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BIOD171 Portage Microbiology Final Exam: Expert-
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Question 1: Which of the following is not a primary function of proteins in a cell?
- A. Facilitating the movement of materials in or out of a cell
- B. Acting as enzymes to speed up biochemical processes
- C. Providing genetic instructions for cellular reproduction
- D. Playing a structural role in the cell Correct Answer: C. Providing genetic instructions for cellular reproduction Rationale: Proteins facilitate transport, act as enzymes, and provide structural support. Genetic instructions are provided by nucleic acids (DNA and RNA), not proteins. Question 2: Which bacterial morphology describes a curved rod shape?
- A. Coccus
- B. Bacillus
- C. Vibrio
- D. Spirillum Correct Answer: C. Vibrio Rationale: Vibrio bacteria are curved rods, while coccus refers to round/spherical shapes, bacillus to rods, and spirillum to spiral or corkscrew shapes. Question 3: The main classifications of Eukarya include all of the following except :
- A. Animalia
- B. Plantae
- C. Protista
- D. Archaea Correct Answer: D. Archaea Rationale: Archaea is not part of Eukarya; it belongs to a separate domain. The main classifications of Eukarya are Animalia, Plantae, Fungi, and Protista. Question 4: Which organelle is correctly matched with its primary function?
- A. Lysosomes — Protein synthesis
- B. Mitochondria — ATP generation
- C. Golgi apparatus — Waste disposal
- D. Ribosomes — Photosynthesis Correct Answer: B. Mitochondria — ATP generation Rationale: Mitochondria are responsible for generating ATP. Ribosomes are involved in protein synthesis, the Golgi apparatus modifies and distributes proteins, and lysosomes handle waste disposal. Question 5: True or False: Enzymes are polysaccharides that catalyze chemical reactions. Correct Answer: False Rationale: Enzymes are proteins, not polysaccharides. They catalyze chemical reactions by lowering the activation energy required. Question 6: What are usually metal ions known to assist enzymes during the catalysis reaction?
- A. Coenzymes
- B. Cofactors
- C. Substrates
- D. Catalysts Correct Answer: B. Cofactors
True or False. The β-oxidation pathway catabolizes the fatty acid chains of lipids. - - CORRECT ANS- - True 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 - - CORRECT ANS- - 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). What is one of the main functions of light reactions? - - CORRECT ANS- - Similar to the electron transport chain, one of its main functions is to generate a proton concentration gradient to generate ATP. True or False: Dark reactions can occur in the presence or absence of light. - - CORRECT ANS- - True. How many turns (or repititions) of the Calvin Cycle are required to generate one molecule of glucose? - - CORRECT ANS- - 6 Complete the following equation by placing the appropriate numbers where indicated. __CO2 + __ATP + __NADPH + __H20 → __C6H12O6 + __ADP + __NADP+ - - CORRECT ANS- - 6 CO2 + 18 ATP + 12 NADPH + 12 H20 → C6H12O6 + 18 ADP + 12 NADP+ Match the following reactions to its corresponding enzyme:
- A + B → A-B
- A-B → A + B
- A- + B →A + B-
- Ab + C → A + Cb A- Lyases B- Transferases C- Oxioreductaces D- Hydrolases E- Ligases F- Isomerases - - CORRECT ANS- - 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 A micrometer is defined as - - CORRECT ANS- - 10 - 6 (one millionth of a meter) True or False: A nanometer is longer than a micrometer. - - CORRECT ANS- - False. A nanometer is 1,000 times smaller than a micrometer. Resolution and contrast are two critical factors that influence your ability to see an object. Explain each. - - CORRECT ANS- - Resolution refers to the distance between two objects at which the objects still can be seen as separate. Poor or low resolution means 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.
