Immunity — Set 2
Biology · रोग प्रतिरोधक क्षमता · Questions 11–20 of 50
Which of the following is a non-specific immune response characterized by heat, pain, and swelling?
Correct Answer: D. Inflammation
Inflammation is a localized tissue response to injury or infection. It helps to isolate the site of damage and recruit white blood cells to clear pathogens. The increased blood flow causes the characteristic warmth and redness.
Antigen-presenting cells (APCs) include which of the following?
Correct Answer: D. Macrophages
Macrophages engulf pathogens and display their fragments to T-cells. This process is essential for activating the adaptive immune system. Macrophages are found in almost all tissues throughout the body.
The Y-shaped proteins that bind specifically to antigens are called?
Correct Answer: A. Antibodies
Antibodies are also known as immunoglobulins and are produced by plasma cells. They have specific binding sites that fit onto unique parts of a pathogen. This binding flags the pathogen for destruction by other immune cells.
Which of the following is an example of an 'Immunodeficiency' disorder?
Correct Answer: C. AIDS
AIDS is caused by the HIV virus, which specifically targets and destroys T-helper cells. This leaves the body highly susceptible to opportunistic infections and certain cancers. Immunodeficiency means the immune system's ability to fight infectious disease is compromised.
What is the primary role of Cytotoxic T-cells?
Correct Answer: D. Killing infected or cancerous cells
Cytotoxic T-cells identify and destroy cells that have been compromised by viruses. They recognize specific antigens presented on the surface of these target cells. This cell-mediated response is vital for clearing intracellular infections.
Which substance in tears and saliva kills bacteria by breaking down their cell walls?
Correct Answer: D. Lysozyme
Lysozyme is an enzyme that acts as a natural antimicrobial agent. It is found in many body secretions to protect surfaces from infection. It specifically targets the peptidoglycan layer found in bacterial cell walls.
Passive immunity differs from active immunity because it?
Correct Answer: D. Does not involve the body's own cells
Passive immunity involves receiving antibodies produced by another individual or animal. Because the recipient's own B-cells are not activated, no memory cells are created. Consequently, the protection is immediate but only lasts for a few weeks or months.
Which of the following describes 'Vaccination'?
Correct Answer: A. Artificial Active Immunity
Vaccination introduces a harmless form of a pathogen to stimulate the immune system. The body produces its own antibodies and memory cells without actually getting the disease. This is a primary method for preventing widespread infectious diseases.
What happens to a pathogen during 'Phagocytosis'?
Correct Answer: D. It is engulfed and digested
Phagocytosis is the process where cells like neutrophils and macrophages 'eat' foreign particles. The pathogen is enclosed in a vesicle and broken down by powerful enzymes. This is a fundamental non-specific defense mechanism.
Which immunoglobulin (Ig) is most abundant in the human blood?
Correct Answer: B. IgG
IgG is the primary antibody involved in the secondary immune response. It is small enough to cross the placenta and provide immunity to the fetus. It represents about 75-80% of all antibodies in the circulation.