BIOD 171 Essential Microbiology Portage Learning All Module1-6( VERSION 3) Exams NEW 2023, Exams of Microbiology

Download BIOD 171 Essential Microbiology Portage Learning All Module1-6( VERSION 3) Exams NEW 2023 and more Exams Microbiology in PDF only on Docsity! BIOD 171 Essential Microbiology Portage Learning All Module1-6( VERSION 3) Exams Questions and Answers NEW 2023 Exam 1. True or False: A virus is considered a microorganism. False. Viruses are not living and as such are not considered microorganisms. Viruses can, however, be classified as microbes, a more general term that includes microorganisms and viruses. 2. What is the smallest biological unit of life? A cell. 3. At a generalized level, all cells are comprised of what? Macromolecules* *A student may also answer: Proteins, Lipids, Nucleic acids and Polysaccharides but they must answer with all four to be fully correct. How many different types of amino acids are available from which to make proteins? 20 2. Define an essential amino acid. An essential amino acid cannot be produced by the human body and as such must be take in from the environment through alternative sources (i.e) food. Exam Page 3 1. What are the two major types of nucleic acids and their roles? DNA (deoxyribonucleic acid): Contains the genetic material as well as heredity characteristics found in living organisms. RNA (ribonucleic acid): its role is for decoding the sequence of heredity information found in DNA Answer Key 1. What are the two major types of nucleic acids and their roles? There are two major types of nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleic acids are chemical molecules that carry genetic information within the cell. DNA contains a vast amount of hereditary information and is responsible for the inheritable characteristics of living organisms. RNA is responsible for deciphering the hereditary information in DNA and using it to synthesize proteins. Exam Page 4 Answer Key 1. Complete the following RNA strand and indicate how many bonds are formed for each complementary pair: 3’ GGUCAUCG 5’ 5’ CC AGC 3’ 3’ GGUCAUCG 5’ 5’ CCAGUAGC 3’ There are 2 bonds formed between A and U, and 3 bonds between G and C. Exam Page 5 Answer Key 1. The plasma membrane (select all that are true): A. Only restricts movement of materials into the cell B. Is often a bilayer comprised of lipids C. Cannot prevent essential nutrients from escaping D. Contains hydrophobic tails pointing inward B and D 2. Carbon, Hydrogen and Oxygen atoms come together to form what primary macromolecule? Give an example. Polysaccharides. Glucose, sucrose and cellulose are all acceptable answers. Exam Page 10 Answer Key 1. Identify the following cellular components by matching the number with the description. 1, Nuclear envelope Nuclear pore Ribosomes Smooth endoplasmic reticulum Se Vesicle 2 A. Cell wall B. Lysosome C. Centriole D. Rough endoplasmic reticulum E. Plasma membrane F. Nucleus G. Golgi apparatus OF 2B 3 E 4 G 5 D EXAM MODULE 2 True or False: As movement requires energy, metabolism can be defined as a controlled set of biochemical reactions that occur in only motile organisms in order to maintain life. False. Metabolism occurs in all living organisms, not just those that move. 2. True or False: Enzymes slow down chemical reactions to conserve energy. False. Enzyme catalyze (speed up) chemical reactions. 3. What is a cofactor? And give a general example. A cofactor is a small chemical component that assists an enzyme during the catalysis reactions. A cofactor is usually metal ions. Answer Key 1. Define anabolism. Anabolism is the process of building up or biosynthesis of macromolecules from small molecular units into much larger complexes. 2. In order to convert proteins into amino acids which metabolic process would be active? Catabolism would be active as proteins are made up of amino acids. Therefore the process described (proteins into amino acids) is the breakdown, or catabolism of protein. Exam Page 3 Answer Key 1. Describe the energy transfer process relative to both ATP and ADP. 2. For the catabolism of proteins and lipids, which of the following enzymes are used? Select all that apply. A. Ligases B. Proteases C. TransferasesD. Lipases B and D. Proteases breakdown proteins while lipases breakdown lipids. 3. True or False. The β-oxidation pathway catabolizes the fatty acid chains of lipids. True Exam Page 7 Answer Key 1. True or False. Plants, algae and bacteria all contain chloroplasts. False. Chloroplasts are specific to algae and plants only. 2. The process of carbon fixation begins with which of the following reactants: select all that apply. A. ATP B. Glyceraldehyde-3-phosphate C. CO2 D. NADPH E. H2O A, C, D, and E. Carbon fixation uses the ATP/NADPH produced during light reactions to convert CO2 and H2O into useful sources of energy (carbohydrates). Exam Page 8 Answer Key 1. What is one of the main functions of light reactions? Similar to the electron transport chain, one of its main functions is to generate a proton concentration gradient to generate ATP. 2. True or False: Dark reactions can occur in