Nokea
Which part of an antibody determines its antigen specificity?
- A. Fc fragment
- B. Fab region
- C. Heavy chain constant region
- D. Light chain constant region
Correct Answer: B
Rationale: The correct answer is B: Fab region. The Fab region of an antibody contains the antigen-binding site, where specific interactions with antigens occur. This region is formed by the variable regions of both the heavy and light chains. The Fc fragment (choice A) is responsible for effector functions, not antigen specificity. The heavy chain constant region (choice C) and light chain constant region (choice D) are not involved in antigen binding, but rather provide structural support and determine the antibody class. Therefore, the Fab region is crucial for antigen specificity due to its variable regions that directly interact with antigens.
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Which of the following correctly explains an epitope?
- A. Region of antibody that binds with antigen
- B. Region of antigen that elicit secretion of specific antibody
- C. Heavy chain of an antibody
- D. V-region of the light chain of antibody
Correct Answer: B
Rationale: Explanation:
An epitope is a specific region on an antigen that elicits the immune response and triggers the production of a specific antibody. Therefore, choice B is correct as it accurately defines an epitope. Choices A, C, and D are incorrect because they do not accurately describe what an epitope is. Choice A refers to the paratope, the region of the antibody that binds to the epitope. Choice C refers to a component of the antibody structure, and choice D refers to a specific region of the antibody structure.
The earliest event of an inflammatory response is
- A. Release of chemokines
- B. Recruitment of neutrophils
- C. Activation of adaptive immunity
- D. Activation of TLRs
Correct Answer: D
Rationale: The correct answer is D: Activation of TLRs. The earliest event in an inflammatory response is the activation of Toll-like receptors (TLRs) by recognizing pathogen-associated molecular patterns (PAMPs). This triggers a signaling cascade leading to the release of pro-inflammatory cytokines and chemokines, which then recruit neutrophils to the site of infection. Activation of adaptive immunity (choice C) occurs later in the immune response, as it involves the activation of T and B cells. While chemokines (choice A) are involved in recruiting immune cells, their release is a consequence of TLR activation. Neutrophils (choice B) are recruited after the release of chemokines.
What is the medical term for an abnormal accumulation of blood in a tissue or organ?
- A. Hematoma
- B. Thrombosis
- C. Embolus
- D. Hemorrhage
Correct Answer: A
Rationale: The correct answer is A: Hematoma. A hematoma is an abnormal collection of blood within tissues. This occurs due to broken blood vessels and can lead to swelling and localized pain. Thrombosis (B) is the formation of a blood clot within a blood vessel, not an accumulation of blood in tissue. An embolus (C) is a blood clot that travels through the bloodstream and gets lodged in a blood vessel. Hemorrhage (D) refers to the excessive bleeding from blood vessels. In this case, the most appropriate term for an abnormal accumulation of blood in a tissue is hematoma.
Which of the following statements is NOT true? The SARS coronavirus
- A. Caused an epidemic in 2003 that registered 10% mortality rate
- B. Caused an acute infection of the lungs classified as acute respiratory distress syndrome
- C. Is also the causal agent of MERS (Middle East Respiratory Syndrome)
- D. Is thought to have been transmitted from bats to civets and from civets to humans
Correct Answer: C
Rationale: The correct answer is C because the statement that SARS coronavirus is also the causal agent of MERS is false. MERS (Middle East Respiratory Syndrome) is caused by a different coronavirus called MERS-CoV. SARS-CoV caused the 2003 epidemic with a 10% mortality rate, which aligns with statement A. Statement B is correct as SARS-CoV does cause an acute infection of the lungs known as acute respiratory distress syndrome. Statement D is also true as SARS-CoV is believed to have been transmitted from bats to civets and then to humans. Therefore, the incorrect statement is C.
What is the primary function of white blood cells?
- A. Clotting and sealing damaged blood vessels
- B. Transporting oxygen and carbon dioxide
- C. Protecting the body from foreign substances
- D. Producing hormones
Correct Answer: C
Rationale: The primary function of white blood cells is to protect the body from foreign substances such as bacteria, viruses, and other pathogens. They do this by identifying and attacking these invaders to prevent infections and maintain overall health. White blood cells are a crucial part of the immune system and play a key role in defending the body against diseases. Clotting and sealing damaged blood vessels (choice A) is primarily done by platelets, not white blood cells. Transporting oxygen and carbon dioxide (choice B) is the function of red blood cells, not white blood cells. Producing hormones (choice D) is mainly performed by endocrine glands, not white blood cells.