Proteins, Carbohydrates, And Lipids
3Proteins, Carbohydrates,and LipidsPatrick Charnay : charnay@biologie.ens.frMorgane Thomas-Chollier : mthomas@biologie.ens.frSite web compagnon livre Savada Life 9ème édition p#t 542578
1.4 Proteins
1.4 Proteins Biological molecules are polymers,constructed from the covalent binding ofsmaller molecules called monomers Proteins polymers are linear combinationof amino acids monomers
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Carbohydrates have the general formulaCn(H2O)n3 main roles: Source of stored energy Transport stored energy Carbon skeletons that can be rearrangedto form new molecules
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Monosaccharides: simple sugars monomerDisaccharides: two simple sugars linked bycovalent bondsOligosaccharides: three to 20monosaccharidesPolysaccharides: hundreds or thousands ofmonosaccharides—starch, glycogen,cellulose
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?All cells use glucose (monosaccharide)as an energy source.“fuel” of the living worldFound for example in honey, fruits
Figure 3.13 From One Form of Glucose to the Other
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?All cells use glucose (monosaccharide)as an energy source.Exists as a straight chain or ring form.Ring is more common—it is morestable.Ring form exists as α- or β-glucose,which can interconvert.
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Monosaccharides have different numbersof carbons:Hexoses: six carbons—structuralisomersPentoses: five carbons
Figure 3.14 Monosaccharides Are Simple Sugars
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Monosaccharides bind together incondensation reactions to formglycosidic linkages.Glycosidic linkages can be α or β.
Figure 3.15 Disaccharides Form by Glycosidic Linkages (Part 1)
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Often covalently bonded to proteins andlipids on cell surfaces and act asrecognition signals.Human blood groups get specificity fromoligosaccharide chains.http://www.ftlpo.net
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Polysaccharides are giant polymers ofmonosaccharides.Polysaccharides of glucose:Starch (amidon): storage of glucose inplantsGlycogen: storage of glucose in animalsCellulose: very stable, good for structuralcomponents
Figure 3.16 Representative Polysaccharides (Part /tech stof cellulose 01.gif
Figure 3.16 Representative Polysaccharides (Part 1)
Figure 3.16 Representative Polysaccharides (Part 2)
3.3 What Are the Chemical Structures and Functions ofCarbohydrates?Carbohydrates can be modified by theaddition of functional groups:Sugar phosphateAmino sugars (eg. Glucosamine)Chitin
3.4 summaryProteins formed by a linear combination ofamino acids monomers (among 20) bypeptide linkageCarbohydrates formed by linear orbranched combination of monosaccharidesmonomers by glycosidic linkage
3.4 What Are the Chemical Structures and Functions ofLipids?Lipids are nonpolar hydrocarbons.When sufficiently close together, weak butadditive van der Waals forces hold themtogether.Not polymers in the strict sense, becausethey are not covalently bonded. Aggregatesof individual lipids
3.4 What Are the Chemical Structures and Functions ofLipids? Fats and oils store energy Phospholipids—structural role in cell membranes Carotenoids and chlorophylls—capture light energy inplants (photoreceptor) Steroids and modified fatty acids—hormones andvitamins Animal fat—thermal insulation Lipid coating around nerves provides electricalinsulation Oil and wax on skin, fur, and feathers repels water
3.4 What Are the Chemical Structuresand Functions of Lipids?Fats and oils are triglycerides(simple lipids):composed of fatty acids and glycerolGlycerol: 3 —OH groups (an alcohol)Fatty acid: nonpolar hydrocarbon with a polarcarboxyl groupCarboxyls bond with hydroxyls of glycerol in anester linkage.
Figure 3.18 Synthesis of a Triglyceride
3.4 What Are the Chemical Structures and Functions ofLipids?Saturated fatty acids: no double bondsbetween carbons—it is saturated with Hatoms.Unsaturated fatty acids: some doublebonds in carbon chain.monounsaturated: one double bondpolyunsaturated: more than one
Figure 3.19 Saturated and Unsaturated Fatty Acids (Part 1)
Figure 3.19 Saturated and Unsaturated Fatty Acids (Part 2)
3.4 What Are the Chemical Structures and Functions ofLipids?Animal fats tend to be saturated: packedtogether tightly; solid at room temperature.Plant oils tend to be unsaturated: the“kinks” prevent packing; liquid at roomtemperature.
