Last Updated on April 17, 2024 by XAM CONTENT
Hello students, we are providing assertion reason questions for class 8 science. Assertion reason questions are the new question format that is introduced in CBSE board. The resources for assertion reason questions are very less. So, to help students we have created chapterwise assertion reason questions for class 8 science. In this article, you will find assertion reason questions for cbse class 8 science chapter 2 microorganisms: friend and foe.
| Chapter | Microorganisms: Friend and Foe |
| Type of Questions | Assertion Reason Questions |
| Nature of Questions | Competency Based Questions |
| Board | CBSE |
| Class | 8 |
| Subject | Science |
| Useful for | Class 8 Studying Students |
| Answers provided | Yes |
| Difficulty level | Mentioned |
| Important Link | Class 8 Science Chapterwise Assertion Reason |
Assertion Reason on Microorganisms – Friend and Foe
Questions:
Q.1. Assertion (A): Bacteria are harmful for curd.
Reason (R): Milk is converted into curd by Lactobacillus.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A)
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Difficulty Level: Medium
Ans. Option (d) is correct.
Explanation: Milk is turned into curd by adding bacteria called Lactobacillus. It is a chemical change. Curd is more nutritional than milk as it has more quantity of proteins and vitamins (vitamin B12).
Q.2. Assertion (A): The antibodies remain in the body after killing the invader.
Reason (R): To protect our body from the disease causing organisms.
(Medium)
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A)
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Difficulty Level: Medium
Ans. Option (a) is correct.
Explanation: When a disease carrying microbe enter into the body, body internal defensive mechanism produces substance called antibodies, these antibodies fights and kills the invaders and also remembers how to fight with that disease carrying microbe. The antibodies remain in the body for a long time and protects from the disease causing microbes.
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Topics from which assertion reason questions may be asked
- Knowing types of micro-organisms.
- Learning about various friendly micro-organisms.
- Knowing how microorganisms are helpful.
- Discussing medicinal uses of micro-organisms.
- Discussing harmful micro-organisms and the diseases they cause.
- Knowing various methods of preserving food.
- Learning the nitrogen cycle in nature.
We find a large number of living organisms around us. Some of them are so tiny that they cannot be seen with the naked eye. They are called micro-organisms. We need a magnifying glass or a microscope to observe them. This chapter deals with study on how these microorganisms are useful as well as harmful to us. So based on this, the above topic list is provided.
