The Building Blocks of Life

Organic CompoundsAre carbon containing compoundsCarbon has the ability to form covalent bonds that are strong and stable

CarbohydratesCommonly known as sugars and starchesCHO-means that the compound contains carbon, hydrogen, and oxygen in a ratio of 1:2:1; is also the abbreviation for carbohydratesThe primary function of carbohydrates is to store and release energyThere are three categories of CHO, mono, di, and polysaccharides

Monosaccharides *are the simplest carbohydrates; contain one

sugarEx. Glucose-sugar green plants produce and most living organisms use as

their energy sourceEx. Galactose; found in milkEx. Fructose; found in fruits

Chemical formula for each monosaccharide is C6H12O6

The arrangement of the atoms makes each compound different. Therefore, they are isomers of each other.

Structural Formulas of Simple Sugars

Disaccharides

*Composed of two simple sugars or monosaccharides

– Ex. Sucrose (glucose + fructose); table sugar

– Ex. Maltose (glucose + glucose); malt sugar

– Ex. Lactose (glucose + galactose); milk sugar

– Molecular formula C12H22O11can derive the formula by dehydration synthesis

PolysaccharidesAre the largest carbohydrate moleculeComposed of at least three monosaccharidesIs the form in which living things store excess sugarEx. Starch, cellulose, and glycogen– Molecular formula is (C6H10O5)n– n=the # of repeating units

Starch consists of highly branched chains of glucose units and is used as food storage by plants; potatoes and grains

Cellulose another glucose polymer that forms the cell walls of plants and gives structural support (strength and rigidity); made of glucose units hooked together like a chain-link fence; found in plants and is a major component of wood

Glycogen-animals store food in this form; is another polymer, but is more highly branched than starch; found in the liver and muscles of animals

The Structure of LipidsAre organic compounds with a large proportion of C-H bonds and less O2 than CHOCommonly called fats, oils, and waxes; fats and waxes are usually solids at room temp., oils are liquids; waxes consist of one fatty acid linked to an alcoholAre insoluble in water because their molecules are non-polar (not attracted by H2O)

Most common type consists of 3 fatty acids bonded to a molecule of glycerol; triglyceride

Lipids have various functions– Can be used to store energy– Used to form biological membranes– Act as chemical messengers (use it as a

starting material for making other steroids, including male and female sex hormones)

– Steroids are lipids; cholesterol is an example– Too much cholesterol may lead to

artherosclerosis

Types of Lipids or FatsSaturated fats occur when every carbon (C) atom in a fatty acid chain is joined to another C by a single bond; found in meats, most dairy productsUnsaturated fats occur when a pair of C atoms is joined by one double bondPolyunsaturated fats occur when a fatty acid contains at least two double bonds; tend to be liquids at room temp; Ex. Cooking oils such as olive, corn, canola, and peanut oils

Sterols (Steroids) play a number of important roles in building cells and carrying messages from one part of the body to another: Ex. Cholesterolused for vitamin D synthesisUsed for bile saltsMembrane structureSteroid hormone synthesisPhospholipids are molecules that consist of parts that dissolve well in water and parts that do not; play key roles in forming cell membranes from their ability to form bilayers

ProteinsAre essential to all lifeAre composed of nitrogen in addition to CHOAre polymers of amino acids (aa) (building blocks of proteins); long chains of aa produces a proteinHas an amino group on one end and a carboxyl group on the other end

Protein Structure

Four Levels of Protein Structure

Descriptions of 4 Protein LevelsPrimary (1st)-linear sequence of amino acidsSecondary (2nd)-part of the polypeptide coils or folds into alpha helices and pleated sheets; twisted or foldedTertiary (3rd)-overall 3D shape of the polypeptide; fibrous or globularQuaternary (4th)-consists of 2 or more polypeptide chains or subunitsVan der Waals forces and hydrogen bonds help maintain a protein’s shape

Seven Classes of ProteinsStructural-silk of spiders and hair fibersContractile-muscle movementStorage-ovalbumin (egg white); source of amino acids for developing embryosDefensive-antibodies fight infectionTransport-hemoglobin transports oxygen in the bloodstreamSignal-hormones help coordinate body activities (sending messages)Enzymes-serve as chemical catalysts to speed up reactions

Nucleic AcidsLarge, organic molecules (macromolecules) composed of CHONP atomsStores information in cells in the form of a codeAre polymers of individual monomers known as nucleotidesNucleotides are composed of a 5C sugar, a nitrogenous base, and a phosphate (PO4 group)Are two types; DNA and RNADNA is the master copy of an organism’s information code; it forms the genetic codeRNA forms a copy of DNA for use in protein synthesis

DNA vs RNA

DNA consists of a double helical structure; it contains the sugar deoxyribose, and the bases adenine, thymine, cytosine, guanine

RNA consists of a single strand; it contains the sugar ribose, and the bases adenine, uracil, cytosine, and guanine

Enzymes

EnzymesAre proteinsSpeed up a reaction by binding to the reactants (substrates).Substrates bind to enzymes at a region known as the active site.Are very specific; a particular enzyme can catalyze only one particular chemical reaction involving specific substrates.

EnzymesAre important in regulating chemical pathways, synthesizing materials, needed by cells, releasing energy and transferring information.Are involved in digestion, respiration, reproduction, vision, movement, thought, and in the making of other enzymes.

EnzymesAre catalysts that work by lowering the ”start-up” energy of a reaction.Every enzyme has conditions for which it is most effective.Temperature affects molecular motion.Optimal temperature produces the highest rate of contact between reactant molecules and the enzyme's active site.

EnzymesHigher temperature denatures the enzymes, altering it’s specific 3-D shape and destroying it’s function.Salt concentration and pH also influence enzyme activity.Optimal pH is between 6-8.Outside this range, enzyme action and normal chemical functioning of cells maybe impaired.

The Effect of an Enzyme on EA

Enzyme Substrate Complex

Competitive Inhibition

Noncompetitive Inhibitors

Properties of WATER

Properties of WaterServes as a means of transport of materials in organisms; ex. Plant sap and blood are mostly waterIs a polar molecule (a molecule that has an unequal distribution of charges); it also easily attracts other H2O moleculesMakes up about 70-95% of most organismsComposed of 2 atoms of H+ linked by covalent bonds to 1 atom of O2

Structural Formulas of Water

Water is the most abundant compound in nearly all living organisms

Water is slightly charged on each end; makes it good at forming mixtures (solutions and suspensions)

Solutions-the molecules are uniformly spread throughout the water

Solvent does the dissolving; solute is the substance that is dissolvedWater is the universal solvent

Suspensions are mixtures of water and nondissolved materials

The Uniqueness of WaterHas a high surface tension; ex. H2O skier, water striderCohesion-attraction between molecules of the same substanceAdhesion-attraction between molecules of different substancesWater creeps up in thin tubes; capillary action Ex. Plants get H2O from the groundHas a high heat of vaporization; Ex. Helps cool the body when sweatingResists temperature change; water must lose a lot of heat when it cools; requires more heat to increase the temperature than do most other common substances

Water expands when it freezes; Ex. If H2O freezes inside the cracks of rocks, it often breaks apart the rocks forming soil over a long period of time.

Acids, Bases, and pHpH scale-indicates the concentration of H+ ions in solutionsAcids-any compound that forms H+ ions in solution; acidic solutions contain a higher concentration of these ions than pure water and have pH values below 7Bases-a compound that produces OH- ions in solution; basic or alkaline solutions contain lower concentrations of H+ ions that pure water and has pH values above 7Buffers-dissolved compounds; weak acids or bases that can react with strong acids or bases to prevent sharp, sudden change in pH