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Practice Class 8 Science Chapter 2 Microorganisms: Friend and Foe MCQ Questions with Answers and Useful Details based on the NCERT syllabus. Revise antibiotics, vaccines, disease prevention, communicable diseases, and the safe use of medicines.
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Chapter Information
Subject: Science
Class: 8
Chapter: Microorganisms: Friend and Foe
Question Type: Multiple Choice Questions (MCQs)
Practice Set: 5
Difficulty Level: Moderate
Based On: NCERT Syllabus
Introduction
Microorganisms can be both beneficial and harmful. Some microorganisms are used to prepare food and medicines, while others cause diseases in humans, animals, and plants.
The discovery of antibiotics and the development of vaccines have played an important role in protecting people from many infectious diseases. However, antibiotics must be used carefully and only when appropriate.
Vaccination helps the body develop protection against particular diseases. Good hygiene, sanitation, safe food and water, and vaccination together play an important role in disease prevention.
This Practice Set 5 focuses on antibiotics, vaccines, disease prevention, and responsible use of medicines.
What You Will Learn
✔ Antibiotics
✔ Penicillin
✔ Alexander Fleming
✔ Uses of antibiotics
✔ Antibiotic resistance
✔ Vaccines
✔ Disease prevention
✔ Immunity
✔ Communicable diseases
✔ Safe use of medicines
Why This Topic Is Important
Infectious diseases have affected human populations throughout history. Scientific discoveries have provided effective methods for preventing and treating many diseases.
Antibiotics can be used against certain bacterial infections, while vaccines help protect people from specific infectious diseases.
Understanding the difference between antibiotics and vaccines is important because they work in different ways and are used for different purposes.
5 MCQs with Answers and Useful Details
Q1. Who discovered the antibiotic penicillin?
A) Alexander Fleming
B) Louis Pasteur
C) Robert Hooke
D) Isaac Newton
Answer:
A) Alexander Fleming
Useful Detail
Alexander Fleming discovered the antibiotic substance penicillin in 1928.
Penicillin was obtained from a type of fungus belonging to the genus Penicillium. Its discovery became an important milestone in the treatment of bacterial infections.
The discovery demonstrated that substances produced by microorganisms could be useful in controlling other microorganisms.
Correct Answer: A) Alexander Fleming
Q2. Which statement correctly describes an antibiotic?
A) It is always effective against viruses.
B) It is a medicine used to control or kill certain disease-causing microorganisms, especially bacteria.
C) It is a type of vaccine.
D) It is a nutrient required by plants.
Answer:
B) It is a medicine used to control or kill certain disease-causing microorganisms, especially bacteria.
Useful Detail
Antibiotics are medicines used to treat certain bacterial infections.
They are not generally effective against viral infections such as the common cold or influenza.
Unnecessary or incorrect use of antibiotics can contribute to antibiotic resistance, making some bacteria harder to control.
Therefore, antibiotics should be used only as advised by a qualified medical professional.
Correct Answer: B) It is a medicine used to control or kill certain disease-causing microorganisms, especially bacteria.
Q3. What is the main purpose of vaccination?
A) To increase food spoilage
B) To help the body develop protection against a particular disease
C) To replace all antibiotics
D) To increase the growth of harmful microorganisms
Answer:
B) To help the body develop protection against a particular disease
Useful Detail
A vaccine prepares the immune system to recognise and respond more effectively to a particular infectious disease.
Vaccination helps reduce the risk of developing certain diseases and can also help reduce their spread in populations.
Vaccines are different from antibiotics. Antibiotics are medicines used to treat certain bacterial infections, whereas vaccines are mainly used to prevent specific infectious diseases.
Correct Answer: B) To help the body develop protection against a particular disease
Q4. Which of the following is an important way to prevent the spread of communicable diseases?
A) Drinking contaminated water
B) Maintaining proper hygiene and sanitation
C) Sharing personal items with infected people
D) Leaving food uncovered
Answer:
B) Maintaining proper hygiene and sanitation
Useful Detail
Good hygiene and sanitation help reduce the spread of many infectious diseases.
Important measures include washing hands, drinking safe water, keeping surroundings clean, properly disposing of waste, and maintaining food hygiene.
Depending on the disease, vaccination, mosquito control, and avoiding close contact with infected individuals may also be important preventive measures.
Correct Answer: B) Maintaining proper hygiene and sanitation
Q5. Why should antibiotics not be taken unnecessarily?
A) They always cause immediate disease.
B) Unnecessary use can contribute to antibiotic resistance.
C) They increase the number of viruses.
D) They make food spoil faster.
Answer:
B) Unnecessary use can contribute to antibiotic resistance.
Useful Detail
When antibiotics are used unnecessarily or incorrectly, bacteria can develop resistance to them over time.
Antibiotic resistance means that certain bacteria are no longer effectively controlled by medicines that previously worked against them.
This makes some infections more difficult to treat.
Therefore, antibiotics should be used only when prescribed or advised by an appropriate healthcare professional.
Correct Answer: B) Unnecessary use can contribute to antibiotic resistance.
Important Formulas & Concepts
Science Chapter 2 does not contain mathematical formulas. Important scientific concepts are given below.
1. Antibiotics
Antibiotics are medicines used to control or kill certain disease-causing microorganisms, especially bacteria.
2. Penicillin
Penicillin is an important antibiotic discovered by Alexander Fleming.
