Microorganisms-Friends and Foe

Microorganisms friends and foe Worksheet-14

Answer the following Questions:

1. Describe the nitrogen cycle with the help of a nee and labelled diagram.

2. (a) How do microorganisms spoil food?

(b) What are the chemical methods of preserving food material from the attack of microorganisms?

Or

What are microorganisms? What are the five major groups of microorganisms?

Name three different habitats of microorganisms.

3. (a) Differentiate between antibodies and antibiotics.

(b) Define vaccine.

Microorganisms friends and foe Worksheet-15

Comprehension-Based Questions:

Microorganisms are classified into four major groups. These groups are bacteria, fungi, protozoa and some algae. Viruses are also microscopic. They, however, reproduce only inside the cells of the host organism, which may be a bacterium, plant or animal. Common ailments like cold, influenza (flu) and most coughs are caused by viruses. Serious diseases like polio and chicken pox are also caused by viruses. Diseases like dysentery and malaria are caused by protozoans. Typhoid and tuberculosis (TB) are bacterial diseases. Microorganisms are used for various purposes. They are used in the preparation of curd, bread and cake. They are also used in cleaning up of the environment. In agriculture they are used to increase soil fertility by fixing nitrogen.

1. In how many groups microorganisms are classified?

(A) Two              (B) Three           (C) Four             (D) Five

Microorganisms friends and foe Worksheet-16

True or False:

1. The living organisms which cannot be seen with naked eyes are called microorganisms.

2. Typhoid is caused by bacteria.

3. Tuberculxin is the toxin released by bacteria causing tuberculosis.

4. Tuberculosis is a viral disease.

5. Hepatitis A is a viral disease.

6. Cholera is transmitted through food and water.

7. Male anopheles mosquito is the carrier of malarial parasite.

8. Plasmodium is the malarial parasite.