3.4 What Are the Chemical Structures and Functions ofLipids?Fatty acids are amphipathic: they haveopposing chemical properties.When the carboxyl group ionizes it formsCOO– and is strongly hydrophilic; theother end is e-et-tensioactif
3.4 What Are the Chemical Structuresand Functions of Lipids?Phospholipids: fatty acids bound toglycerol; a phosphate group replacesone fatty acid. Phosphate group is hydrophilic—the“head” “Tails” are fatty acid chains—hydrophobic They are amphipathic
Figure 3.20 Phospholipids (Part 1)
3.4 What Are the Chemical Structures and Functions ofLipids?In water, phospholipids line up with thehydrophobic “tails” together and thephosphate “heads” facing outward, toform a bilayer.Biological membranes have this kind ofphospholipid bilayer structure.
Figure 3.20 Phospholipids (Part 2)
Figure 3.21 β-Carotene is the Source of Vitamin ACarotenoids: light-absorbing pigments
Figure 3.22 All Steroids Have the Same Ring StructureSteroids: multiple rings share carbons
3.4 What Are the Chemical Structures and Functions ofLipids?Vitamins—small molecules notsynthesized by the body and must beacquired in the diet.Not all vitamins are lipids ! vitamin A, K, D, E
3.4 summaryProteins formed by a linear combination ofamino acids monomers (among 20) bypeptide linkageCarbohydrates formed by linear orbranched combination of monosaccharidesmonomers by glycosidic linkageLipids form large structures but theinteractions are not covalent. Non polar andamphiphatic molecules
3Nucleic Acids and the Originof Life
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?Nucleic acids are polymers specializedfor the storage, transmission, and use ofgenetic information.DNA deoxyribonucleic acidRNA ribonucleic acid
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?The monomeric units are nucleotides.Nucleotides consist of a pentose sugar, aphosphate group, and a nitrogencontaining base.
Figure 4.1 Nucleotides Have Three Components
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?RNA has riboseDNA has deoxyribose
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?The “backbone” of DNA and RNA is achain of sugars and phosphate groups,bonded by phosphodiester linkages.The phosphate groups link carbon 3′ inone sugar to carbon 5′ in another sugar.The two strands of DNA run in oppositedirections (antiparallel).
Figure 4.2 Distinguishing Characteristics of DNA and RNAPolymers (Part 1)
Figure 4.2 Distinguishing Characteristics of DNA and RNAPolymers (Part 2)
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?DNA bases: adenine (A), cytosine (C),guanine (G), and thymine (T)Complementary base pairing:A–TC–GPurines pair with pyrimidines byhydrogen bonding.Instead of thymine, RNA uses the baseuracil (U).
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?The two strands of a DNA molecule form adouble helix.All DNA molecules have the same structure;diversity lies in the sequence of base pairs.DNA is an informational molecule:information is encoded in the sequences ofbases.
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?The two functions of DNA comprise thecentral dogma of molecular biology: DNA can reproduce itself (replication). DNA can copy its information into RNA(transcription). RNA can specify asequence of amino acids in apolypeptide (translation).
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?The complete set of DNA in a livingorganism is called its genome.DNA carries hereditary informationbetween generations.Determining the sequence of bases helpsreveal evolutionary relationships.The closest living relative of humans isthe chimpanzee (share 98% DNAsequence).
4.1 What Are the Chemical Structures and Functions ofNucleic Acids?Other roles for nucleotides:ATP—energy transducer in biochemicalreactions
4.1 What Are the Chemical Structures and Functions of NucleicAcids?Unity of life through biochemical unityImplies a common origin of life
4.2 How and Where Did the Small Molecules of Life Originate?In the current conditions on Earth, livingorganisms arise from other livingorganismsEons ago,conditions on Earth and in theatmosphere were vastly different.About 4 billion years ago, chemicalconditions, including the presence ofwater, became just right for life.
