10. what are three differences between mechanical and chemical digestion.
To identify three differences between mechanical and chemical digestion, let's first understand the concepts of mechanical and chemical digestion.
Mechanical Digestion:
Mechanical digestion refers to the physical breakdown of food into smaller particles through mechanical means, such as chewing, grinding, and churning. It begins in the mouth with chewing and continues in the stomach and small intestine through muscle contractions.
Chemical Digestion:
Chemical digestion involves the breakdown of complex molecules into simpler substances through chemical reactions. It mainly occurs through the action of digestive enzymes that break down food into nutrients that can be absorbed by the body.
Now, let's explore the three differences between mechanical and chemical digestion:
1. Nature of Breakdown:
- Mechanical Digestion: In mechanical digestion, the breakdown of food occurs through physical actions like biting, chewing, and grinding. It breaks down food into smaller pieces, increasing the surface area for further digestion.
- Chemical Digestion: Chemical digestion involves the breakdown of food into simpler molecules by the action of enzymes, acids, and other substances. It breaks down complex carbohydrates, proteins, and lipids into simpler molecules like sugars, amino acids, and fatty acids.
2. Site of Action:
- Mechanical Digestion: Mechanical digestion starts in the mouth, where food is mechanically broken down by biting and chewing. It then continues in the stomach and small intestine, where muscular contractions help further break down the food and mix it with digestive juices.
- Chemical Digestion: Chemical digestion mainly occurs in the stomach and small intestine. Enzymes and acids released in the stomach, such as pepsin and hydrochloric acid, help break down proteins. In the small intestine, pancreatic enzymes, bile from the liver, and enzymes from the intestinal wall continue the process of chemical digestion.
3. Final Result:
- Mechanical Digestion: The main purpose of mechanical digestion is to physically break down food into smaller particles, facilitating further digestion and absorption. It increases the surface area of the food, making it easier for enzymes and other substances to act upon it.
- Chemical Digestion: The primary objective of chemical digestion is to break down complex molecules into simpler forms that can be absorbed by the body. Enzymes help convert carbohydrates into simple sugars, proteins into amino acids, and lipids into fatty acids.
In summary, mechanical digestion involves physically breaking down food into smaller pieces, while chemical digestion involves the use of enzymes to break down complex molecules into simpler substances. Mechanical digestion mainly occurs in the mouth, stomach, and small intestine, whereas chemical digestion primarily takes place in the stomach and small intestine. The end result of mechanical digestion is smaller food particles, while chemical digestion leads to simpler molecules ready for absorption.