Immunology Basics – Flashcards with
Explanations
Q1. What is immunity?
Answer: Immunity is the ability of the body to resist harmful microorganisms or toxins.
Explanation: It is achieved through defense mechanisms like physical barriers (skin, mucosa),
innate immune cells, and adaptive responses (antibodies, T-cells).
Q2. What are the types of immunity?
Answer: Innate immunity and Adaptive immunity.
Explanation: Innate is non-specific and present at birth, while adaptive develops after exposure to
pathogens and provides long-term protection (memory).
Q3. What is an antigen?
Answer: An antigen is a foreign substance that triggers an immune response.
Explanation: It can be a protein, polysaccharide, or toxin. Antigens are recognized by antibodies or
immune cells, leading to activation of defense mechanisms.
Q4. What are antibodies?
Answer: Antibodies are proteins produced by B-cells that specifically recognize antigens.
Explanation: They neutralize pathogens, activate complement system, and help in opsonization
(marking pathogens for destruction).
Q5. What are T-cells?
Answer: T-cells are lymphocytes that regulate immune responses and kill infected cells.
Explanation: Helper T-cells (CD4+) activate B-cells, while Cytotoxic T-cells (CD8+) directly destroy
infected or cancerous cells.
Q6. What is innate immunity?
Answer: Innate immunity is the body’s first line of defense, present at birth.
Explanation: It includes physical barriers, phagocytes, natural killer cells, and inflammatory
responses. It acts quickly but is non-specific.
Q7. What is adaptive immunity?
Answer: Adaptive immunity is acquired during life after exposure to pathogens.
Explanation: It is highly specific and develops memory, enabling stronger responses upon
re-exposure (basis of vaccination).
Q8. What is the role of B-cells?
Answer: B-cells produce antibodies against specific antigens.
Explanations
Q1. What is immunity?
Answer: Immunity is the ability of the body to resist harmful microorganisms or toxins.
Explanation: It is achieved through defense mechanisms like physical barriers (skin, mucosa),
innate immune cells, and adaptive responses (antibodies, T-cells).
Q2. What are the types of immunity?
Answer: Innate immunity and Adaptive immunity.
Explanation: Innate is non-specific and present at birth, while adaptive develops after exposure to
pathogens and provides long-term protection (memory).
Q3. What is an antigen?
Answer: An antigen is a foreign substance that triggers an immune response.
Explanation: It can be a protein, polysaccharide, or toxin. Antigens are recognized by antibodies or
immune cells, leading to activation of defense mechanisms.
Q4. What are antibodies?
Answer: Antibodies are proteins produced by B-cells that specifically recognize antigens.
Explanation: They neutralize pathogens, activate complement system, and help in opsonization
(marking pathogens for destruction).
Q5. What are T-cells?
Answer: T-cells are lymphocytes that regulate immune responses and kill infected cells.
Explanation: Helper T-cells (CD4+) activate B-cells, while Cytotoxic T-cells (CD8+) directly destroy
infected or cancerous cells.
Q6. What is innate immunity?
Answer: Innate immunity is the body’s first line of defense, present at birth.
Explanation: It includes physical barriers, phagocytes, natural killer cells, and inflammatory
responses. It acts quickly but is non-specific.
Q7. What is adaptive immunity?
Answer: Adaptive immunity is acquired during life after exposure to pathogens.
Explanation: It is highly specific and develops memory, enabling stronger responses upon
re-exposure (basis of vaccination).
Q8. What is the role of B-cells?
Answer: B-cells produce antibodies against specific antigens.
