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B2 E) Digestive Enzymes, Bile & Stomach Acid
B2 E) Digestive Enzymes, Bile & Stomach Acid
Digestive enzymes break down larger molecules into smaller molecules (the products of digestion). The larger molecules need to be broken down because they are too large to pass through the walls of the digestive system into the bloodstream. There are many different enzymes in the human body, and these are the ones that you need to know.
Carbohydrases
Carbohydrases are enzymes that break down carbohydrates into simple sugars.
An example of carbohydrase is amylase, which breaks down starch into maltose.
Carbohydrases are enzymes that break down carbohydrates into simple sugars.
An example of carbohydrase is amylase, which breaks down starch into maltose.
Amylase is made in the salivary glands (located in the mouth), the small intestine and the pancreas.
Protease
Protease breaks down proteins into amino acids.
Protease breaks down proteins into amino acids.
Protease is made in the small intestine, pancreas and the stomach (in the stomach, protease is called pepsin).
Lipase
Lipase breaks down lipids into glycerol and fatty acids.
Lipase breaks down lipids into glycerol and fatty acids.
Lipase is made in the small intestine and pancreas.
The Products
After these enzymes have broken down the larger molecules into smaller molecules (the products of digestion), the smaller molecules enter the bloodstream and cells. The products of digestion will then be made into new carbohydrates, lipids and proteins. Some of the glucose made from digestion is used for respiration.
After these enzymes have broken down the larger molecules into smaller molecules (the products of digestion), the smaller molecules enter the bloodstream and cells. The products of digestion will then be made into new carbohydrates, lipids and proteins. Some of the glucose made from digestion is used for respiration.
Bile & Stomach Acid
The stomach produces hydrochloric acid, which has a pH of around 2. The stomach is acidic as acidic conditions helps digestion and kills potentially harmful microorganisms that may have been swallowed (the killing of microorganisms means that they do not harm us – we do not get infected with them). An example of an enzyme that is found in the stomach is pepsin.
The products of the stomach pass onto the small intestine. The enzymes in the small intestine work best in alkaline conditions. However, the products leaving the stomach are very acidic. Therefore, the body needs to convert the products of the stomach from being acidic to becoming alkaline, which it does by using bile. Bile is a strong alkali, which neutralises the products from the stomach and makes them slightly alkaline (the optimal conditions for the enzymes in the small intestine to work). Bile is produced in the liver and stored in the gall bladder before it is released into the small intestine.
Bile also emulsifies fats, which means that the fats become tiny droplets. These tiny droplets offer a greater surface area for the lipase enzyme to work with compared to one big droplet of fat. This results in faster digestion.
The stomach produces hydrochloric acid, which has a pH of around 2. The stomach is acidic as acidic conditions helps digestion and kills potentially harmful microorganisms that may have been swallowed (the killing of microorganisms means that they do not harm us – we do not get infected with them). An example of an enzyme that is found in the stomach is pepsin.
The products of the stomach pass onto the small intestine. The enzymes in the small intestine work best in alkaline conditions. However, the products leaving the stomach are very acidic. Therefore, the body needs to convert the products of the stomach from being acidic to becoming alkaline, which it does by using bile. Bile is a strong alkali, which neutralises the products from the stomach and makes them slightly alkaline (the optimal conditions for the enzymes in the small intestine to work). Bile is produced in the liver and stored in the gall bladder before it is released into the small intestine.
Bile also emulsifies fats, which means that the fats become tiny droplets. These tiny droplets offer a greater surface area for the lipase enzyme to work with compared to one big droplet of fat. This results in faster digestion.