LONG ANSWER TYPE
1. Explain the structure and life cycle
of Entamoeba histolytica with the help
2. Describe the life cycle of Plasmodium
QUESTIONS
of neat and labelled diagrams.
vivax in man.
3. Describe the life cycle of Plasmodium
vivax in mosquito.
4. Describe the structure and life cycle
of Ascaris lumbricoides with the help
of a neat and labelled diagram.
5. Describe the life cycle of Wuchereria
bancrofti.
Answers
Explanation:
Entamoeba histolytica (Gr. entos - within : amoiba - change histos - tissues ; lysis - dissolve) is a microscopic and monogenetic parasite that inhabits the large intestine and causes amoebic dysentery or amoebiasis in man. It is cosmopolitan in distribution but more common in the tropical and subtropical regions of the world. It is common in the people of rural and densely populated urban areas wherever the hygienic conditions are poor. Structure : Entamoeba histolytica passes through three distinct stages in its life cycle namely (i) Trophozoite stage (ii) Precystic stage & (iii) Cystic stage (i) Trophozoit stage : It is the most active, motile, feeding and pathogenic stage that lives in the mucosa and sub-mucosa membrane of the large intestine. It moves with the help of a lobopodium which is produced anteriorly. The body of the trophozoite is surrounded by plasma- lemma. Its cytoplasm is differentiated into outer clear, viscous non-granular ectoplasm and inner fluid like, granular endoplasm. Ribosomes, food vacuoles and vesicular, cartwheel shaped nucleus are present in the endoplasm. The absence of mitochondria indicates the obligate anaerobic nature of Entamoeba histolytica.