Test Bank for Microbiology; The Human Experience 1ST Edition By John W. Foster Zarrintaj Aliabadi Joan L. Slonczewski

Test Bank for Microbiology The Human Experience 1st Edition By John W. Foster Zarrintaj Aliabadi Joan L. Slonczewski. Which of the following statements accurately describes the relationship between DG and Keq? a. There is no relationship, as they are independent entities. b. When Keq is greater than 1, DG is negative. c. When Keq is greater than 1, DG is positive. d. When Keq is less than 1, DG is negative. ANS: B DIF: Moderate REF: 4.4 OBJ: 4.4a Explain how energy and entropy determine the direction of reactions. MSC: Understanding 23. In a reaction where substrates A and B combine to form products C and D (A+B yields C+D), which of the following could drive the reaction to the right toward products? a. decreasing the concentration of A c. increasing the concentration of C b. decreasing the concentration of B d. decreasing the concentration of D ANS: D DIF: Difficult REF: 4.4 OBJ: 4.4a Explain how energy and entropy determine the direction of reactions. MSC: Evaluating 24. The second law of thermodynamics states that a. energy is neither created nor destroyed. b. matter is neither created nor destroyed. c. in energy transformations, disorder tends to increase. d. in energy transformations, disorder tends to decrease. ANS: C DIF: Easy REF: 4.4 OBJ: 4.4a Explain how energy and entropy determine the direction of reactions. MSC: Understanding 25. A reaction with a positive DG and low activation energy will be a. spontaneous and slow. c. endergonic and fast. b. exergonic and fast. d. endergonic and slow. ANS: C DIF: Difficult REF: 4.4 OBJ: 4.4c Explain how enzymes catalyze reactions and how various factors influence the rate of reaction. MSC: Analyzing 26. The most typical way for a cell to increase the rate of a reaction is by a. increasing the cell’s temperature. c. decreasing the cell’s pH. b. increasing the cell’s pH. d. using an enzyme. ANS: D DIF: Easy REF: 4.4 OBJ: 4.4c Explain how enzymes catalyze reactions and how various factors influence the rate of reaction. MSC: Understanding 27. An exergonic reaction may still be slow if a. the activation energy is high. c. product concentrations are low. b. an enzyme is present. d. reactant concentrations are high. ANS: A DIF: Moderate REF: 4.4 OBJ: 4.4c Explain how enzymes catalyze reactions and how various factors influence the rate of reaction. MSC: Analyzing 28. Fill in the blanks with the pair of words below that make the following sentence correct: NADH is ________ compared to NAD+ because NADH has gained ________. a. oxidized; electrons c. reduced; electrons b. oxidized; neutrons d. reduced; neutrons ANS: C DIF: Moderate REF: 4.4 OBJ: 4.4b Describe the oxidation-reduction changes that occur during reactions. MSC: Understanding 29. Which statement accurately describes membrane phospholipids? a. They are entirely hydrophobic. b. They are entirely hydrophilic. c. They have hydrophilic phosphate head groups and hydrophobic fatty acid tails. d. They have hydrophobic phosphate head groups and hydrophilic fatty acid tails. ANS: C DIF: Easy REF: 4.5 OBJ: 4.5a Describe the structure of cellular membranes. MSC: Understanding 30. In a cell membrane, phosphate head groups a. only face the extracellular environment. b. only face the aqueous cytoplasm. c. bind each other via ionic bonds in the interior of the membrane. d. face both the extracellular environment and the cytoplasm. ANS: D DIF: Easy REF: 4.5 OBJ: 4.5a Describe the structure of cellular membranes. MSC: Remembering 31. Which of the following molecules would require a transmembrane protein in order to cross a cell membrane? a. O2 c. CO2 b. H2O d. Na+ ANS: D DIF: Moderate REF: 4.5 OBJ: 4.5b Explain the concept of selective permeability of a membrane. MSC: Applying 32. Weak acids can a. never cross cell membranes. b. cross cell membranes in their uncharged form. c. cross cell membranes in their charged form. d. only cross cell membranes with the aid of a transmembrane protein. ANS: B DIF: Easy REF: 4.5 OBJ: 4.5b Explain the concept of selective permeability of a membrane. MSC: Understanding 33. You place water containing a radioactive isotope of hydrogen on the outside of a cell. Which of the following will increase the rate at which radioactive water appears on the inside of the cell? a. a decrease in temperature b. an increase in unsaturated fatty acids c. an increase in the fatty