Test: Microorganisms : Friend Or Foe - 2 - Class 8 MCQ

Influenza is an infectious disease caused by the influenza virus. It is also known as flu symptoms include high fever, running nose, sore throat, headache, coughing and muscles pain etc. Typhoid, dysentery and cholera are bacterial infections.

• Preservatives such as vinegar, common salt, and oil are used to prevent the spoilage of foods and protect them from microbial infection.
• Vinegar and salt create an environment that inhibits microbial growth, while oil can create a barrier to prevent microorganisms from reaching the food.
• Therefore, all of these substances are effective in preserving food in the kitchen.

• It produces carbon dioxide, causing dough to rise – This is the main role, as the carbon dioxide gas produced by yeast makes the dough expand and become fluffy.

Answer: B) Antibodies

- The body produces antibodies to fight disease-carrying microbes.
- Antibodies are crucial for identifying and eliminating harmful invaders, thus protecting the body from infections

- Penicillin is produced by a type of fungus.
- This discovery was made by Alexander Fleming in 1928.
- The specific fungus responsible for producing penicillin is *Penicillium notatum* (now known as *Penicillium chrysogenum*).
- Fungi, as microorganisms, reproduce by spores and can produce various antibiotics.
- Penicillin was the first true antibiotic used to treat bacterial infections effectively.
- This discovery revolutionized medicine by allowing the treatment of bacterial infections that were once lethal.

- The purpose of introducing dead or weakened microbes into the body is to stimulate the immune system.
- This process is known as vaccination.
- When introduced, the immune system recognizes these microbes as foreign invaders.
- The body responds by producing antibodies, which are proteins that specifically target and neutralize the microbes.
- This prepares the immune system to fight off future infections by the same microbe, providing immunity without causing the disease.

- Edward Jenner discovered the vaccine for smallpox.