Biology
Assertion (A): The viruses are extremely small substances made of nucleic acids (DNA) and histones.
Reason (R): Viruses are considered as a connecting link between the living and non-living beings as they can multiply and be crystallized and stored for years.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Answer
A is False and R is True.
Reason — Viruses are extremely small and are made of: A nucleic acid core (either DNA or RNA, never both), and a protein coat called a capsid. However, viruses do not contain histones.
Viruses behave like living organisms when inside a host cell (they replicate), and like non-living things outside a host (they can be crystallized and stored without metabolism or reproduction).
Related Questions
Assertion (A): The disease-causing germs are called vectors.
Reason (R): The transmission of germs from one person to another is carried out by certain organisms which are termed as vectors.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Assertion (A): Taeniasis is the disease caused by tapeworms. It spreads by eating infected pork or beef.
Reason (R): Pigs or cows accidentally ingest the eggs of tapeworm which later on form larval stages. These larvae settle in the muscles of pigs or cows.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Correct the following statements by changing the first/last word only.
(a) Sporadic diseases are widely distributed worldwide.
(b) Yellow fever is an epidemic disease.
(c) Chicken pox is caused by a bacterium.
(d) Haemophilia is a kind of an allergy.
(e) Ascariasis is caused by a tapeworm.
Write the full forms of the following abbreviations:
(a) HIV
(b) AIDS
(c) BCG
(d) COVID-19
(e) RNA