📌 How to Use
First read the questions carefully using the Read section. Use the Details button to understand concepts clearly. After completing reading, click Practice Quiz to test yourself.
📘 Study MCQs
Q1. which microorganism is used to produce the antibiotic penicillin?
• bacteria
• virus
• fungus
• protozoa
Answer: fungus
the antibiotic penicillin is obtained from the fungus penicillium.
Q2. what is the main purpose of vaccination?
• to cure a disease
• to kill pathogens directly
• to provide temporary relief
• to develop immunity against a disease
Answer: to develop immunity against a disease
vaccines train our immune system to recognize and fight specific pathogens, providing long-term protection.
Q3. which bacteria are found in the root nodules of leguminous plants and help in increasing soil fertility?
• lactobacillus
• rhizobium
• streptococcus
• e. coli
Answer: rhizobium
rhizobium bacteria live in root nodules and convert atmospheric nitrogen into a usable form for plants, enriching the soil.
Q4. tuberculosis is caused by which type of microorganism?
• virus
• fungus
• bacteria
• protozoa
Answer: bacteria
tuberculosis (tb) is caused by the bacterium mycobacterium tuberculosis.
Q5. the disease chickenpox is primarily transmitted through which mode?
• contaminated water
• air and direct contact
• mosquito bite
• contaminated food
Answer: air and direct contact
the chickenpox virus spreads through airborne droplets from coughs or sneezes and direct contact with the rash.
Q6. what is the most effective general preventive measure against polio?
• using mosquito nets
• drinking boiled water
• vaccination
• eating cooked food
Answer: vaccination
the polio vaccine is highly effective in preventing the disease. it is given orally (opv) or as an injection (ipv).
Q7. hepatitis b primarily affects which organ of the human body?
• lungs
• heart
• liver
• kidney
Answer: liver
the hepatitis b virus causes infection and inflammation of the liver.
Q8. which of the following diseases is caused by a protozoan?
• typhoid
• cholera
• malaria
• measles
Answer: malaria
malaria is caused by a protozoan parasite of the genus plasmodium.
Q9. what is the common mode of transmission for cholera?
• air
• contaminated water and food
• direct contact
• mosquito bite
Answer: contaminated water and food
cholera spreads through water or food contaminated with the bacterium vibrio cholerae.
Q10. which vaccine is given to prevent tuberculosis?
• bcg vaccine
• opv (oral polio vaccine)
• mmr vaccine
• dtp vaccine
Answer: bcg vaccine
the bcg (bacille calmette-guérin) vaccine is used to provide immunity against tuberculosis.
Q11. what do we call medicines that kill or stop the growth of bacteria?
• antiseptics
• vaccines
• antibiotics
• antivirals
Answer: antibiotics
antibiotics are medicines that specifically target and inhibit bacterial infections.
Q12. what is the role of blue-green algae in soil?
• causes disease in plants
• adds color to soil
• fixes atmospheric nitrogen
• makes soil acidic
Answer: fixes atmospheric nitrogen
certain blue-green algae, like some bacteria, can convert atmospheric nitrogen into compounds that enrich the soil.
Q13. which disease is characterized by high fever, rash, and runny nose, and is caused by a virus?
• typhoid
• measles
• cholera
• tuberculosis
Answer: measles
measles is a highly contagious viral disease with symptoms like high fever, cough, runny nose, and a characteristic rash.
Q14. how can we primarily prevent the spread of typhoid?
• using mosquito nets
• consuming properly cooked food and boiled water
• avoiding crowded places
• taking antibiotics regularly
Answer: consuming properly cooked food and boiled water
typhoid is a water and food-borne disease caused by salmonella typhi. proper hygiene and safe water/food are key to prevention.
Q15. which microorganism is the causative agent for polio?
• bacteria
• fungus
• virus
• protozoa
Answer: virus
poliomyelitis (polio) is caused by the poliovirus.
Q16. what is a common symptom of cholera?
• severe watery diarrhea
• persistent dry cough
• skin rash
• joint pain
Answer: severe watery diarrhea
cholera infection leads to severe dehydration due to profuse, watery diarrhea.
Q17. the mmr vaccine protects against which set of diseases?