Name one substance capable of chemically fixing cells to a slide. - - CORRECT ANS- - Ethanol 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. - - CORRECT ANS- - Simple stain via methylene blue, crystal violet, safranin or fuschin. 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. - - CORRECT ANS- - You would expect to see red cells (TB+) on a blue background (TB negative) True or False: If a patient is suspected of having malaria, a Giemsa stain would be an appropriate differential test to perform. - - CORRECT ANS- - True. The distinctions for Lancefield subgroupings lie in its: ( - - CORRECT ANS- - Carbohydrate composition of antigens True or False: Growth media is best suited for distinguishing between two similar species of bacteria. - - CORRECT ANS- - False A researcher is asked to determine which of two vials contains E coli and which contains Salmonella. Knowing both are Gram-Negative while only one of them is capable of fermenting lactose, which type of media would be best suited? - - CORRECT ANS- - Differential media What are the requirements of a fastidious microbe? - - CORRECT ANS- - Enriched medias, as a fastidious microbe is an organism with complex growth requirements such that if absent it will not grow.
True or False: LB agar is classified as a non-selective, non-differential media. - - CORRECT ANS- - True. The polysaccharide-based hardening agent added to LB media to produce LB agar is derived from what? - - CORRECT ANS- - Seaweed (algae) extract. Blood agar is which type of medium? - - CORRECT ANS- - Differential and enriched Columbia CNA agar is most closely related to which media: - - CORRECT ANS- - BAP A researcher is studying a strain of E. coli currently growing on a MacConkey plate. However, the researcher can't remember if E. coli is Gram-Positive or Gram-Negative. Would a Gram stain be necessary to confirm? Why or why not? - - CORRECT ANS- - No. A Gram stain would not be necessary, as only Gram-Negative microbes will grow on MacConkey agar. Thus, E. coli is a Gram-Negative microbe. In an attempt to detect the presence of the pathogenic strain of E. coli O157:H7, a researcher spread a culture onto a MacConkey agar with failed results. What type of agar should they (correctly) try next? Why? - - CORRECT ANS- - The microbe should be plated on SMAC (Sorbitol-MacConkey agar) as it is specifically formulated to detect O157:H7. Pathogenic E. coli (O157:H7) cannot ferment sorbitol while 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). In Eosin Methylene Blue (EMB) agar, what color indicates the presence of E. coli - - CORRECT ANS- - Metallic Green. Which type of agar media is best suited to support the growth of Staphylococcus? - - CORRECT ANS- - Mannitol salt agar
False. While staphylococcus can be found in ~30% of the human population, it remains non-symptomatic. - - CORRECT ANS- - False When a bacterium neither harms nor benefits from the host from which it obtains nutrients, it is referred to as being ___________. - - CORRECT ANS- - Commensal. True or False. Tuberculosis is best identified by a Gram stain. - - CORRECT ANS- - False True or False. Directly ingesting clostridium or its associated spores will not cause illness in adults. - - CORRECT ANS- - True True or False. There are currently no cures for tetanus - - CORRECT ANS- - True. Identify the medical condition characterized by robust carbohydrate fermentation under anaerobic conditions, swelling of the infected areas and fever. - - CORRECT ANS- - Gas gangrene The alpha-toxin perfringolysin is associated with which medical condition caused by Gram- positive anaerobic bacteria? - - CORRECT ANS- - Gas gangrene. Which form of the plague is highly virulent? What does it target? - - CORRECT ANS- - Pneumonic plague is highly virulent and targets the respiratory (lungs) system. Syphilis is caused by: - - CORRECT ANS- - spirochete Treponema pallidum True or False. Chlamydia is an obligate parasite and as such can be grown on agar plates alone. - - CORRECT ANS- - True or False. Chlamydia is an obligate parasite and as such can be grown on agar plates alone.
