Name: polymer chains and their properties
Uploaded: 2023-04-30T18:28:47.000Z
Duration: 2 min 34 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.18

SC.912.L.18.1

Polymers

Un polymère est une chaîne de petites molécules, appelés monomères, qui sont maintenus ensemble par des liaisons covalentes. Les organismes peuvent synthétiser des polymères biologiques, ou les scientifiques peuvent synthétiser des polymères en laboratoire. Les polymères naturels comprennent l'ADN, le matériel génétique trouvé dans tous les organismes vivants, et protéines, polysaccharides, et les lipides, les éléments constitutifs de la vie.Les plastiques font partie des polymères synthétiques les plus courants et comprennent le nylon, le polyéthylène et le téflon. Le processus de liaison des monomères les uns aux autres pour former une molécule plus grosse est connue sous le nom de polymérisation. Les monomères polymérisent par deux mécanismes de réaction distincts, condensation et addition.La polymérisation par condensation est quand deux monomères avec un atome d'hydrogène réactif et groupe hydroxyle, respectivement, liés les uns aux autres avec la libération d'eau comme sous-produit. La plupart des polymères naturels sont formés par des réactions de condensation. En plus de la polymérisation, des monomères avec des doubles liaisons carbone-carbone s'ajoutent les unes aux autres pour former un polymère sans génération de sous-produit par la libération d'atomes.Polymères constitués du même type de monomères sont connus sous le nom d'homopolymères, et ceux constitués de différents types de monomères sont appelés hétéropolymères. La cellulose, le polymère naturel le plus abondant, est un homopolymère du glucose, tandis que l'agarose, un polymère d'origine marine, est un hétéropolymère de galactose et 3, 6-anhydro-L-galactopyranose. Les polymères ont différentes structures en fonction sur leur type de monomères.Les polymères linéaires sont de longues chaînes de monomères. Par exemple, la cellulose est un polymère linéaire maintenu ensemble par des liaisons bêta 1, 4-glycosidiques. Les polymères ramifiés ont des chaînes qui se séparent d'une chaîne principal, telle que l'amylopectine, un composant de l'amidon qui se ramifie après 24 à 30 monomères par le biais de liaisons alpha glycosidiquesiaisons 1, 6.Les polymères réticulés ont deux chaînes ou plus maintenues ensemble en plusieurs points comme une échelle, comme un polymère construit d'échelle de silicium, ou forment un réseau complexe de chaînes interconnectées comme le gel formé par les pectines dans les gelées et les marmelades.

polymères

Le mot polymère est dérivé des mots grecs “poly” qui signifie “beaucoup” et “mer” qui signifie “pièces” Les polymères sont de longues chaînes de molécules composées d'unités répétitives de molécules plus petites, appelées monomères. Ils se produisent naturellement, comme l'ADN et les protéines, ou peuvent être construits synthétiquement, comme les plastiques. Ils ont des caractéristiques structurelles variées, telles que des chaînes linéaires, chaînes ramifiées, ou réseaux complexes, qui contribuent aux propriétés qu'ils présentent. De plus, les groupes fonctionnels qui peuvent être présents sur un polymère définissent davantage leurs propriétés. Les unités individuelles d'un polymère sont maintenues ensemble par des liaisons covalentes stables qui se produisent soit par l'addition ou polymérisation par condensation. Polymérisation par addition Une polymérisation supplémentaire se produit lorsque les monomères qui participent à la réaction ont des doubles liaisons. Cette réaction nécessite la présence d'une molécule externe qui a un électron de valence non apparié pour initier la réaction. Cet électron non apparié est hautement réactif et forme une liaison avec l'une des doubles liaisons d'un monomère, ce qui conduit le monomère à avoir un électron de valence non apparié. Cet électron de valence non apparié s'associe ensuite à un autre monomère avec des doubles liaisons conduisant à une réaction en chaîne où la molécule continue d'ajouter d'autres monomères avec des doubles liaisons. Cela entraîne la formation d'une chaîne de monomères, celui ajouté le plus récemment ayant un électron de valence non apparié. Cette réaction d'addition se poursuit jusqu'à ce que deux chaînes avec des électrons non appariés réagissent entre elles pour former une liaison. Cela élimine tous les électrons de valence non appariés, ce qui entraîne la fin de la réaction. Polymérisation par condensation La polymérisation par condensation, également connue sous le nom de polymérisation en croissance par étapes, nécessite un catalyseur, tel qu'un acide ou une enzyme, et les monomères doivent avoir au moins deux groupes fonctionnels réactifs, tels que des amines ou des acides carboxyliques. Les groupes fonctionnels sur les monomères réagissent les uns avec les autres pour former des liaisons telles que des liaisons ester ou amide et s'accompagnent de la perte d'une petite molécule, telle que l'eau. La polymérisation par condensation est une réaction plus lente que la polymérisation par addition et, dans de nombreux cas, nécessite la présence de chaleur. Ce texte est adapté de <a href=""https://openstax.org/books/chemistry-2e/pages/Hydrocarbons"">Openstax, Chemistry 2e, Chapitre 20.1 : Hydrocarbures</a>.

