1. Standards KNOW THIS

2. 6.1.1 Explain why digestion of large food molecules is essential  Food consumed contains unsuitable substances for human tissues Broken down and reassembled  Too large to be absorbed by villi Broken down to be absorbed through: 1. Diffusion 2. Facilitated diffusion 3. Active transport

3. 6.1.2 Explain the need for enzymes in digestion  Digestion of large molecules at body temperature occurs at a very slow rate  Enzymes speed up the process (E.g. saliva turns starch to maltose)

4. 6.1.3 State the source, substrate, products and optimum pH conditions for one amylase, one protease and one lipase AmylaseProteaseLipase Example Salivary amylasePepsinPancreatic lipase Source Salivary glands Wall of stomachPancreas SubstrateStarchProteins Triglycerides (fats or oils) ProductsMaltose Small polypepti des Fatty Acids and Glycerol Optimum pHpH 7pH 1.5pH 7

5. 6.1.4 Draw and label a diagram of the digestive system Disregard: 1.Pharynx 2.Rectum

6. 6.1.5 Outline the function of the stomach, small intestine and large intestine  Stomach Digestion of proteins  Catalyzed by pepsin Bacteria killed by acidity  Small Intestine Enzymes secreted through wall complete the process Products absorbed by villi on wall  Large Intestine Indigestible parts & large volumes of water  Water absorbed leaving feces  Egested through anus

7. 6.1.6 Distinguish between absorption and assimilation  Food taken into system through mouth and esophagus  ABSORPTION When food is passed through a layer of cells into the body’s tissues Occurs in small intestine  Villi absorb  ASSIMILATION: Absorbed food becomes a part of the tissues of the body

8. 6.1.7 Explain how the structure of the villus is related to its role in absorption and transport of the products of digestion  Increases surface area to absorb food Microvilli (protrusions on plasma membrane)  Epithelium (this layer of cells) is all that food must pass through  Protein channels in microvilli allow for fast absorption by facilitated diffusion by active transport  Mitochondria = ATP for active transport  Blood capillaries close to epithelium so less distance for diffusion  Lacteal carries away fats after absorption

9. 6.1.7 Explain how the structure of the villus is related to its role in absorption and transport of the products of digestion