Biology Study Guide

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Biology Qs 2 (a) (i) A = HUMAN LIVER (ii) B = HUMAN RED BLOOD CELLS (iii) C = MOSQUITO INTESTINE (iv) D = MOSQUITO SALIVARY GLAND 2 (b) Adult flatworm releases egg: INSIDE HUMAN HOST Egg hatches to become miracidium larva: FREE LIVING IN FRESH WATER Miracidium larva becomes a cercaria larva: INSIDE SNAIL HOST Cercaria larva develops into an adult flatworm: INSIDE HUMAN HOST 2 (c) The plasmodium parasite would be most susceptible to human antibodies between the moment of initial infection and the arrival of the larvae in the liver, as it travels through the bloodstream in the form of sporozytes. Here the parasite is fully exposed, not ensconced in liver cells or red blood cells as during later phases of its development. Though the lower numbers of parasites at this stage would trigger less of an antibody response, this lower plasmodium population would also be more effectively countered by the human body's natural defenses. 2 (d) i. 1. Multiple or even hermaphroditic reproductive organs to increase reproductive chances 2. Morphological flattening to ease remaining on/travelling in a host organism ii. Plasmodium: 1. The ability to seek out the human liver, which might provide essential fatty acids the plasmodium parasite cannot produce on its own, is one important adaptation of this organism. 2. The sporozyte phase of the plasmodium life cycle, which provides a great deal of morphological (i.e. directly physical and not necessarily chemical) protection for
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