1 00:00:01,356 --> 00:00:03,646 - [Voiceover] Proteins are gonna be the third 2 00:00:03,646 --> 00:00:05,906 of the major macromolecules. 3 00:00:05,906 --> 00:00:10,561 Now proteins are long chains of small subunits. 4 00:00:10,561 --> 00:00:14,061 These individual subunits are amino acids. 5 00:00:15,134 --> 00:00:19,195 What happens is, you can take multiple amino acids 6 00:00:19,195 --> 00:00:21,488 and bond them together, 7 00:00:21,488 --> 00:00:25,238 making long chains which can create proteins. 8 00:00:26,552 --> 00:00:30,135 In total, there's 20 different amino acids, 9 00:00:31,587 --> 00:00:34,127 so really that's not very many. 10 00:00:34,127 --> 00:00:38,923 It all depends on how these amino acids are ordered. 11 00:00:38,923 --> 00:00:41,204 You can create multiple different orders 12 00:00:41,204 --> 00:00:44,474 to create many different proteins. 13 00:00:44,474 --> 00:00:48,305 Now these amino acids all share some common traits. 14 00:00:48,305 --> 00:00:51,138 Every amino acid has an amino end. 15 00:00:53,727 --> 00:00:55,949 Well, that's your nitrogen side, 16 00:00:55,949 --> 00:00:59,153 so you have nitrogen on the amino side. 17 00:00:59,153 --> 00:01:01,711 Then you have your carboxyl end. 18 00:01:01,711 --> 00:01:06,500 That's carbon double-bonded to an oxygen and then 0H. 19 00:01:06,500 --> 00:01:08,949 And you have this R group. 20 00:01:08,949 --> 00:01:12,783 The R group is referred to as the radical group. 21 00:01:12,783 --> 00:01:15,033 That is the only difference 22 00:01:16,280 --> 00:01:18,363 among all 20 amino acids. 23 00:01:19,640 --> 00:01:22,544 They all have the exact same amino end, 24 00:01:22,544 --> 00:01:25,702 the exact same carboxyl end, 25 00:01:25,702 --> 00:01:28,185 but their R group will vary, 26 00:01:28,185 --> 00:01:31,230 and that's what creates the differences. 27 00:01:31,230 --> 00:01:32,268 Now these amino acids, 28 00:01:32,268 --> 00:01:36,486 they're all joined together by peptide bonds. 29 00:01:36,486 --> 00:01:39,281 So we know that your lipids were bound together, 30 00:01:39,281 --> 00:01:42,591 we know that the carbohydrates were bound together, 31 00:01:42,591 --> 00:01:45,791 but the bonds here have a special name. 32 00:01:45,791 --> 00:01:49,958 So proteins are made from the building blocks amino acids, 33 00:01:50,928 --> 00:01:54,807 which are held together by peptide bonds. 34 00:01:54,807 --> 00:01:58,470 These peptide bonds, look at that, 35 00:01:58,470 --> 00:02:01,970 they're produced by dehydration synthesis. 36 00:02:02,851 --> 00:02:06,230 That means carbohydrates, lipids, and now proteins 37 00:02:06,230 --> 00:02:09,868 all use this dehydration synthesis. 38 00:02:09,868 --> 00:02:12,201 Remove water to make a bond. 39 00:02:15,304 --> 00:02:18,437 So here are some of those amino acids. 40 00:02:18,437 --> 00:02:20,689 Now if you kind of look and you go through 41 00:02:20,689 --> 00:02:22,923 the non-highlighted portions, 42 00:02:22,923 --> 00:02:25,037 you can see they're all C. 43 00:02:25,037 --> 00:02:27,019 Then you have a bond of CO negative, 44 00:02:27,019 --> 00:02:28,519 an NH3 plus, an H, 45 00:02:29,675 --> 00:02:32,038 but the highlighted group, 46 00:02:32,038 --> 00:02:34,560 that's the difference. 47 00:02:34,560 --> 00:02:37,224 The highlighted group is what changes 48 00:02:37,224 --> 00:02:39,724 from amino acid to amino acid, 49 00:02:41,162 --> 00:02:44,580 because the actual base structure is always the same. 50 00:02:44,580 --> 00:02:47,579 It just changes based on that R group. 51 00:02:47,579 --> 00:02:50,960 And all these highlights are the R groups. 52 00:02:50,960 --> 00:02:53,392 They can be as simple as glycine, 53 00:02:53,392 --> 00:02:56,106 which is gonna be found on the right hand side. 54 00:02:56,106 --> 00:02:58,523 It's the fourth one down. 55 00:02:58,523 --> 00:03:00,780 So just a simple H, that's it. 56 00:03:00,780 --> 00:03:03,473 Nice and basic and simple. 57 00:03:03,473 --> 00:03:06,898 Or it can get as complicated as tryptophan. 58 00:03:06,898 --> 00:03:09,981 That's on the left hand side four up. 59 00:03:11,068 --> 00:03:13,542 You can see how that tryptophan has a whole ring, 60 00:03:13,542 --> 00:03:14,676 then a bunch of other stuff. 61 00:03:14,676 --> 00:03:17,593 That's a really complex amino acid. 62 00:03:18,785 --> 00:03:20,499 More as a side note, have you ever heard of tryptophan, 63 00:03:20,499 --> 00:03:23,170 maybe while making turkey at Thanksgiving? 64 00:03:23,170 --> 00:03:24,053 Tryptophan is that stuff 65 00:03:24,053 --> 00:03:25,277 that's in the turkey at Thanksgiving 66 00:03:25,277 --> 00:03:28,156 that is naturally there, no problem there, 67 00:03:28,156 --> 00:03:29,172 that's what makes you kind of tired, 68 00:03:29,172 --> 00:03:30,688 a little drowsy there. 69 00:03:30,688 --> 00:03:32,408 They have a lot of tryptophan. 70 00:03:32,408 --> 00:03:35,715 Urge the body to take a rest, to take a nap. 71 00:03:35,715 --> 00:03:39,455 So tryptophan, a little trivia there. 72 00:03:39,455 --> 00:03:43,868 So here are how the amino acids are put together. 73 00:03:43,868 --> 00:03:48,768 You see we have isoleucine and alanine are already bound, 74 00:03:48,768 --> 00:03:51,180 but to create a longer chain, 75 00:03:51,180 --> 00:03:55,721 the example here showing that valine needs to be added. 76 00:03:55,721 --> 00:03:59,105 Well, to add valine, you'd better take off some water. 77 00:03:59,105 --> 00:04:01,976 Two hydrogen and an oxygen are pulled off, 78 00:04:01,976 --> 00:04:04,878 leaving the ability to bind, 79 00:04:04,878 --> 00:04:06,795 forming a peptide bond. 80 00:04:09,284 --> 00:04:13,102 And this'll keep happening over and over and over. 81 00:04:13,102 --> 00:04:15,180 You just keep adding one after another 82 00:04:15,180 --> 00:04:19,930 after another amino acid until the chain is long enough 83 00:04:19,930 --> 00:04:23,847 to be the proper length to form into a protein. 84 00:04:24,748 --> 00:04:27,208 So the only way to get a protein 85 00:04:27,208 --> 00:04:29,458 is to have enough amino acids 86 00:04:29,458 --> 00:04:32,398 put together in the proper order 87 00:04:32,398 --> 00:04:35,126 to make a long enough polypeptide. 88 00:04:35,126 --> 00:04:39,406 Polypeptides are just chains of amino acids. 89 00:04:39,406 --> 00:04:43,489 Make a long enough polypeptide to form a protein.