ABSORPTION of NUTRIENTS Digestive System Warm-up • What happens to food after you eat it? • Name the biomolecules (carbohydrates, proteins, lipids) you think are in this food. Engage • Time to Chew! Explore • Digestion Animation – What happens at each step in Digestion? Digestion Notes • The function of the digestive system is to convert food into smaller molecules that can be used by cells. • Digestion begins in the MOUTH – Teeth tear food apart – The Enzyme AMYLASE begins to break down carbohydrates (starch). Enzymes are proteins • Each enzyme is the specific helper to a specific reaction – each enzyme needs to be the right shape for the job – enzymes are named for the reaction they help Oh, I get it! They end in -ase • • • • sucrase breaks down sucrose proteases breakdown proteins lipases breakdown lipids DNA polymerase builds DNA s6 Enzymes aren’t used up • Enzymes are not changed by the reaction – used only temporarily – re-used again for the same reaction with other molecules – Enzymes work by speeding up the rate of a reaction (lowering the activation energy) substrate active site product enzyme It’s shape that matters! • Lock & Key model – shape of protein allows enzyme & substrate to fit – specific enzyme for each specific reaction • The food (bolus) passes down your ESOPHAGUS by peristalsis to your STOMACH. – In the stomach, HYDROCHLORIC ACID helps to break down food. – The enzyme PEPSIN starts to break down proteins. • The mixture leaving your stomach is called CHYME. • The chyme moves into the SMALL INTESTINE. – Most of the chemical digestion and absorption of nutrients occurs here. • Amylase breaks down starch • Trypsin breaks down protein • Lipase breaks down fat – Your PANCREAS produces these enzymes. Small Intestine • Your liver releases BILE into the small intestine which helps in fat digestion. Small Intestine - Villi • VILLI in your small intestine are fingerlike projections made of connective tissue that absorb nutrients into your bloodstream. Large Intestine • The chyme now moves to the LARGE INTESTINE, where water is removed. • Microorganisms (probiotics) help maintain the health of the large intestine by reducing the growth of harmful bacteria Removal • After water has been removed, the waste moves through the rectum and out of the body through the anus. • Large Intestine is an organ that functions in both digestive and excretory system Excretory System • Animals produce waste products that must be removed from their body. • Most animals have a system that deals with nitrogen-rich wastes from the breakdown of proteins and nucleic acids. • Ammonia (NH3) is toxic. • In addition, it helps maintain homeostasis – balancing osmotic action and pH. Urinary System Circulatory System • Humans and other vertebrates have a closed circulatory system Heart • Composed of muscle • The right and left sides of the heart are separated by a septum (prevents the mixing of oxygen rich and oxygen poor blood) Blood Vessels • 3 types – Artery: carry oxygen rich blood from heart to tissue. Thick walled due to pressure.. – Capillary: smallest blood vessels (one cell thick. Important for bringing nutrients and oxygen to tissues and absorbing CO2 and other waste products. – Vein: returns oxygen poor blood to heart. Contains valves for one way flow. Organs • Esophagus- food tube connecting mouth to the stomach. • Stomach- continues digestion of food. Hydrochloric Acid helps in this process. • Small Intestine- Most of the absorption of nutrients happen here. • Large Intestine- Leads waste to the rectum. Water is absorbed here. • Rectum- Holding area for feces. • Anus- opening where wastes leave the body. • Liver- cleans the blood by filtering poisons and wastes. • Gallbladder- aids the breakdown of fats. • Pancreas- located behind the stomach. Produce hormones (insulin) that regulate blood sugar levels. Produces enzymes that help with digestion. Elaborate/Evaluate-Draw and Describe • Name the biomolecules contained in this cheeseburger. • Describe how the cheeseburger is digested from the mouth to the large intestine. Include enzymes that break down each biomolecule in the different organs.