https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/properties-uses-of-plastic 2026-04-29T07:20:45.495372596Z Properties & uses of plastic Properties & uses of plastic Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Properties & uses of plastic Properties & uses of plastic https://cdn.kastatic.org/ka-youtube-converted/31TAMsgHSog.mp4/31TAMsgHSog.mp4 365 Polymers https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/rayon-nylon-polyester-acrylic 2026-04-29T07:20:45.495372596Z Rayon Nylon Polyester & Acrylic Rayon Nylon Polyester & Acrylic Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Rayon Nylon Polyester & Acrylic Rayon Nylon Polyester & Acrylic https://cdn.kastatic.org/ka-youtube-converted/9uctOGRUHgA.mp4/9uctOGRUHgA.mp4 438 Polymers https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/introduction-to-polymers-synthetic-fibers 2026-04-29T07:20:45.495372596Z Introduction to Polymers & Synthetic Fibers Introduction to Polymers & Synthetic Fibers Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Introduction to Polymers & Synthetic Fibers Introduction to Polymers & Synthetic Fibers https://cdn.kastatic.org/ka-youtube-converted/HFjt2VAbOzc.mp4/HFjt2VAbOzc.mp4 306 Polymers https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/introduction-to-synthetic-fibers-and-polymers 2026-04-07T22:23:57.656416987Z Introduction to synthetic fibers and polymers Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/ap-biology/chemistry-of-life/introduction-to-biological-macromolecules/a/introduction-to-macromolecules 2021-04-29T07:53:30Z Introduction to macromolecules Types of large biological molecules. Monomers, polymers, dehydration synthesis, and hydrolysis. article https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/rayon-nylon-polyester-acrylic 2026-04-07T23:36:17.218592739Z Rayon Nylon Polyester Acrylic Lets answer some questions Shankar R exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/how-are-plastics-made-pk 2025-12-18T18:40:53.641757593Z How are plastics made? Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw How are plastics made? Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/3IpmaxV1tiY.mp4/3IpmaxV1tiY.mp4 227 Polymers https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/types-of-polymerisation-reactions 2026-03-18T14:20:48.260499955Z Types of polymerisation reactions To analyze reactions to identify the type of polymerisation (addition, condensation, copolymerisation). Swarnendu Koner exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/plastics-types-of-plastics-pk 2025-12-18T18:40:53.641757593Z Plastics & Types of Plastics Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Plastics & Types of Plastics Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/YKYvFDkHNRA.mp4/YKYvFDkHNRA.mp4 385 Polymers https://www.khanacademy.org/science/cambridge-o-level-biology-cie/x2a084a90105205d2:relationships-of-organisms-with-one-another-and-with-the-environment/x2a084a90105205d2:effects-of-humans-on-ecosystems/v/plastics-and-environment-pk 2025-12-18T18:40:53.641757593Z Plastics and environment Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Plastics and environment Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/ZAAzbw_ei9Q.mp4/ZAAzbw_ei9Q.mp4 358 Polymers https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:intermolecular-forces-and-properties/x2eef969c74e0d802:solids-liquids-and-gases/v/crystalline-and-amorphous-polymers 2022-10-05T02:43:18.611402953Z Crystalline and amorphous polymers Polymers can exist as both crystalline and amorphous solids. In fact, most polymers are semicrystalline, which means that they contain a mixture of crystalline and amorphous regions. In this video, we'll see different examples of semicrystalline and amorphous polymers and learn how their structures can be represented using particulate models. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/eeff6706-f255-46df-9f52-3204fdaf6d1f_1280_720_base.png Crystalline and amorphous polymers Polymers can exist as both crystalline and amorphous solids. In fact, most polymers are semicrystalline, which means that they contain a mixture of crystalline and amorphous regions. In this video, we'll see different examples of semicrystalline and amorphous polymers and learn how their structures can be represented using particulate models. https://cdn.kastatic.org/ka-youtube-converted/p5mXv39n9GM.mp4/p5mXv39n9GM.mp4 282 Polymers https://www.khanacademy.org/science/cambridge-o-level-biology-cie/x2a084a90105205d2:relationships-of-organisms-with-one-another-and-with-the-environment/x2a084a90105205d2:effects-of-humans-on-ecosystems/e/plastic-and-environment 2026-04-10T11:50:42.031414522Z Plastic and environment Lets answer some questions Shankar R exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/responsible-use-of-plastics 2025-08-05T18:56:35.058002345Z Responsible use of plastics. An exercise on the responsible use of plastics for middle school students. Joel Prakash Stephen exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/rubber 2026-03-18T14:20:48.260499955Z Rubber To apply knowledge of rubber chemistry to compare natural and synthetic varieties and analyze their uses. Swarnendu Koner exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/e/properties-and-uses-of-plastics 2026-04-07T23:17:37.123726494Z Properties