Match the following diseases with their respective symptoms if left untreated:A. Paralysis, blindness and dementia C. Cardiac and neurological complications E. Infertility and pelvic inflammatory disease. - - CORRECT ANS- - A=syphilis C = Gonorrhea E=chlamydia The envelope surrounds the _________ of some viruses. - - CORRECT ANS- - Capsid Rank the following viruses based on their size from largest to smallest: Paramyxovirus Poliovirus Smallpox virus - - CORRECT ANS- - Smallpox virus > Paramyxovirus > Polio Virus Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step. - - CORRECT ANS- - 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 3 - Uncoating: the viral capsid disassembles 4 - Replication: the viral genome is the 'blueprint' to make copies of itself 5 - Release: New virus particles are produced and leave the cell 6 - New infection: newly produced viruses that left the host cell now go on to infect new cells. A virus that infects bacteria is called a ____________ and contains a _____-side polygon capsid. - - CORRECT ANS- - Bacteriophage; 20-sided Name all parts of the bacteriophage - - CORRECT ANS- - 1 - Capsid (or Head) 2 - Collar 3 - Tail (sheath) 4 - Base plate
neuraminidase proteins? Why? - - CORRECT ANS- - Neuraminidase (N) proteins are directly involved in the budding and release of new viral particles and would thus be the correct target. Hemagglutinin (HA) proteins would not be advisable targets as they are directly involved in viral attachment and entry into the host cell. Explain why the flu shot given each year may not be 100% effective at preventing the flu? - - CORRECT ANS- - It is possible to receive a flu vaccine and yet (unfortunately) still get the flu in the same season if you are exposed to a viral strain that was not included in the vaccine. There are a large number of variants and the flu vaccine is unable to vaccinate against all subtypes. Medical researchers predict and then distribute flu vaccines based current trends and the available data relative to the most common circulating strains. Unfortunately, this model is not always 100% accurate. True or False. The viral capsid of HIV is cone shaped and contains ~2,000 copies of the viral protein p24. - - CORRECT ANS- - True The HIV surface glycoprotein gp41 binds what host cellular receptor? A. CD B. CXCR C. CD D. CXCR5 - - CORRECT ANS- - B. HIV gp41 binds to the receptor CXCR An individual infected with HIV is placed on anti-retroviral medication. Describe how the medication will affect the virus - - CORRECT ANS- - As the name suggests, anti-retrovirals are intended to inhibit (anti) the process of reverse-transcription (retro). Once the virus enters the cell and uncoating is complete, the viral enzyme reverse transcriptase (RT) acts on the two RNA copies, creating a complementary DNA strand. Anti-retrovirals attempt to block this step. In the absence of anti-retroviral medications, the now double-stranded DNA is transported to the nucleus where it can integrate into the host genome and begin replicating. By inhibiting the process of RT, anti-retroviral medications effectively block the production of new viruses by preventing its integration and replication.
A virus is classified as a microbe - - CORRECT ANS- - True. Although viruses are not living and as such are not considered microorganisms, they can, however, be classified as microbes, a more general term that includes microorganisms and viruses. Proteins are formed from various combinations of __________ of which there are ____ known forms. - - CORRECT ANS- - Amino acids, 20 How many amino acids are classified as being essential amino acids? - - CORRECT ANS- - 9 Where can the two major types of nucleic acids be found in the cell and what are their roles? - - CORRECT ANS- - RNA is capable of leaving the nucleus. 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. Complete the following DNA strand and indicate how many bonds are formed for each complementary pair: 3' GGTCATCG 5' 5' CC AGC 3' - - CORRECT ANS- - 3' GGTCATCG 5' 5' CCAGTAGC 3' There are 2 bonds formed between A and T, and 3 bonds between G and C. The plasma membrane (select all that are true): A. Restricts movement of materials in and out of the cell B. Is often a triple layer comprised of lipids C. Prevents essential nutrients from escaping
