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BIOLOGY 204 GENERAL MICROBIOLOGY INSTRUCTOR: Dr A. Hemsley ANTELOPE VALLEY COLLEGE FALL 2005 THEORY TEST 2 100 POINTS STUDENT NAME: ___________________________________ STUDENT I.D. NUMBER: _____________________________ • • • • • • • Perusal time = 10 minutes Test time = 105 minutes ANSWER ALL QUESTIONS Read ALL questions carefully during perusal time, you may write if you wish. Use the back of each sheet if you do not have enough writing space, but please label each answer. Question subheadings are NOT of equal points value. Points allocated for each subheading are shown at the end of the question. GOOD LUCK! QUESTION 1 (Total =10 points) Match entries in the left column with answers from the lettered choices in the right colum n. Write your letter choice to the far left of each question in the spaces provided. Use each answer only ONCE. (1 Point per correct pair) _____ 1. A disinfectant that is an effective degermer a. Iodine _____ 2. Early antiseptic, now considered carcinogenic b. Autoclave _____ 3. Halogen used extensively in municipal water treatment c. Bacteriostasis _____ 4. Halogen used as an antiseptic, very effective as a tincture d. Virucide _____ 5 Enzyme denaturants, some toxicity e. Sanitization _____ 6. Prevention of bacterial growth without killing the bacteria present f. Triclocarban _____ 7. Instrument using pressurized steam to sterilize g. Ethanol _____8. h. Chlorine Agent capable of killing viruses i Heavy metals _____ 10. Surface active agent capable of assisting in mechanical j. Phenol _____ 9. (e.g. mercurochrome) Reduction of pathogen counts on eating and drinking utensils to safe public health levels degerming page 1 QUESTION 2 (Total =10 points) Flask A contains Clostridium tetani cells in glucose minimal salts medium, incubated at 37oC with aeration. Flask B contains Clostridium tetani cells in glucose minimal salts medium, incubated at 37oC in an anaerobic jar. The cultures are both grown for twenty-four hours. a. Which culture produced more ATP? b. Which culture had the shorter generation time? Why? c. Which culture had the greater cell mass? Why? d. Referring back to your answer to Part C., what are the cells in the other culture likely to be doing? page 2 QUESTION 3 (Total =20 points) A. As a hospital administrator, you have been asked to purchase the disinfectants and antiseptics for a new hospital. Briefly discuss four factors that might influence your choices of purchase. Remember, a well-organized answer will gain more points! (16) B. Provide four purposes of culturing microbes (4) Page 3 QUESTION 4 (Total =20 points) A. Describe the phenomenon of multiple replication forks as it has been observed in bacterial DNA replication (5) B. What advantage do bacteria gain from the process you described in Part A.? C. List three other strategies bacteria can use to gain the same advantage you have outlined in Part B. (5) (5) D. The enzyme DNA Ligase requires an ATP molecule to provide energy when it joins DNA fragments together, but DNA Polymerase does not require ATP. Explain why this is so. page 4 QUESTION 5 (Total =20 points) Fill in the blanks in the following sentences. (1 point per correct sentence) 1. The nucleotide that pairs with C in RNA is____________________________. 2. The first amino acid in all protein molecules is____________________________. 3. The codon sequence that signals protein synthesis initiation is 4. A microbial test commonly performed to detect carcinogens is the ____________________________. 5. One physical agent capable of causing mutations is ____________________________. 6. A DNA mutation where a base change does not affect the protein sequence of the gene product is ____________________________. called a ____________________________ mutation. 7. A DNA mutation where a base change affects one amino acid in the protein sequence of the gene product is called a ____________________________ mutation. 8. A DNA mutation where a base change introduces a STOP codon in the protein sequence of the gene product is called a ____________________________ mutation. 9. One target area of a microbe that disinfectants may injure is the____________________________. 10. ____________________________is a mechanism introduces new genetic material into a bacterium as naked DNA. 11. ____________________________ is a mechanism introduces new genetic material into a bacterium by way of a bacteriophage vector. 12. ____________________________ is a mechanism introduces new genetic material into a bacterium due to a mating event initiated by the F plasmid. 13. Plasmids confer a survival advantage, such as____________________________ to bacteria possessing them. 14. ____________________________ is an enzyme that catalyses the formation of a DNA chain. 15. The ____________________________ is an enzyme used to cut DNA at specific sequences. 16. One important recombinant gene product expressed in bacteria is____________________________. 17. A method of artificially introducing genes into cells is ____________________________ . 18. A recombinant vaccine produced in yeast cells is the ____________________________. 19. A vaccine that consists of proteins alone is known as a ____________________________. 20. One agricultural application of genetic engineering is _____________________________ (give a specific example). page 5 QUESTION 6 (Total = 20 points) You are planning to clone a gene from a frost-resistant weed into an alfalfa plant. You have located the gene for frost resistance and have 4 restriction enzymes available that would remove a piece of DNA containing this gene from one of the plant chromosomes. The restriction enzymes you could use are shown here, with small arrows indicating the sites of the nicks introduced into the sugar phosphate backbone. Pci I …ACATGT…3’ 3’ … TGTACA…5’ 5’ Bsr G I 5’ …TGTACA…3’ 3’ …ACATGT…5’ Cvi A II 5’ Nsp I 5’…RCATGY…3’ 3’ …YGTACR…5’ …CATG…3’ 3’ …GTAC…5’ R = any purine Y = any pyrimidine A. Which 2 enzymes would generate compatible ends on DNA fragments cut from the weed and a plasmid polylinker? Explain your answer (10) B. Which enzyme would generate ends that were the most difficult to rejoin? (5) C. Explain your answer to part B. (5) page 6