Unit 6: Human Health And Physiology Lesson 6.1 Digestion

6.1.1 Explain why digestion of large food molecules is essential. Large food molecules are polymers, which must be broken down into monomers (via hydrolysis) in order to be absorbed into the blood.

6.1.2 Explain the need for enzymes in digestion. Enzymes speed up the rate at which polymers are broken down into monomers.

6.1.3 State the source, substrate, product and optimum pH conditons for one amylase, one protease and one lipase. AmylaseProteaseLipase Example of this enzyme Salivary amylase PepsinPancreatic lipase SourceSalivary glandsWall of stomach Pancreas SubstrateStarchProteinsTriglycerides (fats and oils) ProductMaltoseSmall polypeptides Fatty acids and glycerol Optimum pH

6.1.4 Draw a diagram of the digestive system. Locate: mouth, esophagus, stomach, small intestine, large intestine, anus, liver, pancreas, gall bladder.

6.1.5 Outline the function of the stomach, small intestine and large intestine. Stomach- primary site for protein digestion. Small intestine- primary site for overall nutrient absorption. Large intestine- water used in the digestive process is reabsorbed back into the body.

6.1.6 Distinguish between absorption and assimilation. Absorption- the transfer of nutrients from the digestive tract into the blood stream, usually through villi in the small intestine. Assimilation- uptake of nutrients from blood stream into body tissue. Occurs after absorption. Pictured: microvilli on a villus.

6.1.7 Explain how the structure of the villus is related to its role in absorption of the end products of digestion. Villi have a large surface area, gated ion channels, and are dense in mitochondria, which provide energy for the active transport of nutrients.