Nokea
What type of cell is responsible for carrying oxygen and carbon dioxide in the body?
- A. Red blood cell
- B. White blood cell
- C. Platelet
- D. Hematocrit
Correct Answer: A
Rationale: The correct answer is A: Red blood cell. Red blood cells, also known as erythrocytes, contain hemoglobin that binds to oxygen and carbon dioxide for transport in the bloodstream. They are specifically designed for gas exchange. White blood cells (B) are part of the immune system and fight infections. Platelets (C) are responsible for blood clotting. Hematocrit (D) refers to the proportion of red blood cells in the blood, not a specific type of cell responsible for gas transport.
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Defensins are
- A. Released by mast cells during an allergic reaction
- B. Membrane-disrupting peptides
- C. Acute phase proteins
- D. Opsonins
Correct Answer: B
Rationale: The correct answer is B: Membrane-disrupting peptides. Defensins are antimicrobial peptides that disrupt bacterial cell membranes. This disrupts the integrity of the bacterial cell, leading to cell lysis and death. Choice A is incorrect because mast cells release histamines, not defensins. Choice C is incorrect as acute phase proteins are involved in the immune response to inflammation. Choice D is incorrect as opsonins are molecules that enhance phagocytosis of pathogens by immune cells.
What are the recommended measures to prevent the transmission of health care–associated infections (HAIs) (select all that apply)?
- A. Empty bedpans as soon as possible
- B. Use personal protective equipment
- C. Hand washing or alcohol-based sanitizing
- D. Have patients wear sandals in the shower
Correct Answer: B
Rationale: The correct answer includes options B and C. Using personal protective equipment and practicing proper hand hygiene are critical measures to prevent HAIs. Emptying bedpans promptly and having patients wear sandals in the shower are not directly related to preventing HAIs.
When comparing the types of viruses that infect bacteria, plants, and vertebrate animals, what trends appear from bacterial to vertebrate viral groups?
- A. Less complex-type forms
- B. more enveloped forms
- C. fewer enveloped forms
- D. same number of DNA-containing forms
Correct Answer: B
Rationale: The correct answer is B: more enveloped forms. This trend can be explained by the complexity of host organisms. Bacteria have simple cell structures, making enveloped viruses less common. As we move from bacteria to plants and vertebrate animals, the complexity of host cells increases, leading to a higher prevalence of enveloped viruses. This trend is due to the need for enveloped viruses to evade the host's immune system and facilitate entry into host cells. Choices A, C, and D are incorrect because they do not consider the relationship between virus structure and host complexity.
Which of the following is not a systemic cytokine?
- A. TNF
- B. IL-1
- C. IL-6
- D. IL-8
Correct Answer: D
Rationale: The correct answer is D: IL-8. IL-8 is not a systemic cytokine because it mainly acts locally at the site of inflammation to recruit neutrophils. Systemic cytokines like TNF, IL-1, and IL-6 have widespread effects throughout the body, influencing various immune responses and inflammatory processes. IL-8's localized action distinguishes it from systemic cytokines, making it the correct choice. TNF, IL-1, and IL-6 are all systemic cytokines that play key roles in regulating the immune response and inflammation at a systemic level, unlike IL-8.
The major role of the complement system is to work in conjunction with
- A. antibodies to lyse cells via the C8 and C9 components
- B. the major histocompatibility complex for cell recognition
- C. antibodies to opsonize cells
- D. the T-cell receptor for production of lymphokines
Correct Answer: A
Rationale: Rationale: The complement system is a group of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens. Choice A is correct because the C8 and C9 components of the complement system form the membrane attack complex which lyses cells. Choices B, C, and D are incorrect because the complement system primarily functions independently of the major histocompatibility complex, antibodies for opsonization, and T-cell receptor for lymphokine production.