Lakhmir Singh Solutions for Class 8 Science Chapter 2 Microorganisms: Friends and Foe

Microorganisms are an essential part of our ecosystem, playing both beneficial and harmful roles. Lakhmir Singh Class 8 Science Chapter 2 microorganisms Solutions explains how these tiny organisms contribute to ecological balance, participating in cycles like the nitrogen, oxygen, and carbon cycles.

This chapter highlights how microbes can be helpful, such as in food production and medicine, while also discussing their harmful effects, including disease transmission. It provides a clear understanding of communicable diseases, their causes, and prevention.

Get expert-prepared solutions to all questions in Lakhmir Singh Class 8 Science Chapter 2 microorganisms and boost your learning with step-by-step explanations. Also, explore NCERT solutions for Class 8 Science to enhance your preparation.

Lakhmir Singh Solutions For Class 8 Science Chapter 2 Download PDF

Looking for Lakhmir Singh Science Class 8 Solutions for Chapter 2 – Microorganisms: Friends and Foe? Download the PDF to get step-by-step answers covering topics like agricultural practices, soil preparation, irrigation, and crop protection. 

This PDF solution follows the NCERT syllabus and helps students understand the scientific methods of farming in a simple way. Get the Class 8 Science Chapter 2 PDF now for easy learning and exam preparation.

Types of Questions That Appear in Exams

This chapter generally carries 6 to 8 marks in school-level Science exams under the CBSE curriculum. However, marks may vary slightly depending on the exam pattern of your school.

Very Short Answer Questions (1 mark)

• Example: Name any two diseases caused by bacteria.
• Identify helpful microorganisms used in food preparation.

Short Answer Type Questions (2–3 marks)

• Example: Write any two uses of microorganisms.
• How do microorganisms spoil food?

Long Answer Type Questions (4–5 marks)

• Example: Explain how microorganisms are both helpful and harmful with examples.

Also Check: Class 8 Science Microorganisms MCQs

Features of Infinity Learn Lakhmir Singh Solutions for Class 8 Science Chapter 2 

1. Comprehensive Explanation of Microorganisms
   The solutions provide a detailed understanding of microorganisms, their types, roles, and impact on the environment, helping students grasp key concepts easily.
2. Step-by-Step Solutions for Better Learning
   All answers are structured in a step-by-step manner, making it easier for students to understand and retain the information while improving their scientific knowledge.
3. Covers Both Beneficial and Harmful Effects
   This chapter explains how microorganisms act as both friends and foes, covering topics like their use in food production, medicine, and environmental balance, as well as their role in causing diseases.
4. Aligned with NCERT and CBSE Guidelines
   The solutions are NCERT-based and follow the CBSE syllabus, ensuring that students get accurate and exam-focused content for effective learning.
5. Easy-to-Understand Language with Diagrams
   The content is explained in simple words with well-labeled diagrams, helping students visualize and remember key concepts related to microbial activities.

How to Download Lakhmir Singh Solutions for Class 8 Science Chapter 2 – PDF for Free

Downloading the Lakhmir Singh Science Class 8 Solutions for Chapter 2 – Microorganisms: Friend and Foe PDF is simple and convenient. These PDF solutions provide well-explained answers following the NCERT syllabus, helping students grasp key concepts easily. Visit Infinity Learn educational platform, search for Class 8 Science Chapter 2 PDF, and download it for free access to expert solutions anytime.

Topics Covered in Lakhmir Singh Solutions for Class 8 Science Chapter 2 

This chapter explores the role of microorganisms in our daily lives. The key topics covered include:

1. Types of Microorganisms – Tiny living things including bacteria, fungi, protozoa, and viruses that can only be seen with microscopes.
2. Useful Microorganisms – Helpful microbes that make medicines, improve farm soil, and create foods like yogurt and cheese.
3. Harmful Microorganisms – Disease-causing microbes and their prevention.
4. Microorganisms and Environment – Role in nitrogen fixation, decomposition, and recycling.
5. Food Preservation and Vaccination – Methods to protect food and prevent infections.

Lakhmir Singh Textbook Solutions for Class 8 Science Chapter 2 Microorganisms

Very Short Answer Type Questions

Q1. What device is used to observe microorganisms?
Answer: Microorganisms are viewed using a microscope.

Q2. Which type of microorganisms are capable of reproducing only within the cells of living organisms?
Answer:
Viruses are unique microorganisms that can multiply only when they enter and hijack the living cells of a host. Outside a host body, they remain inactive and cannot carry out life processes on their own.

Q3. What are the primary categories of microorganisms?
Answer: The main types of microorganisms include bacteria, viruses, protozoa, some fungi, and algae.

Q4. List two human diseases caused by bacteria.
Answer: Cholera and typhoid are illnesses triggered by bacteria.

Q5. Name two viral diseases affecting humans.
Answer: Influenza and the common cold are both caused by viruses.

Q6. Mention two diseases in humans caused by protozoa.
Answer: Malaria and amoebic dysentery are due to protozoan infections.

Q7. State two fungal infections in humans.
Answer: Ringworm and athlete’s foot are examples of fungal diseases.

