digestion of starch by salivary amylase
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Amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion. ...
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Answers:An Amylase is an enzyme that chemically breaks big starch molecules into smaller molecules. This break down process is called chemical digestion or more technically , hydrolysis. The substance that is being broken down (digested/hydrolysed) is called the substrate. In your question, starch would be the substrate and amylase is the enzyme. There are different kinds of amylases (an enzyme that digests starch). The kind of amylase that is found in saliva is called ptyalin. Now, to answer your question: The starch molecule is a big molecule. It is called a polysaccharide. The enzyme ptyalin digests (hydrolysis) or breaks down the polysaccharide molecule starch into two smaller molecules called maltose. Technically, maltose is called a disaccharide. Summary: 1Starch (polysaccharide)molecule + some water (+ ptyalin)------->2 maltose (disaccharide) molecules. All this occurs in your mouth as you chew starchy foods like bread, potatoes or rice. By the way, you put this question in the wrong YA section . This is not a "botany" question and should have been asked in "biology."
Answers:There are two types of amylase in the body - salivary amylase and pancreatic amylase. Salivary amylase is an enzyme present in saliva, and acts when saliva is secreted in the mouth during eating. Carbohydrates make up large portions of what we eat. Roughly two thirds of these ingested carbohydrates are made up of the polysaccharide, starch. Salivary amylase acts on the starch, partially digesting it. The enzyme's action is the beginning of chemical process of digestion. Salivary amylase is also present in the stomach, where it further digests the starch, until the enzyme is destroyed by gastric acid and digestion is continued in the small intestine, by pancreatic amylase. Both the amylase enzymes break down the starch into disaccharide sugars, mostly dextrose, maltose and maltotriose. These are then broken down further by enzymes contained within the intestinal epithelial cells, into monosaccharides such as glucose, fructose and galactose. Finally, the monosaccharides are transported across the intestinal epithelium into the bloodstream. --- As for designing your experiment: Make up a number of different food samples 1. Obtain say, 10 different food types (potatos, yoghurt, apple), trying to represent the spectrum of 'food groups', based on what you presume they contain (amount of proteins, carbohydrates, etc) 2. Weigh pieces of them out to a consistent amount, say, 1g. 3. Using mortar and pestle, grind the samples into a paste. 4. Filter pastes to remove solids, extracting liquids into beakers. 5. Transfer each sample to labelled test tubes. Testing amylase activity 1. Place 1mL of each food extract into each of ten test tubes. 2. Place 1mL of 0.05% starch solution into a test tube. Label as the 'blank'. 3. Place a drop of iodine into each test tube. 4. Place 1mL of amylase solution into each test tube. Notice some tubes will turn blue, as a complex forms between the iodine and starch present in the food extracts. 5. Note that where no blue colour appears, these foods contain no starch. 6. Wait an hour for the enzyme to react. 7. Place the blank test tube into a spectrophotometer. Mark the absorbance reading. This is to calibrate the 'zero point', by which all other readings will be determined. That is, other measurements are relative to this one (this is the absorbance when a known quantity of starch is placed in the machine). 8. Place the other tubes into the spectrophotometer, one by one. Mark the absorbance readings at intervals of say, once a minute for ten minutes. 9. Graph results, absorbance vs time. This will show enzyme activity. Notice the trends. Absorbance is proportional to amylase concentration. On your graph, you'll see absorbance values becoming lower for different foods, and at different rates. So you can use this graph to determine the rate of amylase activity on various food sources. The faster the rate of the reaction, the quicker the rate of starch breakdown. (Remember that because substrates can inhibit enzyme activity when the substrate concentration is high enough to block all the enzyme's binding sites, this experiment doesn't tell us how much starch is in each food sample. But since we know what food each sample is, we can determine the rate that it is broken down by amylase. From this we can conclude that the faster the food is broken down, the more quickly it will be absorbed across the intestinal epithelium.
Answers:Every enzyme has it own pH optimum. The amylase in the saliva has a pH optimum of 5.6. In the stomach, the pH is 1-2. So amylase stops working in the stomach. In the small intestine, a mixture of pancreatic enzymes work there: trypsin, chymotrypsin, lipase, amylase, etc.
Answers:The pancreas produces a hormone, glucagen, to stimulate a release of stored glycogen from the liver, in the form of glucose, into the blood to restore balance. FOR The mechanism of carbohydrase action. 5. Action of human salivary -amylase on amylopectin and glycogen,please visit: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1204700