How Do Enzymes Works? An enzyme & Substrate are in the same area The enzyme grabs onto the substrate The chemical reaction happens The enzyme lets go When the enzyme lets go, it returns to normal, ready to do another reaction The substrate is now called the product

Salivary Amylase (starch) Some Examples of digestive enzymes: Salivary Amylase (starch) Mucus Bile (fats) Pepsinogen

Can You Stop Them? There are many factors that can regulate enzyme activity: 1) Temperature Increasing temperatures: increases how fast the reaction happens (more energy) Decreasing temperatures: decreases the rate of the reaction ( less energy)  2) pH Levels pH around 6-8 for most human enzymes Except stomach, Pepsin needs low pH (higher acidity) 3) Inhibitors Molecules that bind to the enzyme in some way to prevent the reaction from happening Slow down the reaction

ABSORPTION There are 2 types of absorption that occur in the digestive system. Absorption of nutrients: the small molecular end-products of digestion, as well as vitamins, minerals and water: which occurs in the small intestine Absorption of the large quantities of water: that is part of the leftover food/waste material which occurs in the large intestine.

Absorption in the Large Intestine “Leftovers” (undigested food) from the SI enter the LI through the ileocaecal sphincter. There are 3 sections: ascending colon transverse colon descending colon. The main function of the LI/colon is to re-absorb water from the leftover food. This is an effort to conserve water and compact the now “waste” material

Absorption in the Large Intestine Once water has been absorbed, the leftover waste can be stored in the lowest and last portion of the LI, called the rectum. Waste food materials are called FECES. Feces are excreted from the rectum through the anal sphincter (anus) by a process known as defecation.