the presence or absence of light. True. The term ‘dark reactions’ (also known as the Calvin Cycle) simply denotes the second stage in photosynthesis—dark reactions do not actually require darkness in order to occur. Exam Page 9 Answer Key 1. How many turns (or repititions) of the Calvin Cycle are required to generate one molecule of glucose? Six. 2. Complete the following equation by placing the appropriate numbers where indicated. __CO2 + __ATP + __NADPH + __H20 → __C6H12O6 + __ADP + __NADP+ 6 CO2 + 18 ATP + 12 NADPH + 12 H20 → C6H12O6 + 18 ADP + 12 NADP+ Exam Page 10 Answer Key 1. Match the following reactions to its corresponding enzyme: 1. A + B → A-B 2. A-B → A + B 3. A- + B →A + B4. Ab + C → A + Cb A- Lyases B- Transferases C- Oxioreductaces D- Hydrolases E- Ligases F- Isomerases 1E 1. A + B → A-B Ligases 2A 2. A-B → A + B Lyases 3C 3. A— + B → A + B— Oxioreductaces 4B 4. Ab + C → A + Cb Transferases EXAM MODULE 3 . A micrometer is defined as A. 10-3 B. 10-6 C.10-9 D. 10-12 B. A micrometer is one-millionth of a meter. 2. True or False: A nanometer is longer than a micrometer. False. A nanometer is 1,000 times smaller than a micrometer. Exam Page 2 Answer Key 1. Resolution and contrast are two critical factors that influence your ability to see an object. Explain each. Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means two (or more) objects may appear as one. Contrast is the difference in light absorbance between two objects. Poor contrast gives a high background and makes the visualization of multiple objects difficult. For instance, trying to identify 2 dark colored objects at night (low light = low contrast) versus the same 2 objects in the middle of a sunny afternoon (bright light against 2 dark objects = high contrast). Exam Page 3 Answer Key 1. Assuming a constant (non-adjustable) light source power, identify the part of the microscope you would adjust to limit the amount of light entering the microscope. Select all that apply. A. Objective B. Condenser C. Iris diaphragm D. Eye piece 4G 5A 6H Exam Page 6 Answer Key 1. For each of the following questions select from the list below the single best answer: Phase-Contrast Dark Field Fluorescence Confocal This type of microscope is best suited for visualizing GFP, RFP and YFP proteins. Fluorescence 2. This type of microscope can provide detailed images of live cells without staining. Phase-Contrast 3. This type of microscope is used to greatly increase the contrast between samples and backgroundby reflecting light off of the specimen. Dark Field 4. This type of microscope is capable of capturing images in multiple focal planes, rendering a specimen in 3D Confocal Exam Page 7 Answer Key Exam Page 8 Answer Key 1. Gram-Positive cells appear _______ in color due to a ______ peptidoglycan layer in the cell wall. Purple; Thick 2. Gram-Negative cells appear _______ in color due to a ______ peptidoglycan layer in the cell wall. Pink; Thin Exam Page 9 Answer Key 1. True or False: The distinguishing characteristic of Gram-Negative bacteria is the presence of LPS in the outer membrane. True. 2. True or False: If you wish to study the motility of an organism you cannot heat fix, but you can chemically fix the specimen. False. Both heat and chemical fixation strategies will kill the cell, making motility observations impossible. Exam Page 10 Answer Key 1. You want to observe the size and shape of a cell. What is the easiest staining technique that you could perform? Name at least one dye you would use during this process. Simple stain. You could use any of the following: methylene blue, crystal violet, safranin or fuschin. 2. You suspect a patient may have TB. Once a sample has been obtained it is sent off to the lab for an acid- fast stain. If the patient were infected with TB, describe what you would expect to see on the stained slide. You would expect to see red cells (TB+) on a blue background (TB negative). 3. True or False: If a patient is suspected of having malaria, a Giemsa stain would be an appropriate differential test to perform. True. Giemsa stains are often used in the clinical setting to aid in the diagnosis of blood parasites. EXAM MODULE 4 True or False: Growth media is best suited for distinguishing between two similar species of bacteria. False. Growth media is designed to simply support (and not restrict) microbial growth. non-pathogenic E. coli can ferment both soribitol and lactose. Therefore, colonies that ferment (acidic conditions; non-pathogenic) can be differentiated from non-fermenters (neutral to basic conditions; pathogenic). Exam Page 6 Answer Key 1. What is the Gram status (Positive or Negative) of microbes growing on Eosin Methylene Blue (EMB) agar plates? Gram-Negative. EMB plates specifically restrict the growth of Gram-Positive bacteria. 2. Mannitol salt agar will turn what color in the presence of the pathogenic strain Staphylococcus aureus? Yellow. Pathogenic Staph aureus will turn the agar from red to yellow. Exam Page 7 Answer Key 1. What is the process of spreading a bacterial culture onto a petri dish? Plating. 