Question 11. Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.

Answer: Structure of viruses: Viruses have a protein capsule and genetic materials inside the capsule. These genetic material become active once they are inside the nucleus of a host cell. They start replicating themselves and in turn spreading the disease.

Generally viruses that infect plants have single stranded RNA. Viruses infecting animals have double stranded RNA or DNA. Viruses which infect bacteria have double stranded DNA.
 

Four Common Viral Diseases:

(a) AIDS

(b) Small Pox

(c) Herpes

(d) Swine Flu

 

Question 10. What are the characteristic features of Euglenoids?

Answer: Characterisitic Features of Euglenoids:

(a) Fresh water organisms found in stagnant water.

(b) Instead of cell wall they have a protein rich layer called pellicle whick makes their body flexible.

(c) They are autotrophs in the presence of sunlight and heterotrophs in the absence of sunlight.

Question 9. Give a comparative account of the classes of Kingdom Fungi under the following: (i) mode of nutrition (ii) mode of reproduction

Question 8. What do the terms phycobiont and mycobiont signify?

Answer: Lichens are good examples of symbiotic life of algae and fungi. Phycobiont is the name of the part composed of algae and Mycobiont is the name of the part composed of fungi. Fungi provide minerals and support to the alage, while algae provide nutrition to the fungi.

Question 7. Plants are autotrophic. Can you think of some plants that are partially heterotrophic?

Answer: Certain insectivorous plants, like bladderwort and venus fly trap are partially heterotrophic.

Question 6. Describe briefly the four major groups of Protozoa.

Answer: Four major groups of Protozoa is as follows:

(a) Amoeboid Protozoa: They are found in fresh water, sea water or moist soil. They have pseudopodia like amoeba, hence the name amoeboid protozoa.

(b) Flagellated Protozoans: They have flagella for movement. They are either free living or parasitic.

(c) Ciliated Protozoans: They have thousands of cilia present all over the body. The cilia helps in locomotion and steering of food into the gullet.

(d) Sporozoans: Many protozoans have an infectious spore-like stage in the life cycle. The spore-like stage helps them get transferred from one host to another host.