Enzymes, digestion and metabolism - Intro

Leave a lump of starch in a dish at body temperature and almost nothing happens to it for days. Put the same starch in your mouth and it starts turning into sugars in minutes, with no flame, no acid bath and no waiting. The difference is enzymes. This is Enzymes, digestion and metabolism, for GCSE Biology: the words the rest of the subject leans on, then food broken down, built up and measured.

A handful of words carry this whole chapter, and four later chapters assume you already own them. The early videos set those words up, and the later ones put them to work on food.

How enzymes work is where to begin if enzymes are new to you, and it is for everybody. Common slips are confusing the enzyme with the substrate and writing killed instead of denatured, so this video keeps those words straight. What changes the rate of an enzyme-controlled reaction is the one to press if you know the words and graphs are the worry. Temperature, pH and concentration each get their own reason, and it clears up the idea, printed as a misconception by one course, that every enzyme works best at body temperature. The human digestive system: digestive enzymes and bile covers the organs, which enzyme is made where, and what bile does. Only some courses ask for it, so if yours does not print the digestive system, skip it and the next video still follows on perfectly. If yours does, the common slip is running together where an enzyme is made and where it works. Building and breaking down carbohydrates, proteins and lipids is for everybody, and it is where monomer and polymer get used properly. On one paper, the hardest question in its first section asked what small units build a carbohydrate. Measuring the energy in food by calorimetry is for separate biology only, so if you are on combined science, skip it. Some courses do not list it at all, but one of those has still set the calculation in a paper, so watch it if you have the time. Any video can be found by searching its name or its code, and the codes are on the list. The quickest route is the scholafly.com website, which indexes every video in every subject.

Next in the chapter is How enzymes work. Hopefully that's next in your feed, but if not, search for ScholaFly B I oh three, oh one.

Every other video is on scholafly.com too, easy to search by video code or by keyword. Whatever you're revising, go there and have a look, or, watch the next video.