2. In order to visual individual colonies of bacteria would you culture your sample in a liquid media oron a solid (agar) media? Why? Solid (agar) media. The primary advantage is that cells are held into place. When grown in a nutrient broth, bacterial cells can multiply but are free to move around in solution. When grown on agar within a petri dish the fixed in such as way as to form colonies. 3. True or False? The visualization of colonies on a petri dish represents bacterial cells that have often multiplied a million times over. True. To form a bacterial colony the initial cell must have multiplied many times over, often greater than a million, in order for the naked eye to resolve it. Exam Page 8 Answer Key 1. True or False. The purpose of a quadrant streak is to expand a bacterial population. False. The purpose of the quadrant streak is to generate individual colonies such that a single (pure) bacterial sample can be isolated. 2. To be considered a ‘pure’ culture, the sample (1) can be traced back to a single cell and (2)__________ ? The culture must also be free from external contaminants. Simply put, a pure sample would never contain multiple bacterial species (ie) Strep and Staph. 3. When performing a quadrant streak, the sample is spread across the plate in such as way as to form what? A dilution gradient is formed. The resulting gradient should always contain within it the growth of individual colonies. 4. In what phase of a dilution streak would you expect to find the lowest concentration of bacteria, P2 or P4? P4 (Phase 4) would contain the lowest concentration of bacteria. The phases rank (from highest to lowest), P1 > P2 > P3 > P4. Exam Page 9 Answer Key 1. True or False. When performing a dilution streak a new (or sterilized) loop must be used for each phase. True. Failure to do so would prevent the establishment of a dilution gradient, as the same bacterial concentration would be spread across both phase regions. 2. In order to encourage growth of a slow growing microbe what might a researcher do during a phase dilution streak? A researcher may either (1) opt to perform only a 3-phase dilution streak or (2) pass the loop through the previous phase multiple times (as opposed to only once). 3. True or False. To restrict the growth of a pathogenic microbe a researcher might decrease an incubator from 37°C to 25°C. True. Pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37°C, so researchers may set incubators at 25°C to restrict its growth. Exam Page 10 Answer Key 1. When given an unknown bacterial sample the first step is to expand the current bacterial population. Which form of media best suites this need? Why? A. MSA agar B. LB media C. MacConkey agar D. Columbia CNA agar B. LB media. All other options (A, C and D) are all forms of selective media, meaning they may potentially inhibit the growth of the unknown sample. The culture should be first expanded and then place onto selective/differential agar plates. EXAM MODULE 5 . Define the concept of universal precautions. Universal precautions means any and all samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials. 2. List at least 3 observations a researcher would be sure to note while assessing an unknown microbial sample. A lab researcher would be certain to note: 1. Size and shape 2. Any observable motility 3. Gram status (positive or negative) 4. The presence of any chemical reactions 5. Changes in color localized to the organism or the surrounding media 6. Capture (or draw) images of any of the characteristics described above A 4. Conjunctivitis C. Infection occurs at time of birth B D. Pus-filled lesions on skin or hair 5. Ophthalmia Neonatorum C E. Ruptured pustules; treated with Penicillin 2. True or False. The causative agent of conjunctivitis can be either bacterial or viral. True. There are bacterial (staph) and viral forms of conjunctivitis, both resulting in the inflammation of the conjunctiva and ‘pink eye.’ Exam Page 6 Answer Key 1. True or False. Tuberculosis is best identified by a Gram stain. False. Mycobacterium show poor Gram staining and show be screened via an acid-fast stain. 2. True or False. You can become infected with TB simply by sharing a drink with someone who is currently infected with TB. False. As per the Center for Disease Control (CDC) guidelines, simply shaking someone's hand, sharing a drink or even kissing cannot spread TB. 3. Identify the disease based on the following (select all that apply): It is a small, acid-fast rod usually remaining asymptomatic for up to 20 years. It affects the skin, nerves, upper respiratory tract and eyes of infected individuals. A. Tuberculosis B. Leprosy C. Scalded-skin syndrome D. Hansen’s disease E. Bacterial conjunctivitis B and D. Hansen’s disease is simply another name for Leprosy. Leprosy is characterized by its ability to remain dormant for up to 20 years as well as the effects observed relative to the patients skin, nerves, lungs and eyes. Exam Page 7 Answer Key 1. Only directly ingesting the pre-formed Clostridium toxin (neither the bacteria nor its spores) will cause disease in adults. True. The mature (adult) microbiota is capable of killing the bacteria/spores. 