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10 Cards in this Set
- Front
- Back
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Briefly describe what is the digestive system
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- A long tube, opening at both ends and varying in width
- Know as: digestive system, digestive tract, gut and alimentary canal - Food eaten by animals is made up of large, inorganic compounds that can't pass through cell walls, therefore, it must be digested - Mechanical and chemical digestion breaks down complex nutrient molecules for the body to use |
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What is mechanical digestion?
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- The physical breakdown of large food particles into smaller particles
- Increases the surface area of food to be digested - Occurs mainly in the mouth - The movement of the muscles in the digestive system aid digestion |
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What is chemical digestion?
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- Breakdown of large molecules into smaller ones
- Takes place in the mouth, stomach and small intestine - Can be extra or intercellular - An enzymes mediates the chemical breakdown of each type of carb, protein or lipid |
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What does chemical digestion involve?
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a) Glads in which chemical compounds are built up and then secreted (e.g. salivary glads secrete saliva)
b) Enzymes which are catalysts found in tissue. Catalysts speed up the rate of reaction and they don't get used up in the reaction |
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Amylase: substrate acted upon, where is it found and what is the source of the enzyme?
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Substrate acted upon: Carbs
Found: - Saliva - Small Intestine Source: - Salivary glands - Pancreas and walls of Small Intestine |
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Protease: substrate acted upon, where is it found and what is the source of the enzyme?
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Substrate acted upon: Proteins
Found: - Stomach (pepsin) - Small Intestine Source: - Stomach wall - Pancreas - Wall of Small Intestine |
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Lipase: substrate acted upon, where is it found and what is the source of the enzyme?
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Substrate acted upon: Lipids (fats and oils)
Found: - Small Intestine Source: - Pancreas - Wall of Small Intestine |
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What is the structure and function of the mouth (teeth and tongue) and salivary glands?
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- First stage of digestion occurs here
- 3 sets of salivary glands - Saliva is an alkaline substance containing water, mucus and enzymes that coat the food and begin chemical digestion - Teeth break up food into smaller pieces called mastication creating a greater surface area for digestive enzymes to digest food - Tongue forms food into a bolus, which is swallowed |
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What is the structure and function of the Oesophagus?
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- Approx. 25cm, muscular tube
- Transports food from the mouth to the stomach via muscular contractions called 'peristalsis' |
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What is the structure and function of the stomach?
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- 'J' shaped muscular bag
- Churns food with muscular walls - Produces protease Produces HCl acid to kill bacteria and give the right pH for the protease enzyme to work |
