Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
6.1 - Digestion I. Purpose of digestion A. Food is made of cells, and therefore macromolecules (carbs, lipids, proteins, nucleic acids) that your body needs to function B. Macromolecules are too big to cross cell membranes C. Your digestive system breaks polymers down into monomers so that they can get into your cells D. Your cells use the monomers to build macromolecules II. 4 steps A. Ingestion – eat B. Digestion – break down into smaller molecules C. Absorption – molecules move from digestive tract into blood and lymph D. Transport – circulatory system delivers molecules to cells III. Digestion is an enzyme-driven process A. Digestive enzymes catalyze hydrolysis reactions – hold macromolecules in place and stress bonds until body heat causes them to break Salivary Amylase Pepsin Trypsin Pancreatic Lipase Pancreatic Amylase Source Salivary Glands Stomach cells Pancreas Pancreas Pancreas Location of action Mouth stomach Small intestine Small Intestine Small Intestine Substrate Amylose (starch) proteins proteins lipids Amylose (starch) Product maltose, glycerol and amino acids amino acids glucose fatty acids pH 7 pH 3 8 8 maltose, glucose 8 IV. Absorption A. Villi – finger-like projections that line the small intestine – increase surface area! 1. Contain a capillary network for nutrients to pass into the blood (carbs and proteins) and a lacteal for the lymph system (lipids) B. Passive Transport 1. Simple diffusion - fatty acids 2. Facilitated diffusion – glucose, amino acids C. Active Transport 1. Pumps – glucose, amino acids 2. Endocytosis – not fully digested macromolecules V. Importance of smooth muscle A. Longitudinal – moves food through B. Circular – mechanical digestion