• malaria, measles, rabies
• measles, mumps, rubella
• mumps, malaria, rotavirus
• measles, meningitis, typhoid
Answer: measles, mumps, rubella
the mmr vaccine is a combined vaccine that provides protection against measles, mumps, and rubella.
Q18. which part of the plant forms a symbiotic relationship with nitrogen-fixing bacteria?
• leaves
• flowers
• stem
• root nodules
Answer: root nodules
bacteria like rhizobium live in the root nodules of plants like peas and beans, where they fix nitrogen.
Q19. what is the full form of opv, a vaccine related to one of these diseases?
• oral polio vaccine
• oral pertussis vaccine
• official polio virus
• oral pathogen vaccine
Answer: oral polio vaccine
opv stands for oral polio vaccine, which contains a weakened form of the poliovirus.
Q20. malaria is transmitted by the bite of which mosquito?
• female anopheles mosquito
• female aedes mosquito
• female culex mosquito
• male anopheles mosquito
Answer: female anopheles mosquito
the female anopheles mosquito acts as a vector, carrying the plasmodium parasite from an infected person to a healthy one.
Q21. which disease can be prevented by maintaining personal hygiene and good sanitary habits?
• polio
• cholera
• hepatitis b
• all of the above
Answer: all of the above
many diseases, including cholera and hepatitis b, can be prevented by good hygiene and sanitation, which stop the spread of germs.
Q22. what is the causative microorganism for hepatitis b?
• hepatitis b virus
• hepatitis b bacteria
• hepatitis b protozoa
• hepatitis b fungus
Answer: hepatitis b virus
hepatitis b is a viral infection caused by the hepatitis b virus (hbv).
Q23. which of these is a harmful role of microorganisms?
• making curd
• causing diseases
• making bread
• fixing nitrogen
Answer: causing diseases
some microorganisms are pathogens that cause various diseases in humans, animals, and plants.
Q24. what is the primary mode of transmission for tuberculosis?
• through air when an infected person coughs or sneezes
• through contaminated water
• through mosquito bites
• through physical touch only
Answer: through air when an infected person coughs or sneezes
tb bacteria are released into the air via droplets when a person with active tb coughs, sneezes, or speaks.
Q25. which of these is a bacterial disease?
• measles
• chicken pox
• tuberculosis
• polio
Answer: tuberculosis
tuberculosis is caused by bacteria, while measles, chicken pox, and polio are viral diseases.
Q26. what is a key preventive measure specifically against mosquito-borne diseases like malaria?
• drinking filtered water
• using mosquito nets and repellents
• eating freshly cooked food
• wearing warm clothes
Answer: using mosquito nets and repellents
preventing mosquito bites is the primary way to avoid malaria. this includes using nets, repellents, and preventing mosquito breeding.
Q27. which disease results in paralysis and is preventable by vaccination?
• cholera
• polio
• typhoid
• malaria
Answer: polio
polio can lead to irreversible paralysis. vaccination has been highly successful in controlling it globally.
Q28. what do we call a substance that contains a weakened or killed pathogen used to prevent disease?
• antibiotic
• antiseptic
• vaccine
• antibody
Answer: vaccine
a vaccine contains a weakened, killed, or part of a pathogen that stimulates the body’s immune system to develop immunity.
Q29. a child has a high fever and small red spots with blisters on the body. which disease is this likely to be?
• measles
• chicken pox
• typhoid
• tuberculosis
Answer: chicken pox
chicken pox is characterized by an itchy rash that turns into red spots and then fluid-filled blisters.
Q30. why is it important to finish the full course of antibiotics prescribed by a doctor?
• to please the doctor
• to ensure all bacteria are killed and prevent antibiotic resistance
• because antibiotics are expensive
• to build a habit
Answer: to ensure all bacteria are killed and prevent antibiotic resistance
stopping early can leave the strongest bacteria alive. these can multiply, causing a relapse and potentially becoming resistant to the antibiotic.
Q31. which of these diseases has no effective antibiotic treatment because it is caused by a virus?
• tuberculosis
• typhoid
• cholera
• common cold
Answer: common cold
antibiotics work only against bacteria. the common cold is caused by viruses, so antibiotics are ineffective against it.
Q32. what is the main benefit of crop rotation with leguminous plants?