acid tail length d. a decrease in membrane surface area ANS: B DIF: Difficult REF: 4.5 OBJ: 4.5c Explain how membranes compartmentalize cells and control the movement of a cell’s molecules. MSC: Evaluating 34. There is no net movement of water into or out of cells when the cells are in which type of environment? a. isotonic c. hyperosmotic b. hypertonic d. hypotonic ANS: A DIF: Easy REF: 4.5 OBJ: 4.5d Describe the effect of osmosis on cells. MSC: Remembering 35. The bacterial cell wall offers protection against what type of environment? a. isotonic c. hypotonic b. hypertonic d. endergonic ANS: C DIF: Moderate REF: 4.5 OBJ: 4.5d Describe the effect of osmosis on cells. MSC: Understanding 36. Endosomes and phagosomes are both types of a. catalysts. c. pseudopods. b. oxidizing agents. d. vesicles. ANS: D DIF: Easy REF: 4.6 OBJ: 4.6a Describe how endocytosis and phagocytosis transport material into a eukaryotic cell. MSC: Analyzing 37. Fill in the blanks with the pair of words below that make the sentence correct. ________ takes up small extracellular particles via membrane invaginations while ________ takes up larger particles. a. Endocytosis; phagocytosis c. A pseudopod; endocytosis b. Phagocytosis; endocytosis d. A pseudopod; a lysosome ANS: A DIF: Easy REF: 4.6 OBJ: 4.6a Describe how endocytosis and phagocytosis transport material into a eukaryotic cell. MSC: Remembering 38. This image shows the effects of cholera toxin on intestinal cells. Which numbered arrow indicates the step of the toxin entering a cell via endocytosis? a. 1 c. 3 b. 2 d. 4 ANS: B DIF: Easy REF: 4.6 OBJ: 4.6b Explain how pathogens take advantage of endocytosis and phagocytosis. MSC: Understanding 39. Bacteria within a phagosome may be destroyed by the fusing of the phagosome with which acidic eukaryotic organelle? a. endoplasmic reticulum c. lysosome b. pseudopod d. vesicle ANS: C DIF: Moderate REF: 4.6 OBJ: 4.6b Explain how pathogens take advantage of endocytosis and phagocytosis. MSC: Remembering 40. You fluorescently label the phospholipid head groups of a small number of phospholipids in the outer leaflet of the cell membrane to observe them over time with a microscope. At time zero, all the fluorescent label is concentrated in one spot. What will you observe at a later time point? a. The fluorescently tagged phospholipids will still be together, concentrated in a spot. b. The fluorescently tagged phospholipids will be spread out, but will still all be part of the outer leaflet. c. The fluorescently tagged phospholipids will be spread out in the outer leaflet and some will have flip-flopped into the inner leaflet as well. d. It is impossible to predict what will happen to the labeled phospholipids over time. ANS: B DIF: Difficult REF: 4.5 OBJ: 4.5a Describe the structure of cellular membranes. MSC: Applying 41. CASE HISTORY In October 2013, Kelsey was a 28-year-old computer programmer who worked for a prominent technology firm in Silicon Valley. In the middle of the night, Kelsey awoke with abdominal cramps and diarrhea. Her temperature spiked as high as 40°C (104°F). She had a bad headache and could not retain sufficient fluids. After three days, her fever subsided, but the diarrhea continued (about 20 times a day) and began showing blood. Kelsey was admitted to the hospital, where she was given intravenous fluids to control her dehydration. The physician asked her about her dietary history preceding the onset of symptoms. Kelsey recalled that the night before onset, she had eaten rotisserie chicken cooked at the supermarket. An antibody test confirmed the diagnosis of Salmonella enterica serovar heidelberg. Because of the severity of her symptoms, Kelsey was treated with antibiotics, although sometimes antibiotics may prolong the persistence of Salmonella. When amoxicillin failed to control the infection because of bacterial resistance, ciprofloxacin was used. Ultimately, Kelsey’s illness was one of more than 400 cases in 23 states traced to contaminated chicken from one California farm. Kelsey recovered, but three months later, S. heidelberg could still be detected in her feces. Kelsey’s diarrhea could be caused by which of the following: a. The Salmonella infection created an isotonic environment in the lumen of Kelsey’s gut, leading water to leave her epithelial cells. b. The Salmonella infection created a hypertonic environment in the lumen of Kelsey’s gut, leading water to leave her epithelial cells. c. The