Polymères

Le mot polymère est dérivé des mots grecs « poly » qui signifie « beaucoup » et « mer » qui signifie « parties ». ...

Education

Enseignement

JoVE Core

Cell Biology

Biologie cellulaire

Unit 1

Unité 1

Biochemistry of the Cell

Biochimie de la cellule

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

polymer chains and their properties

Polymers are large molecules made from repeating units called monomers. These long chains can form many common materials. Their structure helps explain why different polymers can behave in different ways.

Polymers can be built in more than one way. Some form by addition polymerization, where monomers join together directly. Others form by condensation polymerization, which releases a small molecule as the chain grows.

The type of polymer affects its properties and uses. Some polymers are strong and flexible, while others are more rigid. Many everyday materials are made from polymers, so understanding how they form helps explain the materials people use every day.

Polymer Chains and Their Properties

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Elements in the Human Body and Periodic Table

Elements are the smallest units of matter that cannot be broken down further by chemical processes. Scientists know 118 elements, but not all of them occur naturally. Only a small number are essential for life, and living matter depends mostly on carbon, nitrogen, hydrogen, and oxygen. The periodic table organizes elements by their physical and chemical properties. Each square shows the element name, chemical symbol, atomic number, and atomic weight. The atomic number is the number of protons...

functional groups

Functional Groups in Organic Molecules

Functional groups are the part of an organic molecule that gives it specific chemical behavior. They help explain why compounds with similar carbon skeletons can react in different ways. In organic chemistry, these groups are often used to classify compounds. A functional group can change the properties of a molecule and affect how it behaves in a reaction. Knowing functional groups helps students recognize patterns in organic compounds. It also makes it easier to compare molecules that share...

types of chemical bonds

Chemical Bonds and How Atoms Join

Chemical bonds hold atoms together and help explain how different substances form. In chemistry, the main bond types are ionic bonds, covalent bonds, and metallic bonds. Ionic bonds form when electrons move from one atom to another. Covalent bonds form when atoms share electrons. Metallic bonds occur in metals, where electrons are held in a shared arrangement that gives metals their characteristic behavior. Understanding these bond types helps students compare how atoms connect in different...

noncovalent attractions in biomolecules

Biomolecule Interactions Without Covalent Bonds

Biomolecules often stay together through noncovalent attractions instead of covalent bonds. These weaker interactions help molecules recognize each other and form structures needed for life. The main noncovalent attractions are hydrogen bonds, electrostatic interactions, van der Waals forces, and hydrophobic interactions. Each one works in a different way, but all of them can influence how biomolecules fold, bind, and behave in cells. Hydrogen bonds form when a hydrogen atom is attracted to...

polymers

Polymers are large molecules made from repeating units called monomers. These long chains can form many common materials. Their structure helps explain why different polymers can behave in different ways. Polymers can be built in more than one way. Some form by addition polymerization, where monomers join together directly. Others form by condensation polymerization, which releases a small molecule as the chain grows. The type of polymer affects its properties and uses. Some polymers are...

what are lipids?

Lipids in Cells: Membranes, Energy, and Signals

Lipids are important cell molecules that act as membrane parts, energy stores, and signaling molecules. They are a diverse group of hydrocarbons, which are compounds made of carbon and hydrogen atoms. The carbon-carbon and carbon-hydrogen bonds are nonpolar, so lipids have an overall nonpolar character. Lipids are also hydrophobic, or “water-hating.” They do not form hydrogen bonds with water, so they are nearly insoluble in water. They are, however, soluble in organic solvents such as...

structure of lipids

How Lipid Molecules Are Built

Lipid molecules are built from hydrocarbon chains and a few key structural parts. Their shape helps explain why they behave differently from many other biological molecules. In high school biology, this structure is often linked to how lipids store energy and help form cell membranes. Some lipids are made from fatty acids joined to other small molecules. Triglycerides contain glycerol and three fatty acids, while phospholipids contain glycerol, two fatty acids, and a phosphate group. These...

chemistry of carbohydrates

Carbohydrate Structure and Bonding

Carbohydrates are built from sugar units and the bonds that link them. Their chemistry explains how simple sugars join to form larger molecules. It also helps show why carbohydrates have different structures and functions. The video focuses on the main sugar types found in carbohydrates. These include monosaccharides, disaccharides, and polysaccharides. Monosaccharides are single sugar units. Disaccharides contain two sugar units, while polysaccharides are long chains of many sugar units. The...

