Q1 of 50 Page 1

Name the two intermediate hosts which the human liver fluke depends on to complete its life cycle so as to facilitate parasitization of its primary host.

The human liver fluke depends mainly on three hosts:


In which two are intermediate hosts and one definitive host.


1. Firstly an infected host release eggs into the water by means of infected faeces. These eggs are then taken up by snails (which are the first intermediate host) where the eggs complete their gestation period and hatch to form worms.


2. Now,the worms leave the snail and enters the fish which are the second intermediate host.


First intermediate host: Snail


Second Intermediate host: Fish


Definitive Host: Human beings


More from this chapter

All 50 →
29

(a) Explain the process of DNA replication with the help of a schematic diagram.

(b) In which phase of the cell cycle does replication occur in Eukaryotes ? Whatwould happen if cell-division is not followed after DNA replication ?


OR


(a) Explain Darwinian theory of evolution with the help of one suitable example. State the two key concepts of the theory.


(b) Mention any three characteristics of Neanderthal man that lived in near east and central Asia.


 30

(a) Name the technology that has helped the scientists to propagate on large scale the desired crops in short duration. List the steps carried out to propagate the crops by the said technique.

(b) How are somatic hybrids obtained ?


OR


(a) Cancer is one of the most dreaded diseases of humans. Explain 'Contact inhibition' and 'Metastasis' with respect to the disease.


(b) Name the group of genes which have been identified in normal cells that could lead to cancer and how they do so ?


(c) Name any two techniques which are useful to detect cancers of internal organs.


(d) Why are cancer patients often given α-interferon as part of the treatment ?


 7

Mention how does DNA polymorphism arise in a population ?

 9

Name the organic materials the exine and intine of an angiosperm pollen grains are made up of. Explain the role of

exine.