Final answer:
The sandwich is mechanically and chemically broken down into its component molecules by enzymes, resulting in nutrients that can be absorbed and used by the body's cells for energy and the synthesis of new cellular components.
Step-by-step explanation:
When a person consumes a sandwich consisting of white bread, chicken, mayonnaise, lettuce, and tomato, different components are broken down by the digestive system. The process begins with chewing, where mechanical breakdown occurs, then continues with chemical digestion where enzymes play a crucial role. These enzymes catalyze organic chemical reactions breaking down macromolecules such as carbohydrates, proteins, and lipids into their constituent monomers—sugars, amino acids, fatty acids, and glycerol.
Enzymes act as catalysts, speeding up reactions without being consumed, making them crucial in converting matter that contains carbon, hydrogen, oxygen, and nitrogen from complex to simple forms. For example, the enzyme amylase begins the digestion of carbohydrates in the mouth, converting them to simpler sugars. This process continues in the stomach and small intestine where proteins are broken down by pepsin and other enzymes.
These reactions, such as the breakdown of glucose to release energy, are exergonic, meaning they release energy. Conversely, using the amino acids to build new proteins is an example of an endergonic reaction where energy is consumed. The overall process results in nutrients being made available to cells for energy production and the synthesis of new cellular components.