What disease is associated with autoantibodies binding to type IV collagen?
- A. Sarcoidosis
- B. Goodpasture's syndrome
- C. Systemic lupus erythematosus (SLE)
- D. Rheumatoid arthritis
Correct Answer: B
Rationale: The correct answer is B: Goodpasture's syndrome. This disease is specifically associated with autoantibodies targeting type IV collagen in the basement membranes of the kidneys and lungs, leading to glomerulonephritis and pulmonary hemorrhage. Sarcoidosis (A) involves non-caseating granulomas, not collagen autoantibodies. Systemic lupus erythematosus (SLE) (C) is associated with various autoantibodies but not specifically targeting type IV collagen. Rheumatoid arthritis (D) is characterized by autoantibodies against citrullinated peptides and synovial tissue, not type IV collagen.
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Which T cell type is involved in directly killing infected or foreign cells?
- A. Helper T cells
- B. Cytotoxic T cells
- C. Regulatory T cells
- D. Memory T cells
Correct Answer: B
Rationale: The correct answer is B: Cytotoxic T cells. Cytotoxic T cells are responsible for directly killing infected or foreign cells by releasing toxic substances that induce apoptosis in the target cells. This process helps eliminate the threats to the body.
Helper T cells (Choice A) assist in coordinating immune responses but do not directly kill cells. Regulatory T cells (Choice C) play a role in suppressing immune responses to prevent autoimmunity but do not kill infected cells. Memory T cells (Choice D) are primed for rapid response upon re-exposure to a specific antigen but do not directly kill cells. Therefore, the correct choice is B as cytotoxic T cells are specifically designed for cell killing.
In reference to the flow diagram below respond to the following question. The annotation A refers to which sites
- A. Annealing
- B. Melting
- C. Restriction
- D. RNAse
Correct Answer: C
Rationale: The correct answer is C: Restriction. In a flow diagram, the annotation "Restriction" likely indicates the site where a DNA molecule is being cut by a restriction enzyme. This process is essential in molecular biology for DNA manipulation.
Choice A: Annealing involves the process of complementary DNA strands coming together, usually during PCR or hybridization.
Choice B: Melting refers to the separation of double-stranded DNA into single strands, often seen in denaturation steps.
Choice D: RNAse is an enzyme that specifically degrades RNA molecules, not involved in the DNA manipulation processes indicated in the diagram.
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.
The researcher that postulated the existence of 'pattern recognition receptors' on innate cells was:
- A. Susumu Tonegawa
- B. Ilya Metchnikoff
- C. Charles Janeway
- D. Ralph Steinman
Correct Answer: C
Rationale: The correct answer is C: Charles Janeway. He proposed the existence of pattern recognition receptors on innate cells in the 1980s, leading to the development of the concept of innate immunity. Janeway's hypothesis revolutionized our understanding of immune responses by emphasizing the role of pattern recognition in detecting pathogens. Tonegawa is known for his work on immune diversity; Metchnikoff discovered phagocytes; and Steinman identified dendritic cells. Janeway's contribution to immunology specifically focuses on pattern recognition receptors, making him the correct choice for this question.
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.