Hi, this is Mr. W from ScienceMusicVideos.com, and this video is about monomers and polymers. Big biological molecules like DNA are built from smaller building blocks called monomers. Let's look at a big molecule that we eat a lot of, starch.
Here it is. Notice this repeating unit. It's glucose, and you can see that starch is just one glucose chained to the next over and over again. That makes glucose the monomer, while starch is a polymer, a molecule composed of linked monomers. To remember this, use the prefixes.
Mono means one, as in monorail. Poly means many, as in polygon. Think about it in terms of Legos.
Individual Lego bricks, those are monomers. The structures you build by putting Legos together. Those are polymers. All life is built from a relatively small number of monomers that combine into an astoundingly large number of polymers. Just think of our own bodies with a variety of proteins like muscle or oxygen carrying hemoglobin or thousands of enzymes and millions of antibodies.
We build all of these from 20 protein monomers called amino acids. It's just like the alphabet of any language like English. You can take 26 letters, which are like monomers, and combine them into hundreds of thousands of words, which are like polymers.
In cells, protein catalysts called enzymes take monomers and chemically link them together. It's called dehydration synthesis. The enzyme pulls an H, a hydrogen, from one monomer and an OH, a hydroxyl, from the other monomer and links them together at that point. The H and OH combine to form a molecule of water.
That's why it's called dehydration synthesis. Here's a sweet example. Here are two carbohydrate monomers, glucose and fructose. Through a dehydration synthesis reaction, they combine to form sucrose or table sugar.
Organisms also need to be able to break polymers apart. It's a big part of what happens during digestion. Enzymes break the bonds between monomers by jamming a water molecule in between them. It's called hydrolysis, splitting with water. Of course, Monomers can be further broken down.
Later on in this course, we'll look at cellular respiration, in which cells take glucose and break it down all the way to carbon dioxide and water, as cells make ATP. In addition, monomers have to be made. Later on, we'll see how during photosynthesis, chloroplasts can take carbon dioxide and water and combine them to form glucose, which in terms of matter and energy, is the starting point for just about everything else.
So that's it for monomers and polymers. Right now, go to sciencemusicvideos.com, where there's a tutorial waiting for you that'll help you master this material and master many other topics in biology. Please subscribe to my website, subscribe to my channel, and if you're part of a class that's not using Science Music Videos, tell your instructor about it, and please encourage them to contact me to talk about setting up a site license. Thank you so much for joining me.
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