WGU OA D311 Microbiology Study Review Exam 2026

WGU OA D311 Microbiology Study Review Exam 2026 What is the significance of microorganisms containing a thick coat of peptldogiywn within the cell wall? - Correct Answer-Microorganisms containing a thick coat of peptidoglycan within the cell wall are typically classified as gram-positive bacteria. Why are viruses considered acellular? - Correct Answer-They cannot reproduce without a host. What is the defining characteristic of eukaryotes? - Correct Answer-They have a nucleus. Which microorganism can cause vaginal yeast Infections and oral thrush? - Correct Answer-Fungi Why can it be difficult to determine the etiologic agent of a disease? - Correct Answer Some signs and symptoms can be caused by many different etiologic agents. What kind of staining technique Is the acid-fast stain? - Correct Answer-differential staining technique used to distinguish between acid-fast and non-acid-fast bacteria based on the presence of mycolic acid in their cell walls. The high lipid content of acid fast organisms, like Mycobacterium, requires special stains, such as Carbolfuchsin, to penetrate their waxy cell walls A doctor prescribed antibiotics for a patient complaining of runny nose. fever. and aches and pains. Which type of infection did the doctor suspect? - Correct Answer-The doctor likely suspected a bacterial infection because antibiotics are not effective against viral infections. A healthcare professional is treating a patient who developed a yeast infection after taking antibiotics. What type of medication should be prescribed to this patient? - Correct Answer-Antifungals Which structure promotes motility in Proteus. Shigelia. and Salmonella species. all of which can cause serious disease in humans? - Correct Answer-Presence of flagella Which bacterial virulence factor allows a strain to resist phagocytosis, increasing the organism's virulence? - Correct Answer-Capsule production Why is treating Haemophilus influenzae difficult? - Correct Answer-The capsule is antiphagocytic. WGU D311 WGU D311 How do pili aid pathogens in causing disease? - Correct Answer-They cause pathogens to adhere to host cells. Which virulence factor allows pathogens to penetrate the dermis and invade the body? - Correct Answer-Bacterial enzymes A bacterium from a deep-sea hydrothermal vent has been cultured. Which staining technique should be used to begin the process of species identification? - Correct Answer-Gram staining What does the presence of a clear area around a cell stained with India ink indicate about the cell? - Correct Answer-The cell has a capsule. How do basic stains work? - Correct Answer-The positively charged stain is attracted to the negatively charged portion of the cell. Which staining technique is used to distinguish bacteria based on their ability to produce structures that can survive extreme heat stress? - Correct Answer-Endospore stain Which aspect of a staining protocol enables dye to penetrate an endospore? - Correct Answer-Heat Why are the relationships between pathogenic microbes and their hosts considered parasitic? - Correct Answer-The microbe benefits from the interaction while the host is harmed. Which characteristic of dracunculiasis has been pivotal to the success of its eradication campaign? - Correct Answer-Dracunculiasis has no animal reservoir. Which type of organism would be most likely to grow on food stored in a refrigerator or freezer? - Correct Answer-A psychrophile would be most likely to grow on food stored in a refrigerator or freezer as these microorganisms thrive in cold temperatures. Staphylococcus epidermldls is a member of the human resident microbiota and considered part of the human innate immune system. S. epldermidis uses our dead skin cells as a source of nutrients. What type of relationship between S. epidermidis and humans is described above? - Correct Answer-The type of relationship between Staphylococcus epidermidis and humans described above is "Commensalism," where one organism (S. epidermidis) benefits (uses dead skin cells) without harming the other organism (humans). Commensalism WGU D311 WGU D311 Why is the production of lactic acid by the resident microbe Lactobacillus Important to human health? - Correct Answer-Lactic acid is important to human health because it inhibits the growth of pathogenic yeasts. Which type of infections are prevented by proper sterilization of hospital equipment and healthcare worker handwashing? - Correct Answer-Nosocomial infections are prevented by proper sterilization of hospital equipment and healthcare worker handwashing. A patient Is determined to have contracted Lyme disease after being bit by an infected tick. What type of transmission is