Solution:

Fill in the blanks.

(a) Microorganisms can be seen with the help of a microscope.

(b) Blue green algae fix nitrogen directly from air and enhance fertility of soil.

(c) Alcohol is produced with the help of yeast.

(d) Cholera is caused by Vibrio cholerae.

Solution:

(a) Yeast is used in the production of 


(b) The following is an antibiotic 


(c) Carrier of malaria-causing protozoan is 


(d) The most common carrier of communicable diseases is 


(e) The bread or idli dough rises because of


(f) The process of conversion of sugar into alcohol is called


Solution:

Match the organisms in Column A with their action in Column B

Solution:

Can microorganisms be seen with the naked eye? If not, how can they be seen?

No, microorganisms cannot be seen with the naked eye because they are too small. They are microscopic in size and require a magnifying instrument to be observed. The most common instrument used to view microorganisms is a microscope. A microscope uses lenses to magnify small objects, making it possible to see microorganisms that are otherwise invisible to the human eye.

Solution:

Major Groups of Microorganisms

Microorganisms are classified into the following major groups:

• Bacteria: Single-celled organisms that can be found in various environments, including soil, water, and living organisms.
• Fungi: Organisms that include molds, yeast, and mushrooms. They can be unicellular or multicellular and are found in decaying organic matter.
• Algae: Simple, autotrophic organisms that can perform photosynthesis. They are found in water and moist environments.
• Protozoa: Single-celled eukaryotic organisms that live in water or as parasites in other organisms.
• Viruses: Non-living infectious agents that require a host cell to replicate. They are much smaller than bacteria and can cause diseases.

Solution:

Microorganisms that can fix atmospheric nitrogen in the soil

The microorganisms that can fix atmospheric nitrogen in the soil include:

• Rhizobium – A bacterium that forms symbiotic relationships with leguminous plants.
• Azotobacter – A free-living bacterium found in the soil that can fix nitrogen.
• Clostridium – A genus of bacteria that also fixes nitrogen, particularly in anaerobic conditions.
• Frankia – A bacterium that forms symbiotic relationships with actinorhizal plants.

Solution:

Usefulness of Microorganisms in Our Lives

1. Microorganisms play a key role in the nitrogen cycle, helping in the conversion of atmospheric nitrogen into forms usable by plants.

2. They are essential in the process of fermentation, used in making food items like yogurt, cheese, and bread.

3. Some microorganisms, like bacteria, help in breaking down organic matter, which aids in recycling nutrients in the soil.

4. Microorganisms are involved in the production of medicines, such as antibiotics, which help in treating infections.

5. They are used in the production of biofuels, such as ethanol, which serve as an alternative to fossil fuels.

6. Microorganisms help in the cleaning of oil spills through a process known as bioremediation.

7. Some microorganisms are used in the preparation of vaccines, helping in disease prevention.

8. They assist in the digestion of food in the intestines, particularly in humans and animals.

9. Microorganisms are used in the treatment of wastewater, helping to purify it before it is released into the environment.

10. Certain microorganisms, like algae, are important in producing oxygen and serve as a base in aquatic food chains.

Solution:

Harmful Effects of Microorganisms

Microorganisms can have several harmful effects on humans, animals, and plants. Some microorganisms cause diseases such as tuberculosis, malaria, and cholera in humans, while others can cause infections in animals and plants. Pathogenic bacteria, viruses, fungi, and protozoa are responsible for these illnesses. Additionally, microorganisms can spoil food, leading to foodborne illnesses. They also play a role in the decay of organic matter, which can sometimes result in the contamination of water sources and the spread of harmful diseases.

Solution:

What are Antibiotics?

Antibiotics are medicines that are used to treat infections caused by bacteria. They work by either killing the bacteria or preventing their growth. Antibiotics are not effective against viral infections such as the flu or common cold.

Precautions to be Taken While Taking Antibiotics

• Complete the full course of antibiotics even if you feel better before finishing the medicine. Stopping early can lead to the infection returning and antibiotic resistance.
• Take the antibiotics exactly as prescribed by the doctor. Do not skip doses or take extra doses.
• Avoid alcohol consumption while on antibiotics as it may interfere with the effectiveness of the medication or cause side effects.
• Do not share your antibiotics with others, even if they have similar symptoms. Each antibiotic prescription is specific to the individual and their condition.
• If you experience any allergic reactions or side effects such as rashes, swelling, or difficulty breathing, seek immediate medical attention.
• Do not take antibiotics for viral infections like the flu or common cold, as they are ineffective against viruses.
• Inform the doctor if you are pregnant, breastfeeding, or taking any other medications to avoid possible drug interactions.