True or False: During fermentation one means of eliminating pyruvate is by converting it into lactic acid. - - CORRECT ANS- - True Giemsa staining is used to detect each of the following except a. Neisseria Gonorrhea b. Chlamydia trachomatis c. Histoplasma d. Malaria - - CORRECT ANS- - a. Neisseria Gonorrhea What STD is caused by a Gram-negative spirochete that can lead to paralysis, blindness, and dementia? - - CORRECT ANS- - Syphilis Maintaining a temperature of 37 deg C is optimal for promoting growth and is the temperature most commonly used by researchers. Describe an alternative incubation technique used to isolate a bacterium. - - CORRECT ANS- - Unlike bacteria, other organisms such as yeast preferentially grow at 30 deg C. Additionally, because pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37deg C, researchers may set incubators at 25deg C to restrict pathogenic growth. True or False. If false, make it true. The metabolism of a lipid-derived carbon atom will yield more ATP than a molecule of glucose. - - CORRECT ANS- - True Which of the following is/are true of Fungi? (select all that apply) a. Yeast is an example b. They are autotrophic. c. They are only unicellular
d. Cell walls are composed of chitin - - CORRECT ANS- - a. Yeast is an example d. Cell walls are composed of chitin Targets the CNS, temporary or permanent paralysis - - CORRECT ANS- - Polio (poliomyelitis) Viral reactivations of the dormant VZV virus - - CORRECT ANS- - Shingles (Herpes zoster) First infectious disease eradicated in 1977 through global vaccination - - CORRECT ANS- - Smallpox (Variola virus) Characterized by blisters covering the entire body - - CORRECT ANS- - Chickenpox (varicella-zoster) Which region in a four phase dilutional streak contains the highest concentration of a microbial organism? Describe the technique that is used in pulling the sample from one phase to the next. - - CORRECT ANS- - The first phase of the quadrant streak contains the highest concentration of a microbial organism. Using a new sterile loop, part of the sample is pulled from region 1 to region 2. This process is repeated again each time using a new sterile loop through the remaining regions. Which of the following reactions is an example of transferase? a. A + B - > A-B b. A-B + H2O - > A-OH + B-H c. A- + B - > A + B- d. Ab + C - > A + Cb - - CORRECT ANS- - d. Ab + C - > A + Cb
True or False. If false, make it true. Glucose is an example of a disaccharide. - - CORRECT ANS- - False. Glucose is an example of a monosaccharide. This agar is a derivative of TSA whereby mammalian blood, often from sheep, is added to the plate. It may have a distinct red coloration. The media promote the growth of fastidious microorganisms, such as various strains of Streptococcus. - - CORRECT ANS- - Blood Agar Also known as lysogeny broth, it is a multi-purpose media capable of growing a wide variety of microorganisms - - CORRECT ANS- - LB Agar These plates contain red blood cells that have been lysed by heat. - - CORRECT ANS- - Chocolate Agar This agar is red in color and is classified as both a selective and differential form of media. The agar restricts the growth of Gram-positive bacteria. Microorganisms are differentiated based on their ability to ferment the lactose present in the media. - - CORRECT ANS- - Eosin Methylene Blue Agar What coronavirus-associated infection gave rise to quarantining and travel restrictions in 2003? - - CORRECT ANS- - SARS Bacteria that have a round morphology are referred to as _____________. - - CORRECT ANS- - Coccus Explain the difference between a simple stain and a wet mount stain technique. When would each be indicated for use? - - CORRECT ANS- - Simple staining uses a solution of a positively charged dye, such as methylene blue, crystal violet, safranin, or fuchsin to bind
to and stain the negatively charged membrane of the microorganism. This simple technique is often used to quickly observe the size, shape, and arrangement of cells. Wet mount is a basic form of sample preparations for viewing live samples. A small liquid culture (usually just a drop) containing a microorganism of interest is prepared, added to a slide, and then covered with a glass coverslip. The coverslip is present to both protect the objective and the specimen while also holding the microorganism in place. Each of the following statements about respiration is true, except: a. It does not produce ATP. b. It produces NADH and FADH2 in abundance. c. Is is an aerobic process. d. The central cycle is called Tricarboxylic Acid Cycle - - CORRECT ANS- - a. It does not produce ATP. Describe the TWO main characteristics of LYSOGENIC (temperate) bacteriophage replication. - - CORRECT ANS- - 1. Exist in a non-replicative state that does not kill the host cell.
- Integrated into the host genome but production of viral proteins in suppressed. List the 4 nitrogenous bases found in RNA and describe how they pair with one another. - - CORRECT ANS- - The four nitrogenous bases found in RNA are Adenine (A), Uracil (U), Cytosine (C), and Guanine (G). A pairs with U, and G pairs with C. True or False. If false, make it true. When grown on Blood Agar Plates (BAP), microbes capable of delta hemolysis designate the absence or lack of hemolytic activity, and the resulting colonies are often white/tan in
