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10 Cards in this Set
- Front
- Back
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6.1.1 Large food molecules in digestion is essential because....
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Food is made up of many compounds by other organisms which are not all suitable for human tissue and have to be broken down then reassembled for bodily usage.
And food molecules have to be small enough to be absorbed the villie in intestines through diffusion, facillitated diffusion or active transport so large food molecules need to be broken down into smaller ones for absorbtion to occur. |
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6.1.2 Why is enzymes needed in digestion?
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They are biological catalysts which break down the large food molecules so it can be absorbed.
Digestion can occur in normal body temperature but it takes a long time, as a higher body temperature might speed up reaction is not possible because it would interfere with other body functions, enzymes are vital in speeding up the process by lowering the activation energy required |
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6.1.3 Amylase
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Enzyme- salivary amylase
Source-salivary glands Substrate-starch Products-maltose Optimum pH-ph7 |
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6.1.3 Protease
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Enzyme- pepsin
Source-stomach lining Substrate-proteins Products-small polypeptides Optimum pH-ph 1.5-2 |
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6.1.3 Lipase
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Enzyme- pancreatic lipase
Source-pancrease Substrate-triglycerides such as fats/oil Products-fatty acids and glycerol Optimum pH- 7 |
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6.1.5 Stomach
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Secretes HCL which kills bacteria and harmful organsims preventing food poisoning
HCL also provudes optimum ph level(1.5-2) for pepsin to work Pepsin starts digestion by breaking proteins into polypeptides and amino acids |
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6.1.5 Small intestines
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Secretes enzymes and also recieevs fro pancrease.
Absorption of small food particles by villi that has a huge surface area |
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6.1.6 Large intestines
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Moves material that has not been digested and absorbs water.
Produces faeces |
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6.1.6 Distinguish between absorption and assimilation.
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Absorption occurs when food molecules pass through layer of cells into the tissues in the small intestine (villi) while assilimilation occurs when food molecules becomes part of the tissue.
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6.1.7 How does the villus promote absorption in small intestines?
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-huge number the villi increases the surface area for absoprtion.
-has their own projections which are called microvilli which also enhances absorption. : Microvili have protein chanels and pumps in membranes to allow rapid absorption of food by facilitated diffusion and active transport) -Contains an epithelial layer which is really thin so food can pass through membrane easily -Blood capillaries are very closely associated so that distance for diffusion of food molecules is small. -Thin layer of cell contains mitochondria to provide ATP for active transport -Lacteal branch carries away fats after absoprtion. |
