HUMAN NUTRITION

Detailed explanation-1: -The large molecules found in intact food cannot pass through the cell membranes. Food needs to be broken into smaller particles so that animals can harness the nutrients and organic molecules. The first step in this process is ingestion. Ingestion is the process of taking in food through the mouth.

Detailed explanation-2: -In either case, the large polymeric molecules in food are broken down during digestion into their monomer subunits-proteins into amino acids, polysaccharides into sugars, and fats into fatty acids and glycerol-through the action of enzymes.

Detailed explanation-3: -The complex molecules of carbohydrates, proteins, and fats are transformed by chemical digestion into smaller molecules that can be absorbed and utilized by the cells. Chemical digestion, through a process called hydrolysis, uses water and digestive enzymes to break down the complex molecules.

Detailed explanation-4: -Chemical digestion is the biochemical process in which macromolecules in food are changed into smaller molecules that can be absorbed into body fluids and transported to cells throughout the body. Substances in food that must be chemically digested include carbohydrates, proteins, lipids, and nucleic acids.