(a) (i) Name the protozoan species that is responsible for causing the most serious and even fatal malarial disease. (ii) Name the host in which the…

Plasmodium falciparum

$\displaystyle \diamond$ Female Anopheles Mosquito

$\displaystyle \diamond$

Mosquito picks up gametocytes from the infected person.

Fertilization and development takes place in mosquito gut.

Sporozoites from gut migrate to salivary glands of mosquito.

After entering the blood stream they enter liver, and then into red blood cells and reproduce asexually, RBCs rupture and a toxic substance haemozoin is released causing chills and high fever.

$\displaystyle \diamond$ Avoiding stagnation of water in and around residential areas.

$\displaystyle \diamond$ Regular cleaning of household coolers.

$\displaystyle \diamond$ Use of mosquito nets.

$\displaystyle \diamond$ Introduce fishes like Gambusia in ponds – they feed on mosquito larval.

$\displaystyle \diamond$ Spraying insecticides in ditches of doors and windows to have wire mesh.

$\displaystyle \diamond$Any other appropriate preventive measures.

(Any two)

Bio fertilizers – Organisms that enrich the nutrient quality of soil. e.g. bacteria fungi and cyanobacteria.

$\displaystyle \diamond$ Bacteria / Rhizobium / Azotobacter / Azospirillum

Rhizobium forms symbiotic association with roots of leguminous plants and fix atmospheric nitrogen into organic forms to be used by the plant,

Azotobacter or Azospirillum fix atmospheric nitrogen while free living in the soil.

$\displaystyle \diamond$ Fungi /genus Glomus .

Fungi breakdown organic matter to release nutrients,

Glomus form mycorrhiza with roots of the plants.This association helps to absorb phosphorous from soil and pass to the plant, plants show resistance to root-borne pathogens, plants show tolerance to salinity and drought,

There is increase in plant growth.

$\displaystyle \diamond$ Cyanobacteria / Anabaena / Nostoc / Oscillatoria (Any one)

Fix atmospheric Nitrogen, serve as important biofertilizers in paddy fields (Any one)

-Bio fertilizers do not pollute our environment (soil, ground water).

$\displaystyle \diamond$ They conserve the beneficial soil microbes.

$\displaystyle \diamond$ Do not cause contamination and harm human health.

(Any two)