and uses of Plastics Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/peptide-bond-formation-and-cleavage 2023-08-11T20:27:11.407186761Z Peptide bonds: Formation and cleavage Peptide bonds are the vital links that connect amino acids to form polypeptide chains, which fold into functional proteins. These bonds are formed through a nucleophilic addition-elimination reaction and are characterized by their rigidity and planarity, thanks to resonance delocalization. The process of breaking these bonds is called hydrolysis, which can be nonspecific with strong acids or specific with proteolytic enzymes. By Tracy Kovach. Tracy Kim Kovach video https://cdn.kastatic.org/googleusercontent/DPDltlvVPiC4ObaQqHJSfb3_jt9nthyOR_F4c344csZ3FN59dwCBAXABFHrZOyOSaBalpxCDFK5WzidAoZAvIBl3 Peptide bonds: Formation and cleavage Peptide bonds are the vital links that connect amino acids to form polypeptide chains, which fold into functional proteins. These bonds are formed through a nucleophilic addition-elimination reaction and are characterized by their rigidity and planarity, thanks to resonance delocalization. The process of breaking these bonds is called hydrolysis, which can be nonspecific with strong acids or specific with proteolytic enzymes. By Tracy Kovach. https://cdn.kastatic.org/ka-youtube-converted/pmQuNRHJMw4.mp4/pmQuNRHJMw4.mp4 431 Polymers https://www.khanacademy.org/science/biology/macromolecules/proteins-and-amino-acids/a/introduction-to-proteins-and-amino-acids 2021-04-29T07:56:49Z Introduction to proteins and amino acids Different types of proteins. The structure and properties of amino acids. Formation of peptide bonds. article https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:energy-and-matter-in-biological-systems/x230b3ff252126bb6:biomolecules-and-reactions/v/introduction-to-proteins-and-amino-acids 2023-09-14T11:07:34.466749579Z Introduction to proteins and amino acids Proteins, large biomolecules or macromolecules, play a vital role in almost every biological process. They are made up of chains of amino acids, which are their building blocks. These chains, known as polypeptides, can form complex shapes, contributing to the diverse functions of proteins. Proteins can provide structure, facilitate muscle contraction, catalyze reactions as enzymes, and participate in immune response and signaling. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/7d140eef-7cac-45a0-9370-f705e69d9d10_1280_720_base.png Introduction to proteins and amino acids Proteins, large biomolecules or macromolecules, play a vital role in almost every biological process. They are made up of chains of amino acids, which are their building blocks. These chains, known as polypeptides, can form complex shapes, contributing to the diverse functions of proteins. Proteins can provide structure, facilitate muscle contraction, catalyze reactions as enzymes, and participate in immune response and signaling. https://cdn.kastatic.org/ka-youtube-converted/78QUeXVKiJ4.mp4/78QUeXVKiJ4.mp4 353 Polymers https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/v/amino-acid-structure 2022-11-16T04:22:43.7414897Z Amino acid structure Amino acids are the building blocks of proteins. They contain an amino group, carboxylic acid group, alpha carbon, and side chain. Most amino acids have a chiral carbon, which allows them to rotate polarized light. Amino acids can have either an L- or D- configuration, but only the L- form is found in the human body. Tracy Kim Kovach video https://cdn.kastatic.org/googleusercontent/J-5_j1Rdry3Fg-JF4qL6XloVOPvQ161fiRNoQUNJeng-4VcANvJuIRRmnGG8en3CizzxRvMvu43rI6UFeHfzN-Qq6Q Amino acid structure Amino acids are the building blocks of proteins. They contain an amino group, carboxylic acid group, alpha carbon, and side chain. Most amino acids have a chiral carbon, which allows them to rotate polarized light. Amino acids can have either an L- or D- configuration, but only the L- form is found in the human body. https://cdn.kastatic.org/ka-youtube-converted/BbZB-WBVFSk.mp4/BbZB-WBVFSk.mp4 655 Polymers https://www.khanacademy.org/science/biology/macromolecules/proteins-and-amino-acids/a/orders-of-protein-structure 2025-05-22T06:48:27.648113164Z Orders of protein structure Orders of protein structure: primary, secondary, tertiary, and quaternary. Alpha helix and beta pleated sheet. article https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:organic-chemistry/x8bc8fb44369617ed:polymers/a/amino-acid-structure-and-classifications 2024-10-08T13:00:40.553432776Z Amino acid structure and classifications This article reviews the 20 proteinogenic amino acids, their structures, symbols, and abbreviations, and related information important for the MCAT. article https://www.khanacademy.org/science/biology/macromolecules/proteins-and-amino-acids/v/peptide-bond-formation 2021-03-18T10:33:23Z Peptide bond formation How amino acids form peptide bonds (peptide linkages) through a condensation reaction (dehydration synthesis). video https://cdn.kastatic.org/googleusercontent/NTglMUp85MtJs8VhqDdR7MKpsF0ZnK9NxwB7LFjiw6C_nQTgU_OJ0KigMM9DMep7K38LdrGRspQQJbp_SUlwqEqZNQ Peptide bond formation How amino acids form peptide bonds (peptide linkages) through a condensation reaction (dehydration synthesis). https://cdn.kastatic.org/ka-youtube-converted/nv2kfBFkv4s.mp4/nv2kfBFkv4s.mp4 506 Polymers