Question 1

Who proposed the five-kingdom system of classification?

Accepted Answer

R.H. Whittaker proposed the five-kingdom system of classification in 1969. The kingdoms defined by him were Monera, Protista, Fungi, Plantae, and Animalia, based on cell structure, thallus organization, mode of nutrition, reproduction, and phylogenetic relationships.

Question 2

Which of the following organisms are known as chief producers in the oceans?

Accepted Answer

Diatoms are the chief producers in the oceans. They belong to Chrysophytes (Kingdom Protista) and have cell walls embedded with silica, making them indestructible and leaving behind large diatomaceous earth deposits.

Question 3

An infectious protein particle lacking nucleic acid is known as:

Accepted Answer

Prions are infectious protein particles that lack nucleic acids. They are responsible for several neurological diseases such as bovine spongiform encephalopathy (BSE) in cattle and Creutzfeldt-Jakob disease (CJD) in humans.

Question 4

Contagium vivum fluidum was coined by:

Accepted Answer

M.W. Beijerinck demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants and called the fluid as 'Contagium vivum fluidum' (infectious living fluid).

Question 5

The fungal component of a lichen is called:

Accepted Answer

In lichens, the fungal component is known as mycobiont and the algal component is known as phycobiont. The mycobiont is heterotrophic and provides shelter, water, and minerals to the algae.

Biological Classification — NCERT Class 11 Biology Important Questions & Revision Notes