• increases pest resistance
• improves soil fertility by adding nitrogen
• makes harvesting easier
• requires less water
Answer: improves soil fertility by adding nitrogen
leguminous plants host nitrogen-fixing bacteria in their roots, which add natural nitrogen fertilizers to the soil for the next crop.
Q33. which disease is prevented by the dtp vaccine?
• diphtheria, tetanus, polio
• diphtheria, typhoid, pertussis
• diphtheria, tetanus, pertussis (whooping cough)
• dengue, tuberculosis, pneumonia
Answer: diphtheria, tetanus, pertussis (whooping cough)
the dtp vaccine protects against three serious diseases: diphtheria, tetanus, and pertussis (whooping cough).
Q34. what is a common initial symptom of measles?
• watery diarrhea
• high fever with cough and runny nose
• severe headache and stiff neck
• painful joints
Answer: high fever with cough and runny nose
measles typically begins with a high fever, cough, runny nose, and red, watery eyes, followed by a rash.
Q35. how does boiling drinking water help in disease prevention?
• it adds minerals
• it improves taste
• it kills harmful microorganisms
• it cools the water
Answer: it kills harmful microorganisms
boiling water at a rolling boil for a few minutes kills disease-causing bacteria, viruses, and protozoa, making it safe to drink.
Q36. which organ is most severely affected by tuberculosis?
• liver
• lungs
• brain
• stomach
Answer: lungs
tuberculosis most commonly affects the lungs (pulmonary tb), causing a persistent cough, chest pain, and coughing up blood.
Q37. what is the name of the protozoan that causes malaria?
• entamoeba
• plasmodium
• giardia
• trypanosoma
Answer: plasmodium
malaria is caused by parasites of the genus plasmodium, with plasmodium falciparum being the most deadly.
Q38. vaccination is an example of which type of immunity?
• natural active immunity
• artificial active immunity
• natural passive immunity
• artificial passive immunity
Answer: artificial active immunity
vaccination introduces a safe form of the pathogen, prompting the body to produce its own antibodies, providing “artificial active immunity.”
Q39. which of these is a recommended practice to prevent the spread of chickenpox?
• sharing clothes with the patient
• keeping the patient in isolation
• allowing the patient to play outside
• not washing hands
Answer: keeping the patient in isolation
since chickenpox is highly contagious, keeping the infected person away from others, especially those not vaccinated, helps prevent its spread.
Q40. what is the main reason for adding a small amount of old curd to warm milk to make new curd?
• for taste
• old curd acts as a starter containing lactobacillus bacteria
• to change the color
• to make it cold
Answer: old curd acts as a starter containing lactobacillus bacteria
the old curd contains live lactobacillus cultures which ferment the lactose in warm milk, converting it into curd.
Q41. which of these is a viral disease that causes inflammation of the liver and can be prevented by vaccination?
• hepatitis b
• tuberculosis
• typhoid
• cholera
Answer: hepatitis b
hepatitis b is a viral infection that attacks the liver. a safe and effective vaccine is available to prevent it.
Q42. what is the primary source of most antibiotics?
• viruses
• bacteria and fungi
• synthetic chemicals only
• plants
Answer: bacteria and fungi
many antibiotics are derived from microorganisms themselves. for example, penicillin from fungus and streptomycin from bacteria.
Q43. spraying insecticides and not allowing water to collect helps control which disease?
• typhoid
• polio
• malaria
• cholera
Answer: malaria
these measures destroy mosquito breeding sites and kill adult mosquitoes, which are the vectors for the malaria parasite.
Q44. what is a common symptom of typhoid fever?
• skin rash
• prolonged high fever and weakness
• muscle cramps
• blurred vision
Answer: prolonged high fever and weakness
typhoid fever is characterized by a sustained high fever, headache, weakness, stomach pain, and sometimes a rash.
Q45. which microorganism is used in the production of vaccines?
• only viruses
• weakened or killed forms of pathogens (viruses/bacteria)
• only bacteria
• only protozoa
Answer: weakened or killed forms of pathogens (viruses/bacteria)
vaccines are made from weakened (attenuated), killed, or parts of the disease-causing virus or bacterium.
Q46. which practice helps in “biological nitrogen fixation”?
• adding chemical fertilizers
• growing leguminous plants
• adding compost
• ploughing the field
Answer: growing leguminous plants
leguminous plants have a symbiotic relationship with rhizobium bacteria in their root nodules, which fix atmospheric nitrogen biologically.
