Polymers-CentralLyonCSD：93聚合物-里昂CSD中央

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1、9.3 PolymersCouplers that interlock connect one railroad car to another. Many cars can be joined together to form a train, because there are couplers on both ends of a car. 9.3 PolymersA polymer is a large molecule that forms when many smaller molecules are linked together by covalent bonds. The sma

2、ller molecules that join together to form a polymer are monomers. In some polymers, there is only one type of monomer. Other polymers have two or more kinds of monomers. 9.3 PolymersWhat is one way that polymers can be classified? Polymers can be classified as natural polymers or synthetic polymers.

3、 9.3 PolymersMany important types of biological molecules are natural polymers. Organisms produce these polymers in their cells. Synthetic polymers are developed by chemists in research laboratories and manufactured in factories. Both types of polymers have industrial uses. Silk and cotton fabrics a

4、re woven from natural polymer fibers, while polar fleece is made from a synthetic polymer. 9.3 PolymersWhat are three examples of synthetic polymers? Synthetic PolymersRubber, nylon, and polyethylene are three examples of compounds that can be synthesized. 9.3 PolymersRubber The sap collected from r

5、ubber trees in tropical regions contains rubber. Chemists produced a synthetic rubber, using hydrocarbons from petroleum. Natural rubber and synthetic rubbers contain different monomers and have different properties. Synthetic Polymers 9.3 PolymersNylon Research to make artificial silk led to nylon,

6、 which has properties not found in natural polymers. Nylon fibers are very strong, durable, and shiny. Nylon is used in parachutes, windbreakers, fishing line, carpets, and ropes. Synthetic Polymers 9.3 PolymersPolyethylenePolyethylene forms when ethene (or ethylene) molecules link head to tail. The

7、 number of carbon atoms in a polyethylene chain affects the properties of the polymer. The more carbon atoms in the chain, the harder the polymer is.Synthetic Polymers 9.3 PolymersA Rubber is used to manufacture tires. B Nylon fibers are strong and do not wear out easily. C Hard plastic shapes can b

8、e made from a polyethylene polymer. Synthetic Polymers 9.3 PolymersWhat are four types of polymers that organisms can produce? Natural PolymersFour types of polymers produced in plant and animal cells are starches, cellulose, nucleic acids, and proteins. 9.3 PolymersStarchesSimple sugars have the fo

9、rmula C6H12O6. They can exist as straight chains or rings. Fructose and glucose can react to form sucrose (table sugar).Glucose monomers join to form starches as shown below.Natural Polymers 9.3 PolymersSimple sugars, slightly more complex sugars such as sucrose, and polymers built from sugar monome

10、rs are all classified as carbohydrates.Typically, a starch contains hundreds of glucose monomers. Plants store starches for food and to build stems, seeds, and roots. Natural Polymers 9.3 PolymersAll the foods shown contain starch, which is a polymer of the simple sugar glucose. Natural Polymers 9.3

11、 PolymersCellulose The carbohydrate cellulose is the main component of cotton and wood. Cellulose molecules contain 3000 or more glucose monomers. Cellulose gives strength to plant stems and tree trunks. Natural Polymers 9.3 PolymersNucleic AcidsNucleic acids are large nitrogen-containing polymers f

12、ound mainly in the nuclei of cells. There are two types of nucleic acid, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).Nucleic acids in each cell of a plant or animal store information about its structures and functions. Natural Polymers 9.3 PolymersThe monomers in a nucleic acid are nucleo

13、tides. A DNA nucleotide has three parts: a phosphate group, deoxyribose sugar, and an organic base. When two strands of DNA line up, pairs of bases are arranged like the rungs of a ladder. Natural Polymers 9.3 PolymersThe strands in DNA are held together by strong intermolecular attractions between

14、hydrogen atoms on one strand and nitrogen or oxygen atoms on the other strand. The strands twist around each other in a structure called a double helix. The order of the base pairs in a strand is a code that stores information that is used to produce proteins.Natural Polymers 9.3 PolymersNatural Pol

15、ymers 9.3 PolymersProteinsOrganic acids contain a COOH group, and organic bases contains an NH2 group. An amino acid is a compound that contains both carboxyl and amino functional groups in the same molecule. Natural Polymers 9.3 PolymersThere are about 20 amino acids that your body needs to functio

16、n. They include glycine and phenylalanine. Natural Polymers 9.3 PolymersYour cells use amino acids as the monomers for constructing protein polymers. A protein is a polymer in which at least 100 amino acid monomers are linked through bonds between an amino group and a carboxyl group. The instruction

17、s for making proteins are stored in DNA. Your body may contain as many as 300,000 different proteins.Natural Polymers 9.3 PolymersThese foods are all good protein sources.Natural Polymers 9.3 PolymersAssessment Questions1. A synthetic polymer that can be formed into strong fibers suitable for making

18、 cloth and rope is a. silk.b. high-density polyethylene.c. natural rubber.d. nylon. 9.3 PolymersAssessment Questions1. A synthetic polymer that can be formed into strong fibers suitable for making cloth and rope is a. silk.b. high-density polyethylene.c. natural rubber.d. nylon.ANS: D 9.3 PolymersAs

19、sessment Questions2. The strong natural fiber, cellulose, is a polymer made of long chains of what type of molecule? a. amino acidb. organic basesc. hydrocarbonsd. sugar 9.3 PolymersAssessment Questions2. The strong natural fiber, cellulose, is a polymer made of long chains of what type of molecule?

20、 a. amino acidb. organic basesc. hydrocarbonsd. sugarANS: D 9.3 PolymersAssessment Questions1. A large molecule that forms when many smaller molecules are linked together by covalent bonds is a monomer. TrueFalse 9.3 PolymersAssessment Questions1. A large molecule that forms when many smaller molecules are linked together by covalent bonds is a monomer. TrueFalseANS: F, polymer