described in this scenario? - Correct Answer-Vector transmission is described in this scenario. Which is a description of vehicle transmission? - Correct Answer-A person drinks untreated water on vacation and later has diarrhea and nausea is a description of vehicle transmission. Which organism type contains species that perform adhesion through the unique use of its flagella to move out fluid from under a large adhesive disc, resulting in lower pressure to adhere to the intestinal lining? - Correct Answer-Protozoa A patient presents to the emergency department with high fever. difficulty breathing. vomiting, coughing up blood. and severe chest pain when inhaling. Which pathogen would the provider suspect? - Correct Answer-Bacillus anthracis Which activity of the complement system would be useful against an infection caused by a gram-negative bacterium? - Correct Answer-Membrane attack complex Which body system is protected by the ciliary escalator? - Correct Answer-Respiratory What is the role of global public health organizations in eradication of diseases, like polio? - Correct Answer-Organize vaccination campaigns and programs Malaria cases are routinely found in certain areas of the world but are not seen In other areas. How would malaria be described in those areas where it is found? - Correct Answer-Endemic A hospital notices an increase in patients being admitted with gastrointestinal symptoms and dehydration over a two-week period. An epidemiological analysis reveals that the cause is the same pathogen, but that none of the hospitalized individuals were ever in the same location at the same time. What is an explanation for this analysis? - Correct Answer-These individuals all consumed contaminated food from a common manufacturing source. Which action is an innate physical defense? - Correct Answer-Mucous secretions trapping and removing microbes from the respiratory tract. WGU D311 WGU D311 Which vaccine type would be effective against an organism that can produce a capsule? - Correct Answer-Conjugate Which protocol for microbial growth control leaves the least number of living cells? - Correct Answer-Sterilization Which type of microbial control is necessary for surgical equipment? - Correct Answer Sterilization How are spore-forming bacteria killed to make canned foods safe for consumption? - Correct Answer-Heat and pressure Which type of microbial control is used in a variety of situations, from doorknobs to swimming pools to diaper cream. to prevent the growth and spread of microbes? - Correct Answer-Phenolics Why is boiling not used as a sterilization method In clinical settings? - Correct Answer Boiling is not effective against endospores. Why do beta-lactamase-producing pathogens cause public concern for a community? - Correct Answer-Beta-lactamase is an enzyme that protects the pathogen from some common antibiotics. Why are antlhelmlnthlc drugs difficult to develop? - Correct Answer-Helminths are eukaryotes, and it is difficult to develop medications with selective toxicity for them. Which pathogen is susceptible to beta-lactam antimicrobials? - Correct Answer Prokaryotic pathogens are susceptible to beta-lactam antimicrobials. Which process is targeted by antivirals? - Correct Answer-Antivirals target the process of nucleic acid synthesis in viruses. Which term describes how bacteriostatic antibiotics become bactericidal when the drugs are used together? - Correct Answer-The term that describes how bacteriostatic antibiotics become bactericidal when used together is "Synergism." How can pathogens typically found in animal feces, such as hantavlrus, be transmitted through air? - Correct Answer-Dried fecal particles are carried on dust and inhaled by humans. Which cellular component is conjugated to protein antigens to improve efficacy In the conjugate vaccine. especially for children under the age of two? - Correct Answer Capsule polysaccharide What is the disadvantage of a live attenuated vaccine? - Correct Answer-Risk of reversion WGU D311 WGU D311 How do vaccines help the body fight against viruses? - Correct Answer-By training the adaptive immune system Which vaccine type would be useful against a toxin-producing strain of bacteria? - Correct Answer-Toxoid vaccine Which vaccine type would result in both a cell-mediated and humoral immune response because pathogens are able to grow in the host? - Correct Answer-Attenuated viral vaccine Why would conjugate vaccines have higher efficacy than a subunit vaccine for the same pathogen? - Correct Answer-Conjugate vaccines combine an antigen that creates a weak immune response with an antigen that creates a strong immune response, which can result in higher efficacy compared to a subunit vaccine for the