nucleic acids

DNA and RNA in Cells

DNA and RNA are nucleic acids that help store and use genetic information in cells. They are key molecules in biology and are often studied together because they work as a pair in living systems. Nucleic acids are built from repeating units called nucleotides. Each nucleotide has a sugar, a phosphate group, and a nitrogenous base. The order of these bases carries the genetic code. There are two main nucleic acids: DNA, or deoxyribonucleic acid, and RNA, or ribonucleic acid. DNA usually stores...

protein and protein structures

How Protein Shape Determines Function

Proteins are essential molecules in living things, and their shape affects how they work. Protein structure is described at several levels, including primary, secondary, tertiary, and quaternary structure. These levels help explain how a protein is built and how its final form supports its job. Primary structure is the sequence of amino acids in a protein. Secondary structure forms when parts of the chain fold into regular patterns. Tertiary structure is the overall three-dimensional shape of...

ph regulation in cells

Cell pH and Organelle Balance

Cell pH and organelle balance are essential for normal cell function. pH affects protein shape and activity, the charge on cell membranes, and many metabolic reactions inside the cell. Cells also use the proton motive force, which is the energy stored in a proton gradient, to make ATP, the cell’s main energy molecule. The cytosol, or fluid inside the cell, is usually slightly more acidic than the fluid outside the cell. Even so, cells must stop the cytosol from becoming too acidic. They use...

chemistry of the cell

Cell Chemistry: Water, Ions, and Molecules

Cell chemistry explains the substances that make cells work. Water is the main component of cells, and it supports the chemical reactions that keep life going. Cells also contain organic molecules, which are carbon-based compounds, and inorganic ions, which are charged particles needed for cell function. Organic molecules in cells include carbohydrates, lipids, proteins, and nucleic acids. These molecules have different roles, but together they build cell structures, store energy, and carry...

key terms and concepts

Learn how polymers are built from repeating monomers and how addition and condensation polymerization shape the properties of everyday materials.

Polymer Chains and Their Properties | JoVE K12

cell biology

JoVE Core Biologie cellulaire illustre les processus cellulaires complexes dans des leçons vidéos complètes mais faciles à comprendre. Cette collection se concentre sur les composants et fonctions essentiels de la cellule ; cela inclut les organelles et les membranes ainsi que le transport et le métabolisme énergétique cellulaire. Elle est complétée par nos vidéos de scientifiques à l'action qui démontrent l'application de la biologie cellulaire dans des expériences concrètes.

Macromolecules

Biomolecules
Organisms contain a wide variety of organic molecules with numerous functions which depend on the chemical structures and properties of these ...

What are Lipids?

Lipids function as structural components of cellular membranes, in addition to acting as energy reservoirs and signaling molecules. They are thus crucial ...

Structure of Lipids

lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

Fats and lipids are crucial components in the human body. Some lipid-derived compounds, such as fat-soluble vitamins, eicosanoids, lipoproteins, and ...

Fats as Energy Storage Molecules

Amino acids

Amino acids are the monomers that comprise proteins. Each amino acid has the same fundamental structure, which consists of a central carbon atom, or the ...

Peptide Bonds

A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid&#39;s carboxyl group and another amino acid&#39;s amino ...

What are Proteins?

Protein and Protein Structures

Protein Organization

Globular Proteins

In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins ...

Fibrous Proteins

Fibrous proteins are either long and narrow proteins or assemble to form long and thin structures. They contain repetitive units and usually consist of ...

Protein Denaturation

The function of proteins depends on their native three-dimensional structure, which is dictated by the amino acid sequence of the specific protein. ...

Role of Proteins in the Human Body

Proteins are the building block of life. They are also&#160; the most abundant macromolecules with as many diverse roles in the body. They are part of ...

Mechanical Protein Function

Structural Protein Function

Introduction to Carbohydrates

Carbohydrates, proteins, and fats are the primary macronutrients in the human diet. However, carbohydrates are the most favored source of energy in the ...

Chemistry of Carbohydrates

Sugars as Energy Storage Molecules

Nucleic Acids and Nucleotides

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and have instructions for its ...

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group ...

The DNA Helix

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Noncovalent Attractions in Biomolecules

Describe the basic molecular structures and primary functions of the four major categories of biological macromolecules.

Cellulose and Pectic Polysaccharides

&#160;Every plant cell has a cell wall that protects the cell, provides structural support, and gives the cell shape. Cellulose, the main structural ...

Membrane Carbohydrates

The plasma membrane is a dynamic barrier composed of lipids, proteins, and carbohydrates. It is the epicenter of many cellular processes required for cell ...

Describe the important structural characteristics of monosaccharides, disaccharides, and polysaccharides and explain the functions of carbohydrates in living things.