2. While visiting his grandparents, a 10-year-old child has green beans for dinner that were harvested from his grandparents’ garden and canned the previous year. Severe illness sets in and the child is taken to the hospital. Botulism is suspected, but what form? Explain your answer. Foodborne botulism. The child is too old (> 6 months) to be considered for infant botulism and wounds were not present. The green beans were likely improperly canned and under the low-acidic, anaerobic conditions, bacterial growth was encouraged. Exam Page 8 Answer Key 1. True or False. Although there is no cure for tetanus, it can be prevented through vaccination. True. There is no cure for tetanus. However, tetanus is entirely preventable through vaccination. 2. Describe the symptoms and treatment regimen for someone infected with Clostridium perfringens. Clostridium perfringens (also known as Gas gangrene) presents with muscle necrosis, swelling of infected areas, fever and intense gas production. Treatment entails removal of all infected tissue, often resulting in amputation of the affected areas, in conjunction with heavy antibiotic therapies. 3. Why does the alpha toxin (perfringolysin) produced during an infection of gas gangrene cause celldeath? The toxin perforates the membrane. It forms pores in the plasma membrane of host cells resulting in uncontrolled ion fluxes and eventually cell lysis and death. Exam Page 9 Answer Key 1. You develop a fever, chills and pneumonia after recently using a warm midst vaporizer in an attempt to open your sinuses. What bacterial disease would a doctor suspect is causing your symptoms? Would the doctor suspect you contracted it from touching (potentially) contaminated doorknobs? Legionnaires. No—legionella cannot be spread simply by direct contact between people. Legionella can only be transmitted through droplets small enough to be breathed in. 2. True or False. Bubonic plague is often characterized by painfully swollen lymph nodes. True. 3. Which form of the plague is highly virulent? What does it target? Pneumonic plague is highly virulent and targets the respiratory (lungs) system. Exam Page 10 Answer Key 1. Identify the following disease: Replication: The viral genome makes copies of itself Exit: Old virus leaves the cell & new viruses are produced New infection: New viruses produced leaves the host cell & go infect new cells. This process restarts Answer Key 1. True or False: Viral replication occurs after it attaches and enters the host cell. True. The viral genome is never replicated before attachment and entry. True. The viral genome is never replicated before attachment and entry. 2. Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step. Uncoating: Release: Replication: Attachment: Entry: New infection: 3- Uncoating: the viral capsid disassembles 5-Release: New virus particles are produced and leave the cell 4-Replication: the viral genome is the ‘blueprint’ to make copies of itself 1-Attachment: viral receptors bind to host proteins on the surface of the cell 2-Entry: the virus fuses with the host membrane and enters the cell 6-New infection: newly produced viruses that left the host cell now go on to infect new cells. Exam Page 4 Answer Key 1. A virus that infects bacteria is called a ____________ and contains a _____-side polygon capsid. Bacteriophage; 20-sided 2. True or False. Structurally, bacteriophages are similar to viruses that infect animals. False. Bacteriophages have a distinct composition and structure. 3. Identify the following components of a bacteriophage. Exam Page 5 Answer Key 1. Describe the main differences between lytic and temperate phages. Lytic bacteriophages replicate within the host bacteria until it ruptures, whereas temporate (or lysogenic) phages primarily exist in a non-replicative state that does not kill the host cell. Lytic phages replicate all viral proteins needed for the assembly of new virus particles whereas lysogenic phage genomes are integrated into the host genome but production of viral proteins is suppressed. 2. Based on the following image, would you expect the viral titer to be high or low? Why? Exam Page 6 Answer Key 1. Which of the following cannot be spread via airborne particles: A. Measles B. Mumps C. Rubella D. A and B E. None of the above E. Measles, mumps and rubella can all be spread via airborne particles formed while coughing, sneezing, etc. 2. True or False. A patient infected with Rubella is considered infectious one week before and after the appearance of the trademark rash. True 3. Which of the following diseases does a linear, double-stranded DNA virus cause?A. Measles B. Mumps C. Rubella D. B and C E. None of the above E. Measles, mumps and rubella are all linear, single-stranded RNA viruses 4. What disease displays as a secondary characteristic swelling of the testes/ovaries and pancreas? Mumps. A patient infected with mumps (aka epidemic parotitis) has primary swelling in the parotid (salivary glands) located in the neck but also may have secondary swelling in the testes/ovaries and pancreas.