CBSE Questions for Class 11 Medical Biology Biological Classification Quiz 1 - MCQExams.com

• Antibiotics or antibacterials are medications that destroy or slow down the growth of bacteria.
• The antibiotics have no effect on viruses because viruses show no metabolism of their own. Viruses are non-living entities and as such do not inherently have their own metabolism.
  
• Hence the antibiotics have no effect on viruses because viruses show no metabolism(ability to collect and use energy) of their own.
• So, the correct answer is 'viruses show no metabolism of their own'

• Adenoviruses are a group of viruses that typically cause respiratory illnesses, such as a common cold, conjunctivitis (infection in the eye),  bronchitis, or pneumonia. In children, adenoviruses usually cause infections in the respiratory tract and intestinal tract.
  
• The Potato spindle tuber viroid was the first viroid to be identified. It is a small, single-stranded circular RNA molecule, infecting potatoes and tomatoes.
  
• Tobacco mosaic disease is caused by the bacteriophage  Tobacco mosaic virus, a single stranded RNA virus. It infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves.
• A prion is a type of protein that can trigger normal proteins in the brain to fold abnormally, leading to diseases like Alzheimer's disease and Creutzfeldt-Jakob disease (CJD).
  

We find a wide variety of viruses, while the smallest virus is the one causing foot and mouth disease, also called as FMDV. The disease caused by the airborne virus is very highly communicable transmitting up to many kilometers but virus is as small as 0.008 to 0.012 microns.

• The virus is non living infectious particle, hence, they can be crystallized. 
• The tobacco mosaic virus was the first virus to be crystallized. It was achieved by W M Stanley in 1935 who also showed that TMV remains active even after crystallization. For his work, he was awarded Nobel Prize in Chemistry in 1946.

• In Vedic times, the living organisms were divided into 3 classes. They are-

1. Born from the womb (Jivagi)
2. Born from egg (Andaja)
3. Born from sprouts (Udbhija)
   So, the correct answer is option B. 

• A prion is an abnormal form of a normally harmless protein found in the brain that is responsible for a variety of fatal neurodegenerative diseases of animals including humans. 
• All prion diseases in mammals affect the structure of the brain or other neural tissue and have no known effective treatment. 
• Prion diseases are always fatal. 
• Creutzfeldt Jakob disease is the prion disease in humans.