Nokea
Where do T cells mature?
- A. Bone marrow
- B. Thymus
- C. Spleen
- D. Lymph nodes
Correct Answer: B
Rationale: The correct answer is B: Thymus. T cells mature in the thymus, where they undergo selection and maturation processes essential for their function in the immune system. The thymus provides a specialized environment for T cell development, including positive and negative selection to ensure self-tolerance and functional T cell repertoire.
A: Bone marrow is incorrect because it is the site of B cell maturation, not T cells.
C: Spleen is incorrect as it acts as a secondary lymphoid organ for immune response but not the site of T cell maturation.
D: Lymph nodes are incorrect as they are important for immune surveillance and activation but not the primary site for T cell maturation.
You may also like to solve these questions
If you were to observe the activity of methylated DNA, you would expect it to
- A. be unwinding in preparation for protein synthesis.
- B. be replicating nearly continuously.
- C. have turned off or slowed down the process of transcription.
- D. induce protein synthesis by not allowing repressors to bind to it.
Correct Answer: C
Rationale: The correct answer is C because methylation of DNA typically results in the inhibition or slowing down of transcription. Methylated DNA attracts proteins that bind to it, preventing transcription factors from accessing the DNA and initiating transcription. This interference with the transcription process leads to gene silencing or reduced gene expression.
A: DNA unwinding in preparation for protein synthesis is unrelated to DNA methylation.
B: Continuous replication is not a typical consequence of DNA methylation.
D: Methylation does not directly induce protein synthesis but rather affects transcription by influencing gene expression.
The precursor of IL-1β is processed to its active form by
- A. Pro-caspase 1
- B. Caspase 1
- C. Procaspase 8
- D. Caspase 8
Correct Answer: B
Rationale: The correct answer is B: Caspase 1. Caspase 1 is responsible for the cleavage of pro-IL-1β into its active form IL-1β. This process involves the activation of Caspase 1 by various inflammasomes upon sensing danger signals. Pro-caspase 1 (Choice A) is the inactive precursor form of Caspase 1 and is not involved in processing IL-1β. Procaspase 8 (Choice C) and Caspase 8 (Choice D) are part of the extrinsic apoptosis pathway and are not directly involved in the processing of IL-1β. Therefore, the correct choice is Caspase 1 as it specifically cleaves pro-IL-1β to its active form.
Severe combined immunodeficiency (SCID) is a disease caused by:
- A. Infection with human immunodeficiency virus
- B. One of several inherited genetic mutations
- C. Deficiency of both innate and adaptive immune components
- D. Deficiency of hematopoietic stem cells
Correct Answer: B
Rationale: Step 1: SCID is a genetic disorder affecting the immune system.
Step 2: Inherited genetic mutations cause abnormalities in immune cells.
Step 3: These mutations lead to severe deficiencies in immune function.
Step 4: Choice B accurately reflects the genetic basis of SCID.
Summary: Choice A is incorrect because SCID is not caused by HIV. Choice C is incorrect as it oversimplifies the immune deficiencies in SCID. Choice D is incorrect because SCID primarily affects immune cells, not stem cells.
The inflammatory response produced
- A. by microbial-infected cells
- B. Internal tissue injury
- C. migration of erythrocyts from the spleen
- D. All above
Correct Answer: D
Rationale: The correct answer is D. The inflammatory response can be triggered by microbial-infected cells releasing cytokines, internal tissue injury leading to the release of inflammatory mediators, and the migration of erythrocytes from the spleen in response to inflammation. Therefore, all of the choices - A, B, and C - are correct in contributing to the inflammatory response. Each option plays a role in the complex cascade of events that lead to inflammation.
The epitopes recognized by T cells are always:
- A. Conformational
- B. Linear
- C. On the antigen surface
- D. Buried inside the antigen
Correct Answer: B
Rationale: The correct answer is B: Linear. T cells recognize linear epitopes, which are sequences of amino acids displayed in a linear fashion on the antigen's surface. This recognition occurs through the T cell receptor binding to the linear epitope. Conformational epitopes (A) involve multiple amino acid residues brought together in a specific three-dimensional structure. Epitopes on the antigen surface (C) are correct, but not all T cell epitopes are necessarily on the surface. Epitopes buried inside the antigen (D) are not accessible to T cell receptors for recognition. Thus, the correct choice is B due to the linear presentation of epitopes for T cell recognition.