what's the difference between mechanical and chemical digestion?

Question

what is the difference and could you give me an example?

Answer 1

mechanical digestion occurs when ur chewing...u chew the food, it gets mixed with saliva, alivary amylase digests the carbs in the food......so it's due to u mechanically moving ur mouth

chemical digestion occurs in ur stomach, intestine..etc....ur not doing anything voluntarily. it's due to chemicals secreted by organs...

Answer 2

Chewing would be mechanical and the stomach acids digesting the food would be chemical. Mechanical means action/movement and chemical is when an acid is used to digest.

Answer 3

Chemical digestion needs a mechanical break down of food by comminution (grinding etc.) so that more surface area of the substance is exposed to the chemicals which are trying to digest it. There is no purely mechanical digestion as far as I know.

Answer 4

Chemical digestion uses pepsin and other secretions used to break down food. Pepsin breaks down proteins (i think). The use of chemical to break foods down.

Mechanical digestion is like the churning of food in the stomach. Mechanical generally refers to movement of muscle to mash the food up. Or the chewing of food is a real good example of mechanical digestion.

Answer 5

Mechanical digestion involves the use of the muscles of mastication. Chewing your food breaks the food down into smaller particles, thus exposing more surface area to digestive enzymes.

Chemical digestion takes place in several different locations and is the work of enzymatic properties. For ease of understanding, I will break the foodstuffs down into the three major energy sources.

Carbohydrates: chemical digestion starts in the mouth with salivary amylase (also called ptyaline). This breaks larger sugars (such as starches) down into smaller sugars. Once the food enters the first portion of your small intestine (the duodenum), pancreatic amylase does the majority of the carbohydrate digestion, breaking sugars down into disaccharides (such as maltose, lactose, etc.) Enzymes located in the brush border of the small intestine then break the disaccharides down into monosaccharides (e.g., lactase breaks lactose down into glucose and galactose). These monosaccharides are the absorbed by the small intestinal cells.

Protein: no chemical digestion of protein occurs until the food enters the stomach. There, acid helps to denature the protein, destroying its tertiary and quatrinary structure, and converting it into a strand of polypeptides. In the small intestine, pancreatic enzymes (such as trypsin, chymotrypsin, carboxypeptidase, etc) break the proteins down into smaller protein strands consisting of a few amino acids. Again, small intestinal enzymes called enterokinases break these down into individual amino acids that are absorbed by the small intestinal mucosa.

Fats: chemical digestion of fat starts in the duodenum when bile released from the gallbladder emulsifies the fat, and allows pancreatic amylase to digest the fats into free fatty acids and glycerol. These products are then absorbed into the lymphatics surrounding the small intestine (called lacteals) and are dumped into the blood stream at the thoracic duct.

Answer 6

grinding salt in a mortar and pestle is mechanical.
dissolving salt in water is chemical.

The difference is that mechanical is the application of force to do the work, whereas chemical is a molecular force that does the work.