Nutrition Essay

Holozoic nutrition (Gr. holo means-whole ; zoikos means-of animals) is a method of nutrition that involves the ingestion of liquid or solid organic material, digestion, absorption and assimilation of it to utilize it. It includes taking in the complex substances and converting them into simpler forms. Example, proteins can be broken into amino acids. This method suggests phagocytosis where the cell membrane completely surrounds a food particle[pic] Parasitic Nutrition is a mode of heterotrophic nutrition where an organism (known as a parasite) lives on the body surface or inside the body of another type of organism (known as a host). The parasite obtains nutrition directly from the body of the host. Since these parasites derive their nourishment from their host, this symbiotic interaction is often described as harmful to the host. Parasites are dependent on their host for survival, since the host provides nutrition and protection. As a result of this dependence, parasites have considerable modifications to optimise parasitic nutrition and therefore their survival. Saprotrophic nutrition (pron.: /sà ¦prÉ µÃ‹Ë†trÉ’fÉ ªk/) is a process of chemoheterotrophic extracellular digestion involved in the processing of dead or decayed organic matter. It occurs in saprotrophs or heterotrophs, and is most often associated with fungi, for example Mucor and Rhizopus. The process is most often facilitated through the active transport of such materials through endocytosis within the internal mycelium and its constituent hyphae.[1] Autotrophic Nutrition The term autotroph has been derived from two Greek wards-auto means self and troph means nutrition. In this mode of nutrition, the organisms prepare their own food from simple raw materials like water, carbon dioxide and mineral salts in the presence of sunlight. Chlorophylls present in the chloroplast or green plants are the site of food production. Accordingly all green plants are the examples of this category. The process by which they synthesize food is known as photosynthesis. Some nongreen becteria like sulphur bacteria can use energy which they derive from some chemical reactions occurring in them. With this energy they manufacture their food. This process is called chemosynthesis. Thus the autotrophs include both the photosynthetic and che4mosynthetic organisms. Heterotrophic Nutrition The word heterotrophy has been derived from two Greek words-hetero means different and troph refers to nutrition of food. The organisms which derive their food from others are known as heterotrophic organisms. They depend for their food on other organisms, hence they are called consumers. All animals, human beings and non-green plans like fungi come under this category. They consume complex organic food prepared by autotrophs or producers and break it into simple from to derive nourishment. Thus the difference between heterotrophy and autotrophs is basically in the mode of production of food. Due to lack of chlorophyll, heterotrophs cannot synthesize their food while autotrophs can perform photosynthesis.