This set of Class 12 Biology Chapter 8 Multiple Choice Questions & Answers (MCQs) focuses on “Human Health and Disease – Allergies”.
1. Anaphylactic shock is _______
a) Mild local reaction to an allergen
b) Severe local reaction
c) The severe reaction of the whole body
d) The mild reaction of the whole body
Explanation: Anaphylactic shock is a severe reaction to the whole body. It is a hypersensitive reaction of the body to a foreign substance like a bee sting, penicillin, serum protein, etc.
2. Hypersensitivity to an allergen is due to _________
a) Food Habits
b) Life style
c) Improper functioning of the immune system
Explanation: Hypersensitivity to an allergen is due to improper functioning of the immune system. Any result in the system results in discomfort, disease or even death of the organism.
3. The inflammatory response in allergy is due to the release of ________ by mast cells.
Explanation: Inflammatory response in allergy is due to the release of histamine by mast cells. Histamine along with IgE antibodies act as allergy mediator. It dilates arteries and causes fluid accumulation which causes the inflammatory response.
4. Allergy is an infectious disease which usually spreads by touching infected patients.
Explanation: Allergy is a non-infectious unusual reaction or hypersensitivity of an individual to a foreign substance or agent that is harmless to other individuals.
5. Which of the following usually cannot act as an allergen?
a) Pure Water
Explanation: Pure water usually cannot act an allergen to an individual because it is free of impurities. Allergen is any foreign substance or agent that produces hypersensitivity in an individual. For example, pollen, spores, dust, scent, wool, drugs like penicillin, egg white, fur, feathers, shellfish, etc.
6. What is meant by sensitisation of allergen?
a) When an allergen leaves the body
b) The first contact of an allergen
c) The incubation period of an allergen
d) When symptoms of the disease appear
Explanation: The allergen on first contact functions as a mild antigen. This process is called sensitisation. It produces antibodies which remain attached to the mast cells. These mast cells then release histamine and cause inflammatory responses in the body.
7. Which of the following is not a common manifestation of allergy?
a) Watering of Eyes
Explanation: Sneezing, Watering of Eyes, Oedema, Breathlessness, Coughing are some of the most common manifestations of allergy. Dust and mites are responsible for 40% of cases of allergy.
8. Which of the following diseases is an allergic response?
b) Hay Fever
c) Yellow Fever
Explanation: Hay Fever is an allergic swelling and secretion of the mucous membrane of nose, throat and conjunctiva in response to pollen and spores. Itchy and watery eyes, sneezing and running nose are its most common symptoms.
9. Which of the following allergies is characterised by circumscribed raised pinkish blisters?
a) Hay Fever
Explanation: Urticaria is an allergic response characterised by multiple, circumscribed raised pinkish, itchy blisters persisting for a few days. They can be caused due to a reaction of any food, medicine or any other allergens.
10. Eczema appears to run in families who have a personal history of allergic reactions.
Explanation: Eczema is a form of dermatitis which starts with reddening of the skin, the formation of vesicles and forming of scales. It appears to run in families who have a personal history of allergic reactions.
11. Allergic reactions are countered by the administration of _________
Explanation: Allergic reactions are countered by the administration of antihistamine, adrenaline and steroids that quickly reduce the symptoms of allergy. For determining the cause of the allergy, the patient is exposed to or injected with a very small dose of possible allergen and after that, the reactions on the body are studied.
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