. GCAAGCGCAACG 19. glycine-serine-glycine ( ) Which of the following DNA strands will code for the amino acid sequence above? a. ACTCCTTCT b. TCTCCGTCG c. CCGTCGACT d. CCTCCGTCG e. CCTTCGCCT 20. Which of the following terms refer to both the movement of a ribosome along a piece of mrna and the movement of a piece of one chromosome to another chromosome? ( ) a. Transduction b. Transgenesis c. Transformation d. Translocation e. Transplantation

4 21. Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because. ( ) a. Different DNA sequences can code for the same amino acid b. Some amino acid variations cannot be detected by protein electrophoresis c. DNA sequencing is a more reliable technique than protein electrophoresis d. Proteins are more easily damaged than is DNA e. DNA is more heat-sensitive and therefore varies more 22. Certain metabolic pathways are affected by the buildup of a product which interacts with an enzyme catalyzing one of the initial steps of the pathway; this can be an example of. ( ) a. Transcriptional regulation b. Thermodynamic regulation c. Translational regulation d. Feedback inhibition e. Posttranslational modification Directions: Each group of questions below consists of five lettered headings followed by a list of numbered phrases or sentences. For each numbered phrase or sentence, select the one heading to which it is most closely related and fill in the corresponding oval on the answer sheet. Each heading may be used once, more than once, or not at all in each group. The next two questions refer to the following enzymes. ( ) A. DNA ligase B. DNA polymerase C. RNA polymerase D. Restriction enzyme E. Reverse transcriptase 23. Enzyme used in synthesis of mrna C 24. Enzyme used during replication to attach Okazaki fragments to each other A The next two questions refer to the following enzymes. ( ) A. Proteins B. Carbohydrates C. Nucleic acids D. Lipids E. Steroids 25. Used for insulation and buoyancy in marine Arctic animals D 26. Used to carry the genetic code C

5 The next two questions are based on the following. In the 1940s, Avery, MacCleod, and McCarty transformed nonencapsulated bacteria into encapsulated forms by growing the nonencapsulated cells in a culture containing an extract made from dead encapsulated cells. The transformed cells produced colonies of encapsulated bacteria. Three different procedures and their results are outlined below: Procedure I: Extract made from dead encapsulated cells added to culture medium. Nonencapsulated bacteria added to culture medium. Results: Both nonencapsulated and encapsulated bacteria grow Procedure II: Extract made from dead encapsulated cells treated with protein-degrading enzymes before adding extract to culture medium. Nonencapsulated bacteria added to culture medium. Results: Both nonencapsulated and encapsulated bacteria grow Procedure III: Extract made from dead encapsulated cells treated with DNAse (an enzyme that selectively destroys DNA) before adding extract to culture medium. Nonencapsulated bacteria added to culture medium. Results: Only nonencapsulated bacteria grow 27. A reasonable conclusion to draw from the results of the experiment is that. ( ) a. DNA is the genetic material b. DNA replication is semi-conservative c. DNA is a double helix d. DNA is translated into protein e. Mutation is a change in the genetic material 28. What was the purpose of treating the extract with DNAse in Procedure III? ( ) a. To remove the encapsulated bacteria from the extract b. To serve as a positive control by demonstrating that a protein in the extract is the transforming factor c. To serve as a negative control by demonstrating that transformation does no occur without DNA d. To destroy enzymes in the extract e. To destroy any capsules that might be in the extract The next two questions are based on the following. A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained. 29. The rate of migration of the DNA fragments through the agarose gel is determined by the. ( ) a. Ratio of adenine to cytosine in the fragment b. Presence of hydrogen bonds between base pairs c. Length of time the electrophoresis unit is allowed to operate d. Number of nucleotides in the fragment e. Volume of the starting sample 30. Which of the following is true of the dye used to stain the fragments? ( ) a. It increases the contrast between the agar and the DNA fragments b. It must be accounted for when calculating the molecular weight of the fragments c. Its charged areas interfere with the migration of the DNA d. It is bonded only to the sticky ends of the fragments and can directly determine the sequence of the DNA fragments e. It gives a three-dimensional view of the structure of the DNA fragments

6 Free Response Question: Answer the question in essay form on your own sheet of paper. Remember to write legibly and clear label any diagrams used.