Very Short Answer Questions (50)

1. 1. Define disease.
   A condition in which the normal structure or function of any part of the body is disturbed, producing signs or symptoms.
2. 2. What is an infectious disease?
   A disease caused by pathogens that can spread from an infected person (or source) to a healthy person.
3. 3. Give one example of a non-infectious disease.
   Diabetes (a lifestyle-related, non-infectious disease).
4. 4. Name two types of pathogens.
   Bacteria and viruses (also fungi, protozoa, and helminths).
5. 5. What is a bacterium?
   A unicellular, prokaryotic microorganism without a membrane-bound nucleus.
6. 6. Give one disease caused by bacteria.
   Tuberculosis (caused by Mycobacterium tuberculosis).
7. 7. What are viruses?
   Acellular infectious particles made of nucleic acid (DNA or RNA) surrounded by a protein coat; they require host cells to reproduce.
8. 8. Give one disease caused by a virus.
   Influenza (flu) is caused by influenza viruses.
9. 9. What is a fungal infection example?
   Ringworm (a skin infection caused by fungi).
10. 10. Name a disease caused by protozoa.
    Malaria (caused by Plasmodium species).
11. 11. What is a helminth?
    A parasitic worm, such as tapeworms or roundworms, that may infect humans.
12. 12. How can infectious diseases spread via water and food?
    By ingesting contaminated food or water containing pathogenic microbes, e.g., cholera from contaminated water.
13. 13. What does 'airborne transmission' mean?
    Spread of pathogens through droplets expelled when an infected person coughs or sneezes, which others may inhale.
14. 14. Define 'vector' in disease transmission.
    A living organism (like mosquitoes) that carries and transmits a pathogen between hosts.
15. 15. Give an example of a vector-borne disease.
    Dengue, transmitted by Aedes mosquitoes.
16. 16. What is meant by 'direct contact' transmission?
    Transmission through physical contact with an infected person, e.g., touching, kissing.
17. 17. Define 'symptom'.
    A symptom is a subjective indication of disease experienced by the patient, like pain or fatigue.
18. 18. Define 'sign' in medical terms.
    An objective, observable feature of disease measured by others, e.g., fever, rash, or swelling.
19. 19. What is diagnosis?
    The process of identifying a disease using history, signs, symptoms and laboratory tests.
20. 20. Name one diagnostic test for tuberculosis.
    Sputum test for acid-fast bacilli or chest X-ray.
21. 21. What is immunity?
    The body's ability to resist or fight infections caused by pathogens.
22. 22. Name the two main types of immunity.
    Innate (non-specific) immunity and adaptive (specific) immunity.
23. 23. Give one example of a physical barrier in innate immunity.
    The skin acts as a physical barrier preventing pathogen entry.
24. 24. What are phagocytes?
    White blood cells (like macrophages) that engulf and digest pathogens.
25. 25. What is an antibody?
    A protein produced by B-lymphocytes that recognises and neutralises specific antigens.
26. 26. What is vaccination?
    Administration of a prepared antigen to stimulate immune memory and provide protection against a disease.
27. 27. What type of immunity does vaccination provide?
    Active immunity (the body produces its own antibodies and memory cells).
28. 28. What is herd immunity?
    Protection of a population when a large proportion is immune, reducing spread and protecting susceptible individuals.
29. 29. Why don't antibiotics work on viruses?
    Antibiotics target bacterial structures or processes; viruses lack these and replicate inside host cells, so antibiotics are ineffective.
30. 30. What is antibiotic resistance?
    When bacteria evolve mechanisms to survive exposure to antibiotics, making drugs less effective.
31. 31. Give one practical step to prevent foodborne diseases.
    Cook food thoroughly and store it safely to avoid contamination.
32. 32. How does handwashing help prevent disease?
    It removes pathogens from hands, reducing the chance of transmission via touch or food handling.
33. 33. What is sanitation?
    Practices and infrastructure for safe disposal of waste and maintaining clean environments to prevent disease.
34. 34. Name a waterborne disease.
    Cholera is a waterborne disease caused by contaminated water.
35. 35. What is a carrier?
    An individual who harbours a pathogen but may not show symptoms and can transmit it to others.
36. 36. What is an epidemic?
    A sudden increase in the number of cases of a disease above the expected level in a community or region.
37. 37. What is a pandemic?
    An epidemic that spreads over multiple countries or continents affecting a large number of people.
38. 38. Why is vector control important?
    Because controlling vectors like mosquitoes reduces transmission of vector-borne diseases such as malaria and dengue.
39. 39. Mention one role of public health in disease control.
    Organising vaccination programmes to prevent outbreaks and protect communities.
40. 40. Give one sign of cholera.
    Severe watery diarrhoea leading to dehydration.
41. 41. What is symptomatic treatment?
    Treatment aimed at relieving symptoms rather than curing the underlying cause, e.g., fever reducers for flu.
42. 42. What is passive immunity?
    Temporary immunity gained by receiving preformed antibodies (e.g., maternal antibodies in newborns).
43. 43. Give an example of passive immunity.
    Newborn babies receive antibodies from the mother through the placenta and breast milk.
44. 44. What is disinfectant?
    A chemical agent used to kill or inactivate pathogens on surfaces (e.g., bleach solutions).
45. 45. How is tuberculosis commonly treated?
    With a multi-drug antibiotic regimen prescribed for several months under supervision.
46. 46. What simple habit reduces respiratory infection spread in schools?
    Covering mouth and nose while coughing or sneezing and using tissues or elbow to reduce droplet spread.
47. 47. What is the role of vaccination in eradication of disease?
    Vaccination can eliminate diseases by interrupting transmission when coverage is high (e.g., smallpox eradication).
48. 48. Why should antibiotics be completed as prescribed?
    Completing the course ensures all bacteria are killed and reduces the risk of resistance developing.
49. 49. Name one fungal disease of humans.
    Athlete's foot (tinea pedis).
50. 50. Suggest a one-line personal hygiene rule to prevent infections.
    Wash hands with soap and water before eating and after using the toilet.

Use these 50 VSA items for quick revision. They follow NCERT Class 9 — Chapter 14: Why Do We Fall Ill? and are ideal for CBSE exam preparation.