same pathogen. When is herd immunity achieved? - Correct Answer-Herd immunity is achieved when the immune portion of a population renders unimmunized members protected. Which bacterial structure allows the bacteria to move? - Correct Answer-Flagella Which type of eukaryotic microorganism can cause skin infections but typically causes an opportunistic infection? - Correct Answer-Fungi A patient presents with an unknown infection. A microscopic examination of the pathogen reveals that it is single-celled, has a nucleus, but does not have a cell wall. What type of microorganism is it? - Correct Answer-Protozoa Cystic fibrosis can be treated with gene therapy. Which microorganism is involved in this process? - Correct Answer-Virus Hantavirus causes a deadly pulmonary infection, while Streptococcus pyogenes causes pharyngitis. Which of the following statements is true? - Correct Answer-Hantavirus is more virulent than Streptococcus pyogenes Which of the following is a virulence factor that helps the pathogen spread into new areas of the body to cause infection? - Correct Answer-Clostridium perfringens' collagenase Vibrio cholerae produces an enterotoxin which causes the symptoms of cholera. With no other information, what is true about the cholera toxin? - Correct Answer-It has a low median lethal dose Which is NOT associated with biofilms? - Correct Answer-Dracunculus medinensis causing dracunculiasis WGU D311 WGU D311 A patient presents with muscle weakness, nausea, and vomiting. They report that they recently ate food that they previously canned, and they were concerned that they did not apply enough heat or pressure. This leads you to suspect Clostridium botulinum as the pathogen. Clostridium botulinum is known to survive harsh environmental conditions. What stain would you use to confirm? - Correct Answer-Endospore stain Which staining technique uses the negative dye india ink? - Correct Answer-Capsule A lab technician performs a Gram stain on a patient sample. They see purple bacillus shaped organisms. What structure does this microorganism possess? - Correct Answer Thick layer of peptidoglycan Pregnant women are advised to not eat deli meat, due to the potential to contract listeriosis. Listeria monocytogenes will grow on refrigerated food. What group of microorganisms is this bacterium most likely associated with? - Correct Answer Psychrophile Staphylococcus epidermidis is part of the resident microbiota of our skin. What type of relationship do we have with Staphylococcus epidermidis? - Correct Answer Commensalism While enjoying the park, a mother feeds her toddler a sandwich. The toddler takes his time eating, and a fly lands on the sandwich. The toddler later starts exhibiting gastrointestinal symptoms. What type of transmission is this? - Correct Answer Mechanical vector transmission A patient is brought to the hospital with fever, joint stiffness, and swollen lymph nodes. None of their family members are sick, even though they had close contact with the patient. The family had gone camping the week before. The doctor suspects Lyme disease, which is confirmed through testing. What type of disease is this? - Correct Answer-Noncommunicable Diplococcus pneumoniae has two forms. One form produces a capsule and is more deadly than the form that does not produce a capsule. Why is the capsulated form more deadly? - Correct Answer-The capsules prevent the bacteria from phagocytosis A patient comes into the ER and reports pain, nausea, trouble breathing, and malaise. Through testing, the patient's body temperature, breathing rate, oxygen saturation, and abdominal features are measured. Based on this information, which of the patient's reported symptoms was also a sign? - Correct Answer-Trouble breathing Which innate immune component would be most effective against a Gram negative infection? - Correct Answer-The complement system Which of the following is a chemical defense of the lungs? - Correct Answer-Lysozyme WGU D311 WGU D311 Chagas diseases is caused by a Trypanosoma cruzi, a protozoa found in Mexico. What type of disease is Chagas? - Correct Answer-Endemic Several members of a family attending a reunion are admitted to the ER with gastrointestinal symptoms. When questioned, it is discovered that the ill members of the family ate potato salad, but the nonaffected family members did not. What would this be an example of? - Correct Answer-Point source spread Which type of control protocol would be safe for living tissue? - Correct Answer Antisepsis Which of the following would limit the numbers of microorganisms but would not kill all of them? - Correct Answer-Refrigeration .Which type of chemical control method is used in a large variety of places to prevent