Salmonella infection created an acidic environment in the lumen of Kelsey’s gut, leading water to leave her epithelial cells. d. The Salmonella infection created an oxidizing environment in the lumen of Kelsey’s gut, leading water to leave her epithelial cells. ANS: B DIF: Easy REF: Case History 4.1 OBJ: 4.5d Describe the effect of osmosis on cells. MSC: Understanding COMPLETION 1. Shown are four different representations of methane. Letter ________ shows a space-filling model. A B C D ANS: C DIF: Easy REF: 4.1 OBJ: 4.1a Describe how atoms form the molecules of life. MSC: Remembering 2. Shown are four different representations of methane. Letter ________ shows a structural formula. A B C D ANS: B DIF: Easy REF: 4.1 OBJ: 4.1a Describe how atoms form the molecules of life. MSC: Remembering 3. Shown is the outer electron shell of nitrogen. Nitrogen will form ________ bonds with other atoms. ANS: 3 DIF: Moderate REF: 4.1 OBJ: 4.1a Describe how atoms form the molecules of life. MSC: Understanding 4. The sharing of electrons between two atoms forms ________ bonds. ANS: covalent DIF: Moderate REF: 4.1 OBJ: 4.1b Describe the types of bonds atoms can form to make a molecule. MSC: Remembering 5. ________ is the general name for a six-carbon sugar. ANS: Hexose DIF: Moderate REF: 4.2 OBJ: 4.2c Describe the structure of sugars and polysaccharides. MSC: Remembering 6. Redox reactions involve the movement of ________ from one molecule or atom to another. ANS: electrons DIF: Easy REF: 4.4 OBJ: 4.4b Describe the oxidation-reduction changes that occur during reactions. MSC: Remembering SHORT ANSWER 1. Describe the difference between ionic and hydrogen bonds. ANS: Ionic bonds are electrostatic attractions between atoms having full positive and negative charges (i.e., cations and anions). Hydrogen bonds are weaker and occur between atoms having partial positive and negative charges. DIF: Difficult REF: 4.1 OBJ: 4.1b Describe the types of bonds atoms can form to make a molecule. MSC: Analyzing 2. What is a condensation reaction? ANS: A condensation reaction occurs when water is released as a product when two monomers join together via a covalent bond. Examples include fatty acids condensing with glycerol to form triglycerides and the joining of two amino acids during peptide bond formation. DIF: Moderate REF: 4.2 OBJ: 4.2a Describe organic molecules, and explain the role of functional groups and the formation of macromolecules. MSC: Understanding 3. What are some structural differences between cellular DNA and RNA? ANS: DNA is double stranded and contains the sugar deoxyribose and the base thymine. RNA is single stranded and contains the sugar ribose and the base uracil instead of thymine. DIF: Moderate REF: 4.3 OBJ: 4.3b Describe the structure and diverse functions of RNA. MSC: Analyzing 4. What does amphipathic mean? ANS: Amphipathic refers to a molecule that has both hydrophilic and hydrophobic regions. Phospholipids are an example of amphipathic molecules. DIF: Moderate REF: 4.5 OBJ: 4.5a Describe the structure of cellular membranes. MSC: Understanding 5. What is osmosis and why is it important for cells to maintain osmotic balance? ANS: Osmosis is the diffusion of water from areas of high water concentration to areas of low water concentration. It is important for cells to maintain water balance because an influx of water can cause cells to swell (and potentially burst) while a net efflux of water can shrink cells and cause abnormally high cell-solute concentrations. DIF: Difficult REF: 4.5 OBJ: 4.5d Describe the effect of osmosis on cells. MSC: Understanding 6. The molecular formula of the amino acid glycine is C2H5NO2. What is the molecular formula of a glycine pentapeptide? ANS: C10H25N5O10 DIF: Difficult REF: 4.3 OBJ: 4.3c Describe the fundamental structure of proteins. MSC: Applying 7. CASE HISTORY Water is the most abundant molecule of life—but too much water can be deadly. In the summer of 2010, heavy rains flooded Pakistan, submerging one-fifth of the country. Millions of people were displaced and exposed to water contaminated by microbial pathogens. Diarrheal disease threatened many, especially children. A ten-year-old boy named Akal developed profuse diarrhea. He showed extreme thirst, but clean drinking water was unavailable. His diarrhea became watery and cloudy with white flecks of intestinal mucus (known as rice-water stool). Akal became listless, his eyes sunken and his skin wrinkled from dehydration. A