Q8. Which microbe is involved in curd production from milk?
Answer: The bacterium Lactobacillus helps convert milk into curd.

Q9. Which microorganism aids in large-scale alcohol manufacture?
Answer: Yeast is utilized in the mass production of alcohol.

Q10. Give names of two commonly used antibiotics.
Answer: Erythromycin and streptomycin are well-known antibiotics.

Q11. Can you name an antibiotic that was originally discovered from a fungus? Also, mention the name of the fungus.
Answer: Yes, the antibiotic penicillin was the first to be discovered and it comes from a mold called Penicillium. This groundbreaking discovery was made by Alexander Fleming in 1928, revolutionizing the treatment of bacterial infections.

Q12. What are four diseases that can be prevented by timely vaccination?
Answer: Vaccines play a crucial role in building immunity and preventing several serious diseases. Four such diseases that can be controlled or prevented through vaccination are:

1. Hepatitis B
2. Tuberculosis (TB)
3. Cholera
4. Smallpox

Regular immunization programs help protect individuals and communities from the spread of these infections.

Q13. Who developed the smallpox vaccine?
Answer: Edward Jenner introduced the smallpox vaccine in 1798.

Q14. Name the scientist who found penicillin.
Answer: Penicillin was discovered by Alexander Fleming in the year 1929.

Q15. What is one major role of blue-green algae?
Answer: Blue-green algae improve soil by fixing nitrogen from the air.

Q16. Name a biological nitrogen-fixing microorganism.
Answer: Blue-green algae serve as natural nitrogen fixers.

Q17. Name two insects that spread disease-causing microbes.
Answer: Mosquitoes and houseflies are common transmitters of disease.

Q18. List two diseases spread by houseflies.
Answer: Tuberculosis and cholera can be spread by houseflies.

Q19. Which insect transmits the malaria parasite?
Answer: The female Anopheles mosquito spreads malaria.

Q20. Which insect carries the virus responsible for dengue?
Answer: Dengue virus is transmitted by the female Aedes mosquito.

Q21. Who is responsible for spreading dengue: housefly or mosquito?
Answer: The female Aedes mosquito spreads dengue, not the housefly.

Q22. Name two diseases that are transmitted through mosquito bites.
Answer: Malaria and dengue are mosquito-borne diseases.

Q23. Which microorganism causes malaria?
Answer: Malaria is caused by the protozoan Plasmodium.

Q24. Name a disease transmitted through airborne microorganisms.
Answer: Airborne spread of tuberculosis occurs via infected droplets.

Q25. Give an example of a disease spread through insect bites.
Answer: Malaria spreads through bites from infected mosquitoes.

Q26. Mention a disease transmitted by contaminated food or water.
Answer: Cholera is caused by ingesting polluted food or water.

Q27. What microbes cause the following animal diseases?
(a) Foot and mouth disease
(b) Anthrax
Answer:
(a) Foot and mouth disease – Caused by a virus.
(b) Anthrax – Caused by a bacterium.

Q28. Name two food items preserved by sun-drying at home.
Answer: Spinach and fenugreek leaves are often sun-dried for preservation.

Q29. Which two foods are preserved using salt?
Answer: Salt is used to preserve fish and meat.

Q30. Which food products are preserved using sugar?
Answer: Jams and jellies are preserved by adding sugar.

Q31. Name two items usually preserved by freezing.
Answer: Freezing is commonly used to store meat and fish.

Q32. Which preservatives are added in jams and jellies?
Answer: Sodium benzoate and sodium metabisulphite are often used.

Q33. List preservatives used in making pickles from fruits and vegetables.
Answer: Oil, vinegar, and salt are used to preserve pickles.

Q34. Which foods can be preserved with oil or vinegar?
Answer: Meat and fish can be kept fresh using vinegar or oil.

Q35. Name two chemical food preservatives.
Answer: Sodium metabisulphite and sodium benzoate are commonly used.

Q36. Which microorganisms help in fixing nitrogen in the soil?
Answer: Nitrogen fixation is carried out by certain bacteria and blue-green algae.

Q37. Which plants convert atmospheric nitrogen into usable compounds?
Answer: Legume plants are capable of fixing atmospheric nitrogen.

Q38. Which microorganisms reside in legume roots to fix nitrogen?
Answer: Rhizobium bacteria inhabit root nodules of legumes and fix nitrogen.

Q39. Name two leguminous plants that help in nitrogen fixation.
Answer: Pea and bean plants fix atmospheric nitrogen with bacterial help.

Benefits of Using Lakhmir Singh Class 8 Science Chapter 2 – Microorganisms

Their are many benefits of using Lakhmir singh solutions for class 8 science. Some are listed below:

1. Concept Clarity – Simplified explanations help students understand friendly and harmful microorganisms.
2. Exam-Oriented – NCERT-based solutions ensure students are well-prepared for exams.
3. Easy Revision – Summarized key points make quick learning possible.
4. Step-by-Step Solutions – Detailed answers enhance conceptual understanding.
5. PDF Accessibility – The Class 8 Science Chapter 2 PDF is easy to download and access anytime for learning on the go.

These solutions are a valuable resource for Class 8 students aiming for better understanding and scoring high in exams!