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The process of digestion.

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Essay On Digestion Food gives us energy for the various activities that keep us alive. This food needs to be broken down so that it's small enough to pass into our blood. We have a long tube with many functions running from our mouth to our anus (bottom). This is called the digestive tract. Food is taken through the mouth to the stomach and into the small intestine where it is digested. Digestion is the complete breakdown of food so it can be absorbed and used by the body for energy. Digested food is absorbed into the blood stream. Food takes about 24 hours to digest. There are organs and glands producing digestive juices that help with digesting this food. The glands are the salivary (spit) glands, pancreas and liver. Digestion is like taking a house apart, brick by brick. The bricks are the smallest building blocks of the house. In the same way, nutrients are broken down too. Proteins are digested into amino acids, fats into glycerol and fatty acids and carbohydrates into simple sugars (glucose). The blood then carries these to the cells where they are needed. Food is digested in two ways, physically and chemically. There are special organs that chew, tear, churn, squeeze, mix and grind the food, e.g. ...read more.


Different enzymes act on different types of food groups and are therefore very specific. The names of enzymes usually end in -ase and are often named according to the substance on which they act. Experiment 1 Step 1 Make a thin paste of flour and water in a bowl until a white paste has been formed Step 2 Add a drop of iodine Step 3 The white paste turns blue-black where the iodine drops landed Step 4 Add a small amount of biological washing powder and mix together well Step 5 Set the mixture aside for 15 minutes Result The blue-black mixture will start going lighter and eventually turn brown, showing that starch is no longer present The students concluded that the mixture has starch in it because the white paste turned blue black when iodine was added. However when the washing liquid was added the colour changed again. This meant that the washing liquid obviously had enzymes in it to break down the starch. Experiment 2 Step 1 Cut a banana into pieces Step 2 Take one piece and put a few drops of iodine on it Step 3 The banana goes blue-black when iodine was added showing that starch is present Step 4 Now spit on the banana. ...read more.


Take note Megan cut an apple in half. One half she put on a plate and left on the kitchen counter. The other half she cooked in the microwave. She then placed the cooked half on the same plate and left them both for 1 hour. The pictures below show what the apples looked like after 1 hour: Uncooked apple Cooked apple Conclusion: The apple goes brown. It contains an enzyme, which turns the tissues brown when an apple is peeled and left for a time. Conclusion: The boiled apple does not go brown. Enzymes are sensitive to temperatures and were denatured when boiled. Glucose, fats and amino acids are carried in the blood to cells where they are needed. Carbohydrates - glucose Glucose is used in cellular respiration to provide energy. Energy is used for many activities. When there is more than the body needs it will store it as fat. Fats - fatty acids and glycerol Fats are used to make cell membranes, other structures and for energy. Any extra gets stored as fat. Proteins - Amino acids Amino acids are used to make new protoplasm during growth, enzymes and replacing old cells. Amino acids cannot be stored as fat so they are sent to the liver where they are broken down. Part of it is sent to the kidneys to be added to the urine while the remaining part is used for energy. ...read more.

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