nurse observed a sample of Akal’s diarrheal fluid under darkfield microscopy. Numerous bacteria swam rapidly, appearing like “twinkling stars.” The bacteria, comma-shaped bacilli, stained Gram negative. Later testing confirmed Vibrio cholerae, the cause of cholera. These bacteria produce cholera toxin, a protein complex that causes intestinal epithelial cells to secrete large amounts of chloride ion (Cl- ). The high chloride concentration draws out the positively charged sodium ions (Na+ ). The increased extracellular salt (Na+ and Cl- , or NaCl) causes water to diffuse out of the epithelial cells, leading to dehydration and diarrhea. Without treatment, Akal’s chance of death was 50%. Akal was treated with oral rehydration therapy (ORT), a method invented by Bangladeshi physicians. ORT involves gradual feeding of a solution containing glucose and NaCl to replace ions and water lost through the diarrhea. Within hours, Akal’s flesh had rehydrated, and within a week he made a full recovery. Explain the properties of cell membranes that lead to the loss of water from epithelial cells in response to cholera toxin. ANS: Students should discuss selective permeability of the membrane and its relationship to water and the ions mentioned in the case history. DIF: Moderate REF: Chapter 4 Introduction OBJ: 4.5b Explain the concept of selective permeability of a membrane. MSC: Applying 8. CASE HISTORY In October 2013, Kelsey was a 28-year-old computer programmer who worked for a prominent technology firm in Silicon Valley. In the middle of the night, Kelsey awoke with abdominal cramps and diarrhea. Her temperature spiked as high as 40°C (104°F). She had a bad headache and could not retain sufficient fluids. After three days, her fever subsided, but the diarrhea continued (about 20 times a day) and began showing blood. Kelsey was admitted to the hospital, where she was given intravenous fluids to control her dehydration. The physician asked her about her dietary history preceding the onset of symptoms. Kelsey recalled that the night before onset, she had eaten rotisserie chicken cooked at the supermarket. An antibody test confirmed the diagnosis of Salmonella enterica serovar heidelberg. Because of the severity of her symptoms, Kelsey was treated with antibiotics, although sometimes antibiotics may prolong the persistence of Salmonella. When amoxicillin failed to control the infection because of bacterial resistance, ciprofloxacin was used. Ultimately, Kelsey’s illness was one of more than 400 cases in 23 states traced to contaminated chicken from one California farm. Kelsey recovered, but three months later, S. heidelberg could still be detected in her feces. Kelsey’s illness is caused by a facultative intracellular bacterium, meaning when causing infection it may enter human cells. Explain the process by which large particles such as a bacterial cell can enter membrane covered cells like human intestinal epithelia. ANS: Students should discuss endocytosis. Advanced students may note that this is induced by the bacterium in the case of Salmonella. DIF: Moderate REF: Case History 4.1 OBJ: 4.6a Describe how endocytosis and phagocytosis transport material into a eukaryotic cell. MSC: Understanding Chapter 05: Cell Biology of Bacteria and Eukaryotes MULTIPLE CHOICE 1. In this scanning electron micrograph of Borrelia burgdorferi, which of the following structures is visible? a. the outer sheath c. the genome b. cytoplasmic filaments d. flagellar motors ANS: A DIF: Easy REF: 5.1 OBJ: 5.1a Describe the structure and function of the bacterial cell wall, and explain its importance as a target for antibiotics. MSC: Analyzing 2. The cell wall is part of the a. cell membrane. c. cell envelope. b. cytoplasm. d. proteome. ANS: C DIF: Moderate REF: 5.1 OBJ: 5.1a Describe the structure and function of the bacterial cell wall, and explain its importance as a target for antibiotics. MSC: Understanding 3. Lipopolysaccharides are found in a. Gram-positive bacteria. c. archaea. b. Gram-negative bacteria. d. eukaryotic microbes. ANS: B DIF: Easy REF: 5.1 OBJ: 5.1b Explain the Gram-negative envelope structure and the role of LPS in pathogenesis. MSC: Remembering 4. In Gram-negative bacteria, peptidoglycan is found in the a. cytoplasm. c. outer membrane. b. inner membrane. d. periplasm. ANS: D DIF: Moderate REF: 5.1 OBJ: 5.1b Explain the Gram-negative envelope structure and the role of LPS in pathogenesis. MSC: Understanding