1007798
Description
Mind Map by Chloe.Sharland, updated more than 1 year ago
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Created by Chloe.Sharland
about 11 years ago
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B5e -
Digestion
- Physical digestion
- Physical digestion involves breaking food down into smaller pieces without making any chemical changes.
Physical digestion happens in: the mouth when food is chewed the stomach when food is squeezed and
moved around Physical digestion is important because it lets the food pass through the digestive system more
easily, and it provides a larger surface area for enzymes to work on.
- Physical digestion involves breaking food down into smaller pieces without making any chemical changes.
Physical digestion happens in: the mouth when food is chewed the stomach when food is squeezed and
moved around Physical digestion is important because it lets the food pass through the digestive system more
easily, and it provides a larger surface area for enzymes to work on.
- Chemical digestion
- Chemical digestion involves breaking large food molecules into smaller molecules using chemical reactions.
These smaller molecules can then be absorbed into the blood. Enzymes speed up chemical digestion. These
are natural catalysts made of proteins. Different enzymes catalyse different digestion reactions. Stomach acid
provides the correct pH for stomach protease to function properly. Different enzymes are produced in different
parts of the gut. carbohydrase enzymes catalyse the breakdown of starch into sugars in the mouth and small
intestine protease enzymes catalyse the breakdown of proteins into amino acids in the stomach and small
intestine lipase enzymes catalyse the breakdown of fats and oils into fatty acids and glycerol in the small
intestine
- Chemical digestion involves breaking large food molecules into smaller molecules using chemical reactions.
These smaller molecules can then be absorbed into the blood. Enzymes speed up chemical digestion. These
are natural catalysts made of proteins. Different enzymes catalyse different digestion reactions. Stomach acid
provides the correct pH for stomach protease to function properly. Different enzymes are produced in different
parts of the gut. carbohydrase enzymes catalyse the breakdown of starch into sugars in the mouth and small
intestine protease enzymes catalyse the breakdown of proteins into amino acids in the stomach and small
intestine lipase enzymes catalyse the breakdown of fats and oils into fatty acids and glycerol in the small
intestine
- Absorbtion
- The products of chemical digestion are absorbed into the body in the small intestine: sugars and amino acids
pass into the bloodstream by diffusion fatty acids and glycerol pass into the lymph The bloodstream and
lymph carry them to the body’s tissues.
- The intestine has several adaptations for the efficient absorption of small molecules from digestion: it has a
thin lining it has a good blood supply it is very long and has a large surface area Tiny finger-like projections
called villi provide a large surface area for absorption to take place. They also have a rich supply of blood
vessels to carry away absorbed molecules.
- The products of chemical digestion are absorbed into the body in the small intestine: sugars and amino acids
pass into the bloodstream by diffusion fatty acids and glycerol pass into the lymph The bloodstream and
lymph carry them to the body’s tissues.
- Parts of the digestive system
- Salivary glands
- produce saliva that moistens food and contains
carbohydrase enzymes
- produce saliva that moistens food and contains
carbohydrase enzymes
- Stomach
- produces hydrochloric acid and protease enzymes
- produces hydrochloric acid and protease enzymes
- Pancreas
- produces carbohydrase, protease and lipase enzymes
- produces carbohydrase, protease and lipase enzymes
- Liver
- produces bile
- produces bile
- Gall bladder
- stores bile
- stores bile
- Small intestine
- produces carbohydrase, protease and
lipase enzymes, and absorbs digested food
- produces carbohydrase, protease and
lipase enzymes, and absorbs digested food
- Large intestine
- absorbs water
- absorbs water
- Salivary glands
- Starch digestion
- Starch is a complex carbohydrate. Each molecule consists of very many glucose molecules joined together.
The digestion of starch is a two-stage process: it is first digested to form maltose (each maltose molecule
consists of two glucose molecules joined together) the maltose is then digested to form glucose
- Starch is a complex carbohydrate. Each molecule consists of very many glucose molecules joined together.
The digestion of starch is a two-stage process: it is first digested to form maltose (each maltose molecule
consists of two glucose molecules joined together) the maltose is then digested to form glucose
- Changing pH
- The pH is at alkaline levels in the mouth and small intestine, but the pH in the stomach is at acidic levels.
The enzymes there work at different optimum pH levels. For example: salivary amylase works best just below
pH 7 stomach protease works best at around pH 1.6 pancreatic lipase works best at around pH 8
- The pH is at alkaline levels in the mouth and small intestine, but the pH in the stomach is at acidic levels.
The enzymes there work at different optimum pH levels. For example: salivary amylase works best just below
pH 7 stomach protease works best at around pH 1.6 pancreatic lipase works best at around pH 8
- Bile
- As food passes from the stomach into the small intestine, the pH must be raised. Bile - an alkaline substance
- is released into the small intestine to achieve this. Bile also emulsifies (breaks down) fats in the small
intestine. This is important, because it provides a larger surface area in which the lipases can work.
- As food passes from the stomach into the small intestine, the pH must be raised. Bile - an alkaline substance
- is released into the small intestine to achieve this. Bile also emulsifies (breaks down) fats in the small
intestine. This is important, because it provides a larger surface area in which the lipases can work.
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