Why do beans make you fart?
Welcome to the very first issue. The short answer is: it's not you, it's your bacteria. This fortnight's Short follows one sugar from a bowl of beans all the way to the gas, and it doubles as a neat enzyme-specificity hook for your classes. Below that, AI marking arrives in the exam maker, and there are three new free simulators.
Beans, bacteria and the gas
Raffinose slips past human enzymes, reaches the large intestine, and gets fermented. 34 seconds, zero shame.
Watch the ShortThe biology, and where it fits
Beans are rich in raffinose, a trisaccharide of galactose, glucose and fructose. Hydrolysing it needs the enzyme α-galactosidase, which we don't secrete into the gut, so raffinose reaches the large intestine intact. There, bacteria ferment it anaerobically, releasing hydrogen and carbon dioxide. In some people, archaea turn part of that into methane.
IB Biology: B1.1 Carbohydrates and lipids (hydrolysis of glycosidic bonds), C1.1 Enzymes and metabolism (specificity and the active site), C1.2 Cell respiration (anaerobic respiration, with bacterial fermentation as a comparison).
AP Biology: Topic 1.3 (hydrolysis), Topic 3.1 Enzyme Structure (specificity), Topic 3.6 Cellular Respiration (fermentation).
Try it as a starter: ask the class why we can't digest raffinose before playing the Short.
- The exam maker now marks papers with AI
The first 200 people to sign up get 10 free credits: enough for ten practice papers, or two drafts through the IA marker for moderation or student feedback. Tell your students!
- New simulators: transects, quadrats and cell signalling
All free, all on the labs page. Is there a simulator you wish existed? Hit reply and tell me.
Rainy Day Biology: free sampler
Try a few of the print-and-play activities from Book 1 before buying: dominoes, jigsaws and more, each with a teacher key. Perfect for the lesson where the plan goes out the window.
Get the free samplerRainy Day Biology, Book 1: Molecules & Cells from $19
21 activities in 8 game formats, from dominoes to Double Agents, each with a teacher key. Buying the first edition directly supports the site. Books 2 and 3 are being put together now and are coming soon.
Preview & buySee you in a fortnight,
Adam
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