Heterotrophic nutrition is a mode of nutrition in which organisms obtain their organic molecules and energy by consuming other living or dead organisms. This is in contrast to autotrophic nutrition, in which organisms can produce their organic molecules through processes like photosynthesis.

Heterotrophic Nutrition In Amoeba

Amoeba is a unicellular, microscopic organism that primarily lives in freshwater environments. It exhibits heterotrophic nutrition through a process known as phagocytosis. The steps involved in Amoeba’s nutrition are as follows

• Phagocytosis: Amoeba extends its pseudopodia (temporary projections of its cell membrane) around a small particle of food, such as a bacterium or algae.
• Ingestion: The pseudopodia surround and engulf the food particle, forming a food vacuole.
• Digestion: Enzymes are released into the food vacuole to break down the ingested food into simpler substances.
• Absorption: Nutrients, including amino acids, sugars, and other small molecules, are absorbed into the amoeba’s cytoplasm.
• Elimination: Undigested remnants are eliminated from the cell through exocytosis.

Heterotrophic Nutrition in Paramecium

Paramecium is another unicellular protist that also exhibits heterotrophic nutrition. It uses cilia for locomotion and has specialized structures called trichocysts for defense. The process of heterotrophic nutrition in Paramecium involves:

• Food Ingestion: Paramecium sweeps food particles, such as bacteria and small algae, into its oral groove using cilia.
• Formation of Food Vacuoles: The ingested food particles are surrounded by a membrane to form food vacuoles.
• Digestion: Within the food vacuoles, enzymes break down the food into simpler molecules.
• Nutrient Absorption: The digested nutrients are absorbed into the cytoplasm of the Paramecium.
• Elimination: Waste materials are expelled from the cell through an anal pore.

Heterotrophic Nutrition in Humans

Humans are multicellular animals that exhibit heterotrophic nutrition. The process in humans involves several steps:

• Ingestion: Food is taken into the body through the mouth.
• Mechanical Digestion: In the mouth, food is chewed and mixed with saliva to form a bolus, which facilitates swallowing.
• Chemical Digestion: In the stomach, food is mixed with gastric juices containing hydrochloric acid and pepsin, which break down proteins.
• Nutrient Absorption: In the small intestine, nutrients are absorbed into the bloodstream through the walls of the intestine.
• Elimination: Undigested food and waste materials are eliminated from the body through the rectum and anus.