SC.912.L.18.2

Overview of Fatty Acid Metabolism

Lipids also are sources of energy that power cellular processes. Like carbohydrates, lipids are composed of carbon, hydrogen, and oxygen, but these atoms ...

What are Membranes?

A cell&#39;s plasma membrane demarcates the cell&#39;s borders and determines the nature of its interaction with the environment. Cells exclude certain ...

Membrane Fluidity

Membrane fluidity is explained by the fluid mosaic model of the cell membrane, which describes the plasma membrane structure as a mosaic of ...

Fluid Mosaic Model

Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane ...

Membrane Lipids

Lipids are an essential component of all biological membranes. The average lipid content in mammalian membranes is 50%, though it can be as low as 20% in ...

Asymmetric Lipid Bilayer

Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. ...

Lipids as Anchors

In the plasma membrane, the lipids forming the bilayer can also act as an anchor to tether proteins to the membrane. The three main types of lipid anchors ...

The Significance of Membrane Transport

The transport of solutes across the cell membrane is essential for metabolic processes, like maintaining cell size and volume, generating the action ...

Describe the structures of fatty acids, triglycerides, phospholipids, and steroids. Explain the functions of lipids in living organisms. Identify some reactions that fatty acids undergo. Relate the structure and function of cell membranes.

SC.912.L.18.3

Ligand Binding Sites

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic ...

Introduction to Enzymes

The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an ...

Enzymes and Activation Energy

The activation energy (or free energy of activation), abbreviated as Ea, is the small amount of energy input necessary for all chemical reactions to ...

Introduction to Enzyme Kinetics

Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate ...

Turnover Number and Catalytic Efficiency

The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from ...

Catalytically Perfect Enzymes

The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at ...

introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

For many years, scientists thought that enzyme-substrate binding took place in a simple &#34;lock-and-key&#34; fashion. This model stated that the enzyme ...

Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

Enzyme Activity

Biological Catalysts

All living organisms continuously perform numerous biochemical reactions to sustain their presence. Most of these reactions require ...

Describe the structures of proteins and amino acids. Explain the functions of proteins in living organisms. Identify some reactions that amino acids undergo. Relate the structure and function of enzymes.

SC.912.L.18.4

Chemiosmosis

Oxidative phosphorylation is a highly efficient process that generates large amounts of adenosine triphosphate (ATP), the basic unit of energy that drives ...

electron-transport-chain-complex-i-and-ii

Electron Transport Chain: Complex I and II

The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce ...

electron-transport-chain-complex-iii-and-iv

Electron Transport Chain: Complex III and IV

During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then ...

The Electron Transport Chain

The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is ...

the-supercomplexes-in-the-crista-membrane

The Supercomplexes in the Crista Membrane

The mitochondrial cristae membrane is the primary site for the oxidative phosphorylation (OXPHOS) process of energy conversion mediated through ...

ATP Synthase: Structure

ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in ...

ATP Synthase: Mechanism

In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear ...

The ADP/ATP Carrier Protein

ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, ...

ATP Yield

Cellular respiration produces 30 - 32 ATP per glucose molecule. Although most of the ATP results from oxidative phosphorylation and the electron transport ...

Discuss the use of chemiosmotic gradients for ATP production in chloroplasts and mitochondria.

SC.912.L.18.5

Fermentation

Most eukaryotic organisms require oxygen to survive and function adequately. Such organisms produce large amounts of energy during aerobic respiration by ...

biofuels-producing-ethanol-from-cellulosic-material

Biofuels: Producing Ethanol from Cellulosic Material

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
In this experiment, cellulosic material (such as corn stalks, leaves, ...

Discuss the role of anaerobic respiration in living things and in human society.

SC.912.L.18.6

Photosynthesis

Autotrophs

Almost all living organisms on Earth depend on photosynthesis, which is the process that converts sunlight energy into a simple sugar called ...

What is Photosynthesis?

All living organisms on Earth are directly or indirectly dependent on photosynthesis. It is the only biological process that can capture energy from ...

The Anatomy of Chloroplasts

Green algae and plants, including green stems and unripe fruit, harbor specialized organelles called chloroplasts to carry out photosynthesis. They ...

Photosystems

Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in ...

The Photochemical Reaction Center

Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center ...

The Antenna Complex

Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - ...

the-z-scheme-of-electron-transport-in-photosynthesis

The Z-Scheme of Electron Transport in Photosynthesis

The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of ...

Identify the reactants, products, and basic functions of photosynthesis.

SC.912.L.18.7

A. All living things are composed of four basic categories of macromolecules and share the same basic needs for life.

B. Living organisms acquire the energy they need for life processes through various metabolic pathways (primarily photosynthesis and cellular respiration).

C. Chemical reactions in living things follow basic rules of chemistry and are usually regulated by enzymes.

D. The unique chemical properties of carbon and water make life on Earth possible.

Polymer Chains and Their Properties

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