in this video we're going to look at how the different biological molecules that we eat like carbohydrates proteins and lipids are broken down by enzymes into smaller soluble molecules that we can absorb so the first question really is why do we need to do this why do we need to break everything down basically the carbohydrates proteins and lipids that we eat in our diet are normally pretty big molecules and so they're way too big for us to absorb into our bloodstream across the Villi of our small intestine instead they have to be broken down first into much smaller pieces and for that we need enzymes which remember are special proteins that can speed up the rate of chemical reactions so the point of this video is to explain which smaller molecules each food group is broken down into and which specific enzymes are used if we start with carbohydrates most of the carbohydrates that we eat from foods like pasta and potatoes are in the form of starch and starch is a polymer of glucose so it's a really long molecule made up of loads of glucose molecules where which in this case we can call the monomers in order to break the starch down we first use the enzyme amales which breaks it into molos molecules these are basically just two glucose molecules stuck together and then the enzyme moles breaks the molos down into glucose which is now small enough for us to absorb something you might have noticed here is that both of our enzymes amalay and mores end in a and this is pretty common among enzymes so it's worth remembering moving on to proteins these are found in foods like meat and nuts and they're broken down by protease enzymes into amino acids it's worth knowing that there are lots of different types of amino acids but they're all pretty similar and you don't need to know what the differences between them are also the term proteas refers to a whole group of enzymes which include specific enzymes like Trin and pepsin lastly we have lipids which refer to both fats and oils so these are found in things like avocados and olive oil in either case though they're broken down by lipase enzymes into smaller molecules called glycerol and fatty acids another thing to mention here is bile bile isn't an enzyme but it does help in the breakdown of lipids because it emulsifies them this means that it can take big droplets of lipid and break them up into lots of little droplets and this is really helpful because it increases the surface area for the lipase enzymes to break the lipids down properly now before we finish as well as knowing which enzyme does what you also need to know where each of the enzymes are made the simplest way to remember it is that all three types of enzymes are made by both the pancreas and by the small intestine then amales is also made by the salivary glands in the mouth and proteases are also made by the stomach if you haven't heard yet you can find all of our videos on our website cognito org you'll also find questions flashcards exam style questions and pass papers and we track all of your progress so that you always know what to study next so sign up for free by clicking here or browse our playlist here on YouTube