4.2 How and Where Did the Small Molecules of Life Originate?Chemical evolution: conditions onprimitive Earth led to formation of simplemolecules (prebiotic synthesis); thesemolecules led to formation of life forms.Scientists have experimented withreconstructing those primitiveconditions.
4.2 How and Where Did the Small Molecules of Life Originate?Miller and Urey (1950s) set up anexperiment with gases thought to havebeen present in Earth’s earlyatmosphere.An electric spark simulated lightning as asource of energy to drive chemicalreactions.After several days, amino acids, purines,and pyrimidines were formed.
Figure 4.9 Miller & Urey Synthesized Prebiotic Molecules in anExperimental Atmosphere (Part 1)
Figure 4.9 Miller & Urey Synthesized Prebiotic Molecules in anExperimental Atmosphere (Part 2)
4.3 How Did the Large Molecules of Life Originate?Evidence that supports the “RNA World”hypothesis: Certain short RNA sequences catalyzeformation of RNA polymers. “Ribozyme” can catalyze assembly ofshort RNAs into a longer molecule. RNA as genetic material and able toperform metabolic processes
Figure 4.15 The Origin of Life
What about chemistry/engineering ? Bioplastics: derived from biopolymers such as cellulose andstarch Biofuels Companies dedicated to chemistry of renewable biomass toproduce chemicals for use in a wide variety of everydayproducts including plastics
What about chemistry/engineering ? DNA computers, DNA databases§ 2013: Scientists have recorded data includingShakespearean sonnets and an MP3 file on strands ofDNALETTERdoi:10.1038/nature11875Towards practical, high-capacity, low-maintenanceinformation storage in synthesized DNANick Goldman1, Paul Bertone1, Siyuan Chen2, Christophe Dessimoz1, Emily M. LeProust2, Botond Sipos1 & Ewan Birney1Digital production, transmission and storage have revolutionizedhow we access and use information but have also made archiving anincreasingly complex task that requires active, continuing maintenance of digital media. This challenge has focused some interest onDNA as an attractive target for information storage1 because of itscapacity for high-density information encoding, longevity undereasily achieved conditions2–4 and proven track record as an information bearer. Previous DNA-based information storage approacheshave encoded only trivial amounts of information5–7 or were notamenable to scaling-up8, and used no robust error-correction andlacked examination of their cost-efficiency for large-scale information archival9. Here we describe a scalable method that can reliablystore more information than has been handled before. We encodedcomputer files totalling 739 kilobytes of hard-disk storage and withan estimated Shannon information10 of 5.2 3 106 bits into a DNAcode, synthesized this DNA, sequenced it and reconstructed theoriginal files with 100% accuracy. Theoretical analysis indicates thatour DNA-based storage scheme could be scaled far beyond currentglobal information volumes and offers a realistic technology forlarge-scale, long-term and infrequently accessed digital archiving.In fact, current trends in technological advances are reducing DNAsynthesis costs at a pace that should make our scheme cost-effectivefor sub-50-year archiving within a decade.Although techniques for manipulating, storing and copying largeamounts of existing DNA have been established for many years11–13,digits (ASCII text), giving a total of 757,051 bytes or a Shannoninformation10 of 5.2 3 106 bits (see Supplementary Information andSupplementary Table 1 for full details).The bytes comprising each file were represented as single DNAsequences with no homopolymers (runs of 2 identical bases, whichare associated with higher error rates in existing high-throughputsequencing technologies19 and led to errors in a recent DNA-storageexperiment9). Each DNA sequence was split into overlapping segments, generating fourfold redundancy, and alternate segments wereconverted to their reverse complement (see Fig. 1 and SupplementaryInformation). These measures reduce the probability of systematicfailure for any particular string, which could lead to uncorrectableerrors and data loss. Each segment was then augmented with indexinginformation that permitted determination of the file from which itoriginated and its location within that file, and simple parity-checkerror-detection10. In all, the five files were represented by a total of153,335 strings of DNA, each comprising 117 nucleotides (nt). Theperfectly uniform fragment lengths and absence of homopolymersmake it obvious that the synthesized DNA does not have a natural(biological) origin, and so imply the presence of deliberate design andencoded information2.We synthesized oligonucleotides (oligos) corresponding to ourdesigned DNA strings using an updated version of Agilent Technologies’ OLS (oligo library synthesis) process20, creating ,1.2 3 107copies of each DNA string. Errors occur only rarely (,1 error per 500
What about maths ? Markov models used in DNA sequence analysis§ Gene prediction in DNA sequences Models for DNA evolution
What about physics/engineering? Biomaterials: matter, surface, or construct that interactswith biological systems§ Medecine: Artificial ligaments and tendons, Dentalimplants.
