CBSE Class 8 > Class 8 Notes > Science > PPT: Microorganisms: Friend or Foe
PPT: Microorganisms: Friend or Foe
| Download, print and study this document offline |
Please wait while the PDF view is loading
Page 1 WHAT ARE MICROORGANISMS? Class-8 Page 2 WHAT ARE MICROORGANISMS? Class-8 What are Microorganisms? Microorganisms are tiny organisms that are too small to be seen with the naked eye. They include bacteria, fungi, protozoa, some algae, and viruses. Page 3 WHAT ARE MICROORGANISMS? Class-8 What are Microorganisms? Microorganisms are tiny organisms that are too small to be seen with the naked eye. They include bacteria, fungi, protozoa, some algae, and viruses. Microorganisms can survive in various environments, from extreme cold to hot springs. They may live independently or in colonies, and some can reside inside other organisms. Where do Microorganisms Live? Page 4 WHAT ARE MICROORGANISMS? Class-8 What are Microorganisms? Microorganisms are tiny organisms that are too small to be seen with the naked eye. They include bacteria, fungi, protozoa, some algae, and viruses. Microorganisms can survive in various environments, from extreme cold to hot springs. They may live independently or in colonies, and some can reside inside other organisms. Where do Microorganisms Live? Microorganisms play vital roles in our lives. They have beneficial uses in food production (e.g., curd, bread), alcohol fermentation, waste decomposition, and medicine (e.g., antibiotics). Microorganisms can enhance soil fertility through nitrogen fixation by certain bacteria. Microorganisms and Us Bacteria Virus Page 5 WHAT ARE MICROORGANISMS? Class-8 What are Microorganisms? Microorganisms are tiny organisms that are too small to be seen with the naked eye. They include bacteria, fungi, protozoa, some algae, and viruses. Microorganisms can survive in various environments, from extreme cold to hot springs. They may live independently or in colonies, and some can reside inside other organisms. Where do Microorganisms Live? Microorganisms play vital roles in our lives. They have beneficial uses in food production (e.g., curd, bread), alcohol fermentation, waste decomposition, and medicine (e.g., antibiotics). Microorganisms can enhance soil fertility through nitrogen fixation by certain bacteria. Microorganisms and Us Bacteria Virus Beneficial microbes aid in digestion, boost the immune system, and contribute to nutrient absorption. They are used in various food production processes, fermentation, and medicine. Microorganisms are used for large-scale production of alcohol, wine, and acetic acid. Yeast is commonly employed in alcohol and wine production. 1.Friendly Microorganisms: 2.Commercial Uses of Microorganisms: Microorganisms and Us Production of alcohol with the help of yeastRead More
FAQs on PPT: Microorganisms: Friend or Foe
| 1. What are beneficial microorganisms and how do they help us in everyday life? |  |
Ans. Beneficial microorganisms are bacteria, fungi, and protozoa that provide advantages to humans, animals, and plants. Lactobacillus in yoghurt aids digestion, fungi produce antibiotics like penicillin, and nitrogen-fixing bacteria enrich soil for crop growth. Yeast ferments bread and beverages. These microbes are essential allies in food production, medicine, and agriculture, making them friends rather than foes in our ecosystem.
| 2. How do harmful microorganisms cause diseases and what infections do they create? | |
Ans. Pathogenic microorganisms release toxins and invade body tissues, causing infectious diseases. Bacteria cause tuberculosis and cholera; viruses trigger influenza and chickenpox; fungi create skin infections like ringworm; protozoa lead to malaria and dysentery. These disease-causing microbes spread through contaminated food, water, air, or direct contact. Understanding how pathogens function helps students recognise transmission routes and prevention strategies effectively.
| 3. Why do some microorganisms spoil food and how can we prevent food spoilage? | |
Ans. Food-spoiling microorganisms break down nutrients through decomposition, producing unpleasant odours and toxins, making food unsafe. Bacteria and moulds multiply rapidly in favourable conditions. Prevention involves refrigeration (slowing microbial growth), pasteurisation (heat treatment), salting, pickling, and airtight storage. Fermentation by beneficial microbes like lactobacilli actually preserves food while adding nutritional value simultaneously.
| 4. What is the difference between aerobic and anaerobic microorganisms in the human body? | |
Ans. Aerobic microorganisms require oxygen for survival and respiration, thriving in well-oxygenated environments. Anaerobic microbes function without oxygen, inhabiting deep tissues and intestines. Most disease-causing bacteria are facultative anaerobes, surviving both conditions. Understanding microbial oxygen requirements helps explain why certain infections develop in specific body locations and influences antibiotic effectiveness against different pathogens.
| 5. How do antibiotics work against harmful bacteria and why is antibiotic resistance becoming dangerous? | |
Ans. Antibiotics kill or inhibit harmful bacteria by disrupting cell walls, protein synthesis, or DNA replication. However, repeated antibiotic overuse allows resistant bacteria to survive and multiply, creating superbugs immune to common treatments. This antibiotic resistance makes infections harder to treat and spreads through populations. Responsible antibiotic use and completing full courses prevent resistance development, protecting public health.
About this Document
45K Views
4.61/5 Rating
Apr 18, 2026 Last updated
Related Exams
Document Description: PPT: Microorganisms: Friend or Foe for Class 8 2026 is part of Science Class 8 preparation. The notes and questions for PPT: Microorganisms: Friend or Foe have been prepared according to the Class 8 exam syllabus. Information about PPT: Microorganisms: Friend or Foe covers topics like and PPT: Microorganisms: Friend or Foe Example, for Class 8 2026 Exam. Find important definitions, questions, notes, meanings, examples, exercises and tests below for PPT: Microorganisms: Friend or Foe.
Introduction of PPT: Microorganisms: Friend or Foe in English is available as part of our Science Class 8 for Class 8 & PPT: Microorganisms: Friend or Foe in Hindi for Science Class 8 course. Download more important topics related with notes, lectures and mock test series for Class 8 Exam by signing up for free. Class 8: PPT: Microorganisms: Friend or Foe
Description
PPT: Microorganisms: Friend or Foe of Science Class 8 - covers important aspects of the topic & is important for the Class 8 exam. Download the presentation on EduRev.
Information about PPT: Microorganisms: Friend or Foe
In this doc you can find the meaning of PPT: Microorganisms: Friend or Foe defined & explained in the simplest way possible. Besides explaining types of PPT: Microorganisms: Friend or Foe theory, EduRev gives you an ample number of questions to practice PPT: Microorganisms: Friend or Foe tests, examples and also practice Class 8 tests
Related Searches
PPT: Microorganisms: Friend or Foe, Extra Questions, Sample Paper, shortcuts and tricks, MCQs, study material, practice quizzes, Important questions, pdf , Previous Year Questions with Solutions, Free, Exam, ppt, Viva Questions, PPT: Microorganisms: Friend or Foe, past year papers, PPT: Microorganisms: Friend or Foe, Summary, mock tests for examination, Semester Notes, Objective type Questions, video lectures;