Nokea
Which type of cell produces antibodies?
- A. Helper T cells
- B. Plasma cells
- C. Cytotoxic T cells
- D. Regulatory T cells
Correct Answer: B
Rationale: The correct answer is B: Plasma cells. Plasma cells are a type of white blood cell that produces antibodies in response to antigens. They are essential in the immune response to help fight off infections and other diseases. Helper T cells (A) assist other immune cells but do not directly produce antibodies. Cytotoxic T cells (C) are responsible for killing infected cells, not producing antibodies. Regulatory T cells (D) help regulate the immune response but do not produce antibodies. In summary, only plasma cells are specifically designed to produce antibodies in the immune system.
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The three antibiotic-resistant bacteria that are of most current concern in North America are ____________________, ____________________, and ____________________.
- A. Methicillin-resistant Staphylococcus aureus (MRSA)
- B. Carbapenem-resistant Enterobacteriaceae (CRE)
- C. Vancomycin-resistant Enterococcus (VRE)
- D. All of the above
Correct Answer: D
Rationale: The correct answer is all of the above. MRSA, CRE, and VRE are among the most concerning antibiotic-resistant bacteria in North America due to their prevalence and difficulty in treatment.
What drives the emergence of immuno-resistant pathogen strains?
- A. Host immune system failure
- B. Slow mutation rates in pathogens
- C. Rapid pathogen reproduction and mutations
- D. Absence of host immune adaptation
Correct Answer: C
Rationale: The correct answer is C: Rapid pathogen reproduction and mutations drive the emergence of immuno-resistant pathogen strains. This is because the high rate of reproduction allows for more opportunities for mutations to occur, some of which may confer resistance to the host's immune system or medical interventions. Slow mutation rates in pathogens (B) would not lead to the rapid emergence of resistant strains. Host immune system failure (A) occurs after the pathogen has already developed resistance. The absence of host immune adaptation (D) does not directly drive the emergence of resistant strains as it is the rapid reproduction and mutations of pathogens that play a crucial role.
A major effector function of TH2 cells is:
- A. Protection against intracellular bacteria
- B. Protection against parasitic worms
- C. Regulation of the adaptive immune response through the secretion of anti-inflammatory cytokines
- D. Activation of macrophages
Correct Answer: B
Rationale: The correct answer is B because TH2 cells play a crucial role in protecting against parasitic worms by secreting cytokines that promote eosinophil activation and antibody production. This response helps to expel the parasites from the body.
Incorrect choices:
A: TH1 cells are responsible for protection against intracellular bacteria.
C: TH3 cells, not TH2 cells, are known for secreting anti-inflammatory cytokines.
D: Activation of macrophages is primarily mediated by TH1 cells through IFN-gamma secretion.
The way in which some organism supplies some other organism with food and energy known as
- A. Food chains
- B. Food Network
- C. Pyramid of power
- D. levels of nutrition
Correct Answer: A
Rationale: The correct answer is A: Food chains. A food chain depicts the flow of energy and nutrients from one organism to another in an ecosystem. It shows how energy is transferred from producers to consumers. Food network (B) is a more complex and interconnected system than a simple linear chain. Pyramid of power (C) represents the energy flow in an ecosystem, not the transfer of food. Levels of nutrition (D) is not a term commonly used to describe how organisms transfer food and energy.
What is the function of MHC molecules on antigen-presenting cells?
- A. Secreting cytokines
- B. Binding and destroying pathogens
- C. Displaying antigen fragments for T cell recognition
- D. Producing antibodies
Correct Answer: C
Rationale: The correct answer is C, displaying antigen fragments for T cell recognition. MHC molecules bind to antigen fragments and present them on the cell surface for T cells to recognize. This process is crucial for activating the immune response. Choice A is incorrect as MHC molecules do not secrete cytokines. Choice B is incorrect as MHC molecules do not directly destroy pathogens. Choice D is incorrect as MHC molecules do not produce antibodies; that is the function of B cells.