Microbiology Quiz 1

1) Which of the following statements is INCORRECT regarding prokaryotic cells? E) They lack a plasma membrane. 2) Each of the following statements concerning the gram-positive cell wall is true EXCEPT C) it protects the cell in a hypertonic environment. 3) Which of the following statements best describes what happens when a bacterial cell is placed in a solution containing 5% NaCl? C) Water will move out of the cell. 4) A gram-positive bacterium suddenly acquires resistance to the antibiotic methicillin. This trait most likely occurred due to acquisition of new genetic information through A) conjugation. 5) By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration? C) active transport 6) Which of the following is NOT a typical characteristic of most bacterial plasma membranes? D) contains cholesterol 7) Which one of the following organisms has a cell wall? B) fungi 8) Which of the following statements is TRUE? B) Endospores allow a cell to survive environmental changes by producing a dormant period with no growth. 9) Which of the following pairs is mismatched? D) centrosome — food storage 10) Which of the following organelles most closely resembles a prokaryotic cell? B) mitochondrion 11) Antibiotics that target cell wall synthesis ultimately cause bacterial cell death as a result of A) osmotic lysis. 12) Bacteria are a commonly used organism for studies of genetic material in the research laboratory. The nucleic acids must first be isolated from the cells for these studies. Which of the following would most likely be used to lyse gram-positive bacterial cells for nucleic acid isolation? A) lysozyme 13) Which of the following statements about gram-negative cell walls is FALSE? D) They are sensitive to penicillin. 1 14) Which of the following structures is NOT found in some prokaryotic cells? C) cilium 15) Functions of the glycocalyx include all of the following EXCEPT E) binary fission. 16) Which structure acts like an "invisibility cloak" and protects bacteria from being phagocytized? C) capsule 17) Which of the following is NOT part of the passive transport process? C) ATP 18) In bacteria, photosynthetic pigments are found in C) chromatophores. 19) The difference between simple diffusion and facilitated diffusion is that facilitated diffusion D) requires transporter proteins. 20. The words run and tumble are generally associated with B) taxic movements of the cell in response to attractants or repellents 21) You have isolated a motile, gram-positive cell with no visible nucleus. You can safely assume that the cell C) has a cell wall. 22) Fimbriae and pili differ in that D) pili are used for transfer of DNA and motility. 23) Where are phospholipids most likely found in a prokaryotic cell? C) the plasma membrane 25) Where are phospholipids most likely found in a eukaryotic cell? E) the plasma membrane, around organelles, and surrounding flagella 26) Which of the following is NOT found or observed to occur in both mitochondria and prokaryotes? C) cell wall 34) Which of the following statements is correct about passive diffusion? E) It involves movement of molecules down a concentration gradient and may require a transport protein. 35) Oxygen crosses a plasma membrane B) through simple diffusion. 2 36) In a hypertonic solution, a bacterial cell will typically D) plasmolyze. 38) How do spirochetes and spirilla differ? C) Spirilla have an external flagella but spirochetes have axial filaments. 53) Which of the following compounds is NOT an enzyme? C) coenzyme A 55) Which organism is NOT correctly matched to its energy source? B) photoautotroph - CO2 56) Which of the following statements about anaerobic respiration is FALSE? C) It involves the reduction of an organic final electron acceptor. 58) What is the fate of pyruvic acid in an organism that uses aerobic respiration? E) It is converted into acetyl CoA. 61) Fatty acids are oxidized in A) the Krebs cycle. 63) Which of the following is the best definition of oxidative phosphorylation? B) A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP. 64) Which of the following statements about substrate-level phosphorylation is FALSE? D) The oxidation of intermediate metabolic compounds releases energy that is used to generate 65) Which of the following statements about photophosphorylation is FALSE? D) It requires CO2. 66) A strictly fermentative bacterium produces energy A) by glycolysis only. 67) The advantage of the pentose phosphate pathway is that it produces all of the following EXCEPT C) three ATPs. 68) Which biochemical process is NOT used during glycolysis? D) beta oxidation 69) In noncyclic photophosphorylation, O2 is released from B) H2O. 70) Which of the following is the best definition of fermentation? 3 B) the partial oxidation of glucose with organic molecules serving as electron acceptors 71) Which of the following is NOT necessary for respiration? D) oxygen 72) Which one of the following would you predict is an allosteric inhibitor of the Krebs cycle enzyme, α-ketoglutarate dehydrogenase? D) NADH 73) In green and purple bacteria, electrons to reduce CO2 can come from D) H2S. 74) Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacterial lipases should cause the pH of the medium to B) decrease. 75) Which of the following uses CO2 for carbon and H2 for energy? A) chemoautotroph 76) Which of the following uses glucose for carbon and energy? B) chemoheterotroph 77) Which of the following has bacteriochlorophylls and uses alcohols for carbon? D) photoheterotroph 78) Cyanobacteria are a type of C) photoautotroph. 79) 5-ATP can be generated by the flow of protons across protein channels. A) 2, 4, 5 80) Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as C) heterolactic fermenters. 81) Which of the following statements regarding metabolism is FALSE? D) Anabolic reactions are degradative. 83) Which of the following statements regarding the Entner-Doudoroff pathway is TRUE? E) NADH and ATP are generated. 84) Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation? B) O2 is in the medium. 4 86) An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of the following EXCEPT B) competitive inhibition. 97) A urease test is used to identify Mycobacterium tuberculosis because B) M. tuberculosis produces urease. 98) Researchers are developing a ribozyme that cleaves the HIV genome. This pharmaceutical agent could be described as A) an RNA molecule capable of catalysis. 115) If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells' D) DNA and proteins. 116) Which of the following elements is NOT correctly matched with its cellular function? E) phosphorus — used for production of carbohydrates. 117) Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are B) capnophiles that grow best in carbon dioxide incubators. 163) Which of the following is the best method to sterilize heat-labile solutions? C) membrane filtration 164) Which of the following best describes the pattern of microbial death? A) The cells in a population die at a constant rate. 165) Which of the following chemical agents is used for sterilization? C) ethylene oxide 166) Which of the following substances is used for surgical hand scrubs? C) chlorhexidine 167) Which of the following pairs of terms is mismatched? A) bacteriostatic — kills vegetative bacterial cells 168) The antimicrobial activity of chlorine is due to which of the following? A) the formation of hypochlorous acid 169) Which of the following regarding antimicrobial control agents is FALSE? E) Alcohols effectively inactivate nonenveloped viruses by attacking lipids. 170) Which of the following does NOT achieve sterilization? B) pasteurization 171) Which of the following is a limitation of the autoclave? 5 D) It cannot be used with heat-labile materials. 195) An iodophor is a(n) E) iodine mixed with a surfactant. 196) Ethylene oxide D) is a sterilizing agent. 197) All of the following substances are used to preserve foods EXCEPT A) biguanides. 198) All of the following are effective for destroying prions EXCEPT A) boiling. 199) Which of the following pairs is mismatched? E) ultraviolet radiation — desiccation 6