Actual Questions and Answers
Expert-Verified Explanation
This Exam contains:
✪ 40 Questions and Answers
✪ Multiple-choice and True/False Format
✪ Expert-Verified Explanations
✪ Verified with Trusted Textbooks
1. What is the function of cathelicidins in human immunity?
A. Promote histamine production
B. Enhance leukocyte chemotaxis
C. Family of antimicrobial peptides; humans have one member
D. Inhibit cytokine expression
Answer: C
EXPLANATION: Cathelicidins are antimicrobial peptides that serve as a first line of defense
against infection. Humans possess only one member, LL-37, that disrupts microbial membranes.
2. What is the role of defensins in the immune system?
A. Stimulate T-cell proliferation
B. Inhibit microbial growth
C. Degrade histamine
D. Promote antibody production
Answer: B
EXPLANATION: Defensins are small cysteine-rich peptides that disrupt microbial membranes
and inhibit their growth, especially effective against bacteria, fungi, and some viruses.
3. Mannose-binding lectin (MBL) activates which pathway of the complement system?
A. Classical
B. Alternative
C. Lectin
D. Coagulation
Answer: C
EXPLANATION: MBL binds to mannose residues on pathogens and activates the complement
system via the lectin pathway, independent of antibodies.
, 4. Where is resistin-like molecule beta found and what is its function?
A. Liver; activates complement
B. Intestinal goblet cells; protects against helminths
C. Neurons; blocks inflammation
D. Kidney; regulates sodium
Answer: B
EXPLANATION: Resistin-like molecule beta is produced by intestinal goblet cells and helps
defend against parasitic infections, such as helminths.
5. What type of pathogens are antimicrobial lectins primarily active against?
A. Viruses
B. Gram-negative bacteria
C. Gram-positive bacteria
D. Fungi
Answer: C
EXPLANATION: Antimicrobial lectins, particularly C-type lectins, are carbohydrate-binding
proteins effective against Gram-positive bacteria.
6. What is the function of bactericidal/permeability-inducing protein (BPI)?
A. Degrades fibrin
B. Stimulates eosinophils
C. Reacts with lipopolysaccharide to lyse gram-negative bacteria
D. Activates the coagulation cascade
Answer: C
EXPLANATION: BPI, found in neutrophils and intestinal epithelium, binds to LPS on gram-
negative bacteria, leading to bacterial lysis.
7. The inflammatory response is considered part of which immunity?
A. Adaptive
B. Humoral
C. Nonspecific (innate)
D. Cell-mediated
Answer: C
EXPLANATION: Inflammation is a nonspecific immune response to tissue injury or infection,
part of innate immunity.
8. Which is NOT a step in the acute inflammatory response?
A. Vasodilation