the growth of pathogens, including water storage, wound care, baby powder, newborn eye protection, and swimming pools? - Correct Answer-Metals Which of the following statements about broad-spectrum and narrow-spectrum antibiotics is true? - Correct Answer-Broad-spectrum antibiotics are given prophylactically with surgical procedures A patient is diagnosed with strep throat, which is caused by Streptococcus pyogenes, a Gram-positive bacterium. What would be the best course of treatment? - Correct Answer-Amoxicillin What is the most common way that bacteria resist penicillin? - Correct Answer Producing beta-lactamases Which target is a good option for a drug that treats a yeast infection, since it will make the drug selectively toxic? - Correct Answer-Ergosterol A 5th grader is in a waiting room when an infant with whooping cough is brought in. Whooping cough is highly contagious bacterial disease, but the child does not get it. What is the most likely explanation? - Correct Answer-The child has memory B cells due to getting the DTaP vaccine. A patient that is undergoing chemotherapy steps on broken glass while walking barefoot outside. It results in a cut that requires stitches. The doctor tells you to give the patient a tetanus vaccine, but an intern stops you before you can. He voices his concern about giving the vaccine to someone on chemotherapy. The doctor explains that it is safe because of the type of vaccine. What type of vaccine is the tetanus vaccine? - Correct Answer-Toxoid Which of the following agents denature proteins and disrupt membrane integrity? - Correct Answer-Alcohols WGU D311 WGU D311 Antibiotics should be sterilized using which method? - Correct Answer-Membrane filtration Contact lens cleaners commonly contain which endospore-killing chemical agent? - Correct Answer-Peroxygens Which of the following drugs inhibits cell wall synthesis? - Correct Answer-Penicillin Which of the following drugs inhibits nucleic acid synthesis? - Correct Answer fluoroquinolone Which structure is a common target of antifungal drugs? - Correct Answer-ergosterol What does the rabies vaccine contain? - Correct Answer-dead or inactivated whole pathogen Which vaccine type was developed primarily to enhance the effectiveness of subunit vaccines in young children? - Correct Answer-conjugate After antigen presentation and activation, antibodies are produced and secreted by which cells? - Correct Answer-plasma B cells What is the mode of transmission for Plasmodium? - Correct Answer-being bitten by mosquitoes Malarial disease in Brazil is an example of which type of disease? - Correct Answer endemic A person with influenza sneezes, and the respiratory secretions travel half a meter before being breathed in by another person, who later comes down with the flu. What type of transmission has occurred? - Correct Answer-droplet transmission Which of the following is a physical defense of the respiratory system? - Correct Answer-Mucociliary escalator Which of the following is a source of vitamin K for humans? - Correct Answer Escherichia coli in their digestive tract produces vitamin K Which term best describes the relationship between pathogenic bacteria and humans? - Correct Answer-parasitism After getting treatment for strep throat, a patient discovers that they have white patches on their throat. They are diagnosed with thrush, a fungal infection. What type of infection is thrush? - Correct Answer-secondary infection WGU D311 In which category is the exotoxin that produces toxic shock syndrome? - Correct Answer-superantigens Which adhesin is used by Streptococcus mutans to cause dental caries? - Correct Answer-adhesin P1 Most mushrooms and puffballs are members of which fungal phylum? - Correct Answer basidiomycota Which describes the condition in which blood contains actively dividing bacteria? - Correct Answer-septicemia Chickenpox is a typically mild disease caused by varicella zoster virus. The major symptom is an itchy, blister-like rash. Rabies is a fatal disease caused by the rabies virus. Symptoms include aggression, hydrophobia, and eventually death is the vaccine is not administered quickly. Both viruses infect neurons. Based on this information, which statement is true? - Correct Answer-Rabies virus is more virulent than varicella zoster virus Property of a virus is..... - Correct Answer-it is an infectious cellular pathogen Which two structures do all viruses contain? - Correct Answer-nucleic acid and capsid The Gram-staining procedure is best described as which of the following? - Correct Answer-differential staining Which of the following most specifically refers to a stain that dyes a specimen rather than the background? - Correct Answer-positive stain WGU D311