What about physics/engineering?Thermodynamics of molecular modelling computational techniques used to model or mimicthe behaviour of 4/Ion-Channel-Caught-Act.html
Innovation : engineering spider silk Protein fiber with exceptional mechanical properties, absorb a lot of energy before breaking able to stretch up to five times their relaxed length withoutbreaking artificially synthesize spider silk into fibers§ Genetically modified organisms (bacteria,silkworms,goat )to express spider proteins then purified 2013 : fibers produced by German company
tech_stof_cellulose_01.gif . Figure 3.16 Representative Polysaccharides (Part 1) Figure 3.16 Representative Polysaccharides (Part 2) 3.3 What Are the Chemical Structures and Functions of Carbohydrates? Carbohydrates can be modified by the addition of function
The large molecules important for all living things fall into four categories: carbohydrates, lipids, proteins, and nucleic acids. All of these, Proteins, Carbohydrates, Lipids and Nucleic Acids are very large molecules called macromolecules. In this lab, we will be conducting tests that reveal properties of carbohydrates, lipids, and proteins.
I can describe the structure of carbohydrates, lipids, proteins, and nucleic acids I can describe the function of carbohydrates, lipids, proteins, and nucleic acids I can identify monomers for macromolecules (carbohydrates, lipids, proteins, and nucleic acids) I can recognize common examples of macromolecules
carbohydrates, lipids, proteins, nucleic acids Monomers and Polymers - dehydration reactions Carbohydrates - Sugars and starches Lipids - Fats and oils - Phospholipids - How soap works Start proteins, if time 10 Sept. 2021 Carbohydrates Sugars Aldoses (Aldehyde Sugars) Ketoses (Ketone Sugars)
Carbohydrates 4 Proteins 4 Lipids 9 Nucleic Acids 0 TEST: Are you smart? If you eat a sandwhich with 46 grams of carbs and 24 grams of protein and 10 grams of fat, how much energy will you gain? Simple tests can detect the presence of proteins, lipids and carbohydrates in given samples
Lipids are one of the macronutrients. Lipids provide a concentrated source of energy. The term ‘lipid’ refers to both fats (solid at room temperature) and oils (liquid at room temperature). Elemental composition of lipids Lipids are made up of three elements: carbon (C), hydrogen (H) and oxygen (O). Chemical structure of lipids
animals few lipids can be used to synthesize carbohydrates or amino acids. Lipids include the vitamins A, D, E, and K, and include some non-vitamin enzyme cofactors. Lipids include a number of hormones, of which the most important are steroids and prostaglandins. Lipids act as insulation, and play a role in physical appearance of animals.
carbohydrates and lipids are integrated into the structure of biological membranes that surround the cell and intracellu-lar compartments. s0010 p0110 CARBOHYDRATES Nomenclature and structure of simple sugars The classic definition of a carbohydrate is a polyhydroxy aldehyde or ketone. The simplest carbohydrates, having two
Complex Carbohydrates Include starches and some forms of fiber. About 50% of your diet should come from complex carbohydrates. Examples of foods containing complex carbohydrates include pasta, wheat, corn, vegetables, fruit, sweet potatoes, beans and grains. Simple carbohydrates Include sugars such as glucose, fructose and sucrose.
