Topic Five (1.5): Bacteria and enzymes in digestion

Objectives

By the end of this topic you should be able to:

describe the role of enzymes in digestion
describe the role of bacteria in digestion.

Introduction

In this topic, you will learn how digestion (the breakdown of large (insoluble) molecules into small (soluble) molecules so that they can pass into the bloodstream) relies on bacteria and enzymes. Enzymes are very important in Biology, as well as being really useful and amazing.

Working through your coursebook

VIEW - Resource 1: Food for Thought PowerPoint (slides 14-18) Download VIEW - Resource 1: Food for Thought PowerPoint (slides 14-18)

Read pages 32–33 of your coursebook. Not all bacteria are bad! Make sure that you know the importance of bacteria in the intestines and understand what the word ‘probiotic’ means.
Next watch this video on bacteria in digestion:

Enzymes speed up digestion. Remember that carbohydrase breaks starch down into sugar (keep a piece of bread in your mouth for long enough and it begins to taste sweet), protease breaks down protein into amino acids and lipase breaks down lipids/fats into fatty acids and glycerol.
If you would like to, you can make a model digestive system by following the Gross Science project below. Be careful not to make too much mess! (Scroll down the page - to the instructions)

COMPLETE - The Ultimate Gross Science Project (hubpages.com) Links to an external site.