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19 Cards in this Set
- Front
- Back
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what is the structure and function of the oesophagus? |
. carries food from the mouth to the stomach . adapted for transport rather than digestion . made up of a thick muscular wall |
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what is the structure and function of the stomach? |
. muscular sac with an inner layer that produces enzymes . role is to store and digest food . glands produce enzymes and mucus |
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what is the structure and the function of the small intestine? |
. long muscular tube . further digested here by enzymes secreted in its walls and by glands that pour their secretions into it . inner walls are filed into vili which are folded into micro villi . this increases surface area for faster and more efficient absorption into the bloodstream |
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what is the function of the large intestine? |
. absorbs water . undigested food becomes thicker and forms faeces |
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what is the function of the rectum? |
. final section of digestion . faeces are store until egestion (pooing) |
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what is the function of the salivary glands and where are they located? |
. located near the mouth . secrete through ducts into the mouth . enzyme amylase, starch - maltose |
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where is the pancreas located and what are its functions? |
. large gland situated below the stomach . produces pancreatic juice and other stuff . contains proteases, amylase and lipase to digest proteins, starch and lipids |
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what does physical digestion consist of? |
. when for is large it is broken down into smaller pieces by means as such as the teeth and peristalsis of the stomach . larger surface area, for chemical digestion |
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what does chemical digestion consist of? |
. large insoluble molecules into smaller soluble ones . carried out by enzymes . these function by hydrolysis - hydrolases . these are proteases, lipases and carbohydrases . glycerol, fatty acids, amino acids and monosaccharides are absorbed into the blood in the small intestine . assimilation is the build up of these again |
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how are are large molecules like carbohydrates constructed? |
. individual molecules make up monomers . many monomers make up polymers . most are made up of just four compounds . carbon, hydrogen, nitrogen and oxygen |
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what is a monomer and polymer of carbohydrate called? |
. monosaccharide 1 monomer . disaccharide 2 monomers . polysaccharide 3+ monomers |
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describe the general monosaccharide features |
. soluble, sweet tasting . best known monosaccharide is glucose . C6H12O6 . can be arranged in many different ways although mostly shown as a chain . all are reducing sugars |
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what is the test for reducing sugars? |
. Benedicts test . Benedicts is a alkaline copper (II) sulphate . when a reducing sugar is heated with been edicts it forms a red precipitate of copper (I) oxide . add 2cm3 of food sample to tube . add equal Benedicts . heat mixture gently in boiling water bath for 5 mins . if sugar present; low - yellow medium - orange brown high - red
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how are monosaccharides linked together to form disaccharides? |
. a glycosidic bond is formed by a condensation reaction . glucose glucose: maltose . glucose fructose: sucrose . glucose galactose: lactose |
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what is the test for non reducing sugars? |
. if tested with benedicts and results appear negative, then there may still be a non reducing sugar present . boil with HCL and then neutralise solution with dilute hydrochloric acid . heat sample again with Benedict's . stays blue - no non reducing sugars . red, yellow, orange brown, non reducing sugar is present |
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what is the test for starch? |
. starch is a polysaccharide made up of many alpha glucose molecules . iodine test . place 2cm3 of sample in test tube . two drops of potassium iodine to sample . presence of starch is indicated by a blacky-blue colour |
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describe the breakdown of eating starch to alpha glucose in the small intestine |
. food taken into the mouth and chewed by the teeth - larger surface area . saliva enters the mouth from salivary glands secreting salivary amylase . hydrolyses any starch into maltose . food is swallowed and churned in the stomach and the acidic conditions denature the amylase . food is passed into the small intestine where it mixes with pancreatic juice . here pancreatic amylase breaks down maltose into alpha glucose where it is taken up my the vii of the small intestine |
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who are disaccharide digested? |
sucrose: contained within cells that needs to be broken down by the teeth to release it . the pancreatic juice is what breaks down sucrose into fructose and glucose by the enzyme sucrase Lactose: sugar found in milk . hence in yoghurt and cheeses . small intestine epithelial lining secretes lactase
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what is lactose intolerance? |
. lactose intolerance occurs in individuals that cannot produce the enzyme lactase by their small intestine . when undigested lactose reaches the large intestine bacteria break it down which gives rise to a large volume of gas . this may result in bloating, diarrhoea, nausea and cramp . the main difficulty is taking in sufficient calcium |
