microbiology chapter 11 test bank

Correct Answer: D

Rationale: Rationale: 1. Rickettsiae are obligate intracellular bacteria, hence they do not form spores, capsules, or flagella. 2. They have a slim glycocalyx layer, aiding in attachment to host cells. 3. Bipolar fimbriae are structures that help in adhesion to host cells. Therefore, all statements (A, B, and C) are true for Rickettsiae, making option D the correct answer. Other choices are incorrect as they do not accurately describe the characteristics of Rickettsiae.

Correct Answer: A

Rationale: The correct answer is A: Neutralization. In this experiment, the researchers used antitoxic antibotulinic serum of different types to neutralize the botulinic toxin in tinned meat extract injected into mice. Neutralization is the process of rendering a toxin harmless by combining it with specific antibodies. The purpose of injecting the antitoxic serum was to neutralize the toxin and prevent it from causing harm to the mice. This serological reaction of neutralization directly aligns with the objective of the experiment. Summary of other choices: B: Precipitation - Precipitation involves the formation of a visible insoluble complex when an antigen reacts with its corresponding antibody. This process was not described in the scenario. C: Complement binding - Complement binding involves the activation of the complement system by antigen-antibody complexes. This was not the main focus of the experiment described. D: Double immune diffusion - This technique is used to detect the presence of specific antigens or antibodies

Correct Answer: C

Rationale: The correct answer is C: peroxisomes. Peroxisomes contain enzymes involved in breaking down fatty acids and detoxifying harmful substances. They do not contain digestive enzymes. Lysosomes contain digestive enzymes involved in breaking down waste materials. Chloroplasts are involved in photosynthesis and do not contain digestive enzymes. Mitochondria are involved in energy production and do not contain digestive enzymes. Therefore, the correct answer is peroxisomes.

Correct Answer: A

Rationale: The correct answer is A: IgG. Anti-tetanus gamma globulin is produced by hyperimmunization, leading to a high concentration of specific antibodies, predominantly IgG. IgG is the most abundant immunoglobulin in the blood and provides long-term immunity against tetanus. IgA is mainly found in mucosal areas, not in gamma globulin preparations. IgM is the first antibody produced in response to an infection and is not the prevailing class in this preparation. IgE is associated with allergic reactions and parasitic infections, not with anti-tetanus immunity.

Correct Answer: B

Rationale: The correct answer is B: Staphylococcus aureus. This bacterium is known as a common cause of hospital-acquired infections due to its ability to colonize the skin and mucous membranes of healthcare workers and patients. Staphylococcus aureus can cause various infections, including surgical site infections and bloodstream infections, in healthcare settings. Rationale: 1. Clostridium botulinum is known for causing foodborne botulism, not hospital-acquired infections. 2. Treponema pallidum causes syphilis, which is primarily transmitted through sexual contact, not hospital settings. 3. Mycobacterium leprae causes leprosy, which is not commonly associated with hospital-acquired infections. In summary, Staphylococcus aureus is the correct answer as it is a common cause of hospital-acquired infections due to its prevalence in healthcare environments, unlike the other choices which are not typically associated with hospital-acquired infections.