3. Alexander Fleming
Alexander Fleming discovered penicillin in 1928.
4. Vaccines
Vaccines stimulate the immune system to develop protection against specific infectious diseases.
5. Immunity
Immunity refers to the body’s ability to defend itself against particular infections and disease-causing organisms.
6. Antibiotic Resistance
Antibiotic resistance occurs when bacteria become less sensitive or resistant to antibiotics, making infections harder to treat.
7. Disease Prevention
Disease prevention includes hygiene, sanitation, safe food and water, vaccination, and other measures appropriate to the disease.
8. Communicable Diseases
Communicable diseases can spread from infected individuals or other sources to healthy people.
9. Safe Use of Medicines
Medicines, especially antibiotics, should be taken according to professional medical advice.
10. Public Health
Vaccination, sanitation, clean water, hygiene, and disease surveillance all contribute to protecting community health.
Related Practice Questions
Q1. Who discovered penicillin?
Q2. What are antibiotics?
Q3. Why are antibiotics not effective against viral infections?
Q4. What is the purpose of vaccination?
Q5. What is antibiotic resistance?
Mini Quiz Challenge
Try answering these questions within 60 seconds.
Q1. Penicillin was discovered by:
A) Alexander Fleming
B) Newton
C) Darwin
D) Mendel
Q2. Antibiotics are mainly used to treat:
A) Certain bacterial infections
B) All viral diseases
C) Vitamin deficiencies
D) Broken bones
Q3. Vaccination mainly helps:
A) Prevent specific infectious diseases
B) Increase food spoilage
C) Produce antibiotics in food
D) Remove all microorganisms from the environment
Q4. Which practice helps prevent many infectious diseases?
A) Poor sanitation
B) Safe water and hygiene
C) Sharing used needles
D) Eating uncovered food
Q5. Unnecessary antibiotic use can contribute to:
A) Antibiotic resistance
B) Better digestion
C) Increased immunity to every disease
D) Food preservation
Exam Tips
✔ Remember Alexander Fleming and penicillin.
✔ Learn that antibiotics are mainly used against bacterial infections.
✔ Do not write that antibiotics cure viral diseases.
✔ Understand the purpose of vaccination.
✔ Learn the difference between prevention and treatment.
✔ Remember that unnecessary antibiotic use can contribute to resistance.
✔ Revise the role of hygiene and sanitation in disease prevention.
✔ Understand that vaccines are specific to particular diseases.
✔ Do not confuse vaccines with antibiotics.
✔ Use scientific terms carefully in MCQs and short-answer questions.
Quick Revision Notes
✔ Antibiotics: Medicines used to control or kill certain bacteria.
✔ Penicillin: An important antibiotic discovered by Alexander Fleming.
✔ Alexander Fleming: Discovered penicillin in 1928.
✔ Vaccines: Help the immune system develop protection against specific diseases.
✔ Immunity: Ability of the body to defend itself against particular infections.
✔ Antibiotic Resistance: Reduced effectiveness of antibiotics against resistant bacteria.
✔ Hygiene: Clean practices that help prevent disease transmission.
✔ Sanitation: Measures that maintain clean and safe surroundings.
✔ Safe Water: Helps reduce diseases transmitted through contaminated water.
✔ Disease Prevention: Includes vaccination, hygiene, sanitation, and other appropriate protective measures.
Common Mistakes Students Make
❌ Thinking antibiotics can cure the common cold.
❌ Confusing vaccines with antibiotics.
❌ Thinking vaccination is a treatment for every existing infection.
❌ Forgetting the name of the scientist who discovered penicillin.
❌ Thinking all bacteria are harmful.
❌ Assuming antibiotic resistance means a person’s body becomes resistant to antibiotics.
❌ Thinking antibiotics should be taken for every fever.
❌ Forgetting the importance of hygiene and sanitation.
Key Takeaways
✔ Alexander Fleming discovered penicillin.
✔ Penicillin is an important antibiotic.
✔ Antibiotics are mainly used against bacterial infections.
✔ Antibiotics are not generally effective against viral infections.
✔ Vaccines help protect against specific infectious diseases.
✔ Hygiene and sanitation help prevent many communicable diseases.
✔ Improper antibiotic use can contribute to antibiotic resistance.
✔ Responsible use of medicines is important for individual and public health.
FAQs
Q. Who discovered penicillin?
Answer:
Alexander Fleming discovered penicillin in 1928.
Q. What are antibiotics?
Answer:
Antibiotics are medicines used to control or kill certain disease-causing microorganisms, especially bacteria.
Q. Can antibiotics cure the common cold?
Answer:
Generally, no. The common cold is usually caused by viruses, and antibiotics do not work against viruses.
Q. What is vaccination?
Answer:
Vaccination is a method of stimulating the immune system to develop protection against a specific infectious disease.
Q. What is antibiotic resistance?
Answer:
Antibiotic resistance occurs when bacteria become resistant to medicines that were previously effective against them, making some infections harder to treat.
Conclusion
Class 8 Science Chapter 2 – Microorganisms: Friend and Foe focuses on antibiotics, vaccines, disease prevention, and the responsible use of medicines.
Students revised the discovery of penicillin by Alexander Fleming, the role of antibiotics in treating certain bacterial infections, the purpose of vaccination, and the importance of hygiene and sanitation.
The concept of antibiotic resistance is also important because improper use of antibiotics can make some bacterial infections more difficult to treat.
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