Q47. what is the full form of bcg in the bcg vaccine?
• bacille calmette-guérin
• bacterial cell germ
• body cell guard
• bacteria combatting germ
Answer: bacille calmette-guérin
bcg stands for bacille calmette-guérin, named after the french scientists who developed it.
Q48. which disease is also known as ‘lockjaw’?
• polio
• tetanus
• typhoid
• hepatitis
Answer: tetanus
tetanus, caused by clostridium tetani bacteria, often causes stiffness and locking of the jaw muscles, hence the name lockjaw.
Q49. why should a person with an infectious disease like tuberculosis be kept in isolation?
• to punish them
• to prevent the spread of the disease through air to others
• because they are dangerous
• to make them rest
Answer: to prevent the spread of the disease through air to others
isolation reduces the chance of the tb bacteria being released into the air and infecting other people.
Q50. oral rehydration solution (ors) is primarily used to treat dehydration caused by which type of disease?
• airborne diseases like tb
• water-borne diseases causing diarrhea like cholera
• mosquito-borne diseases like malaria
• deficiency diseases
Answer: water-borne diseases causing diarrhea like cholera
ors replaces lost fluids and electrolytes during severe diarrhea, a common symptom of water-borne diseases like cholera.
Q51. which of these is not a water-borne disease?
• cholera
• typhoid
• hepatitis b
• malaria
Answer: malaria
malaria is a vector-borne disease transmitted by mosquitoes, not directly through contaminated water.
Q52. what is the primary reason for the who-led global polio eradication initiative?
• polio has no treatment
• polio vaccine is very expensive
• polio can cause permanent paralysis and is preventable by vaccine
• polio only affects children
Answer: polio can cause permanent paralysis and is preventable by vaccine
polio can lead to lifelong paralysis but can be completely prevented with vaccination, making global eradication a feasible goal.
Q53. which microorganism is responsible for causing anthrax, a disease in cattle?
• virus
• bacteria
• fungus
• protozoa
Answer: bacteria
anthrax is a serious infectious disease caused by the bacterium bacillus anthracis, which can affect animals and humans.
Q54. what does a vaccine introduce into the body?
• strong antibiotics
• live, fully active pathogens
• weakened or dead pathogens or their parts
• white blood cells
Answer: weakened or dead pathogens or their parts
vaccines contain antigens from the pathogen that are too weak to cause illness but strong enough to stimulate an immune response.
Q55. which practice is part of maintaining good sanitary habits to prevent diseases?
• covering mouth while coughing/sneezing
• proper disposal of garbage
• using clean toilets
• all of the above
Answer: all of the above
all these practices help break the chain of infection by preventing the spread of germs into the environment.
Q56. which disease’s mode of transmission is specifically through the air?
• cholera
• tuberculosis
• hepatitis b
• typhoid
Answer: tuberculosis
tuberculosis is an airborne disease. the bacteria spread through tiny droplets released into the air via coughs or sneezes.
Q57. what is the main action of an antibiotic on a disease-causing bacterium?
• it provides nutrients to the body
• it kills or inhibits the growth of the bacterium
• it increases body temperature
• it produces antibodies
Answer: it kills or inhibits the growth of the bacterium
antibiotics work by interfering with processes essential for bacterial growth or survival, such as cell wall formation or protein synthesis.
Q58. the hepatitis b vaccine is usually given in how many doses?
• one dose
• two doses
• three doses
• four doses
Answer: three doses
the hepatitis b vaccine is typically administered as a series of three shots over a period of six months for full protection.
Q59. what is the primary cause of soil fertility depletion?
• growing too many plants
• continuous growing of the same crop without nutrient replenishment
• presence of earthworms
• too much sunlight
Answer: continuous growing of the same crop without nutrient replenishment
this practice uses up the same nutrients from the soil repeatedly. crop rotation, especially with nitrogen-fixing plants, helps restore fertility.
Q60. which of the following is a correct pair of disease and its preventive vaccine?
• malaria – bcg
• tuberculosis – opv
• polio – opv
• typhoid – mmr
Answer: polio – opv
opv is the oral polio vaccine used to prevent polio. bcg is for tb, mmr is for measles/mumps/rubella, and there is a separate vaccine for typhoid.