BIOCHEMISTRY

CARBOHYDRATES Living things use carbohydrates as a key source of ENERGY!Living things use carbohydrates as a key source of ENERGY! Plants use carbohydrates for structure (CELLULOSE)Plants use carbohydrates for structure (CELLULOSE) –include sugars and complex carbohydrates (starches) –contain the elements carbon, hydrogen, and oxygen (the hydrogen is in a 2:1 ratio to oxygen)

Monosaccharides (simple sugars) all have the formulaall have the formula C 6 H 12 O 6 all have a single ring structureall have a single ring structure –(glucose is an example)

Disaccharides (double sugars) all have the formulaall have the formula C 12 H 22 O 11 sucrose (table sugar) is an examplesucrose (table sugar) is an example

Polysaccharides Formed of three or more simple sugar unitsFormed of three or more simple sugar units Glycogen - animal starch stored in liver & musclesGlycogen - animal starch stored in liver & muscles Cellulose - indigestible in humans - forms cell wallsCellulose - indigestible in humans - forms cell walls Starches - used as energy storageStarches - used as energy storage

How are complex carbohydrates formed and broken down?

Dehydration Synthesis Combining simple molecules to form a more complex one with the removal of waterCombining simple molecules to form a more complex one with the removal of water –ex. monosaccharide + monosaccharide ----> disaccharide + water –(C6H12O6 + C6H12O6 ----> C12H22O11 + H2O Polysaccharides are formed from repeated dehydration syntheses of waterPolysaccharides are formed from repeated dehydration syntheses of water –They are the stored extra sugars known as starch

Hydrolysis Addition of WATER to a compound to SPLIT it into smaller subunitsAddition of WATER to a compound to SPLIT it into smaller subunits –(also called chemical digestion) –ex. disaccharide + H2O ---> monosaccharide + monosaccharide C12 H22 O11 + H2 O ---> C6 H12 O6 + C6 H12 O6

Lipids (Fats) Fats, oils, waxes, steroidsFats, oils, waxes, steroids Chiefly function in energy storage, protection, and insulationChiefly function in energy storage, protection, and insulation Contain carbon, hydrogen, and oxygen but the H:O is not in a 2:1 ratioContain carbon, hydrogen, and oxygen but the H:O is not in a 2:1 ratio Tend to be large molecules -- an example of a neutral lipid is belowTend to be large molecules -- an example of a neutral lipid is below

3 fatty acids + glycerol ----> fat (lipid)3 fatty acids + glycerol ----> fat (lipid) Fats -- found chiefly in animalsFats -- found chiefly in animals Oils and waxes -- found chiefly in plantsOils and waxes -- found chiefly in plants Oils are liquid at room temperature, waxes are solidsOils are liquid at room temperature, waxes are solids Lipids along with proteins are key components of cell membranesLipids along with proteins are key components of cell membranes

PROTEINS contain the elements carbon, hydrogen, oxygen, and nitrogencontain the elements carbon, hydrogen, oxygen, and nitrogen composed of MANY amino acid subunitscomposed of MANY amino acid subunits It is the arrangement of the amino acid that forms the primary structure of proteins.It is the arrangement of the amino acid that forms the primary structure of proteins.

AN R GROUP IS ANY GROUP OF ATOMS – THIS CHANGES THE PROPERTIES OF THE PROTEIN!

Major Protein Functions Growth and repairGrowth and repair EnergyEnergy Buffer -- helps keep body pH constantBuffer -- helps keep body pH constant

Dipeptide formed from two amino acid subunitsformed from two amino acid subunits Formed by the process of Dehydration SynthesisFormed by the process of Dehydration Synthesis amino acid + amino acid dipeptide + wateramino acid + amino acid dipeptide + water

Hydrolysis of a dipeptide Breaking down of a dipeptide into amino acidsBreaking down of a dipeptide into amino acids dipeptide + H2O ---> amino acid + amino aciddipeptide + H2O ---> amino acid + amino acid

Polypeptide (protein) composed of three or more amino acids linked togethercomposed of three or more amino acids linked together Examples of proteins include insulin, hemoglobin, and enzymes.Examples of proteins include insulin, hemoglobin, and enzymes. ** There are an extremely large number of different proteins.** There are an extremely large number of different proteins.

NUCLEIC ACIDS in all cellsin all cells composed of NUCLEOTIDEScomposed of NUCLEOTIDES store & transmit heredity/genetic informationstore & transmit heredity/genetic information Nucleotides consist of 3 parts:Nucleotides consist of 3 parts: 1. 5-Carbon Sugar1. 5-Carbon Sugar 2. Phosphate Group2. Phosphate Group 3. Nitrogenous Base3. Nitrogenous Base

DNA (deoxyribonucleic acid) contains the genetic code of instructions that direct a cell's behavior through the synthesis of proteinscontains the genetic code of instructions that direct a cell's behavior through the synthesis of proteins found in the chromosomes of the nucleus, mitochondria & chloroplast (plant)found in the chromosomes of the nucleus, mitochondria & chloroplast (plant)

Enzymes and Enzyme Action catalyst: inorganic or organic substance which speeds up the rate of a chemical reaction without entering the reaction itselfcatalyst: inorganic or organic substance which speeds up the rate of a chemical reaction without entering the reaction itself enzymes: organic catalysts made of proteinenzymes: organic catalysts made of protein most enzyme names end in -asemost enzyme names end in -ase enzymes lower the energy needed to start a chemical reaction. (activation energy)enzymes lower the energy needed to start a chemical reaction. (activation energy) can be destroyed by high temperaturescan be destroyed by high temperatures very specific: one enzyme for one reactionvery specific: one enzyme for one reaction

How do enzymes work? substrate: molecules upon which an enzyme actssubstrate: molecules upon which an enzyme acts the enzyme is shaped so that it can only lock up with a specific substrate moleculethe enzyme is shaped so that it can only lock up with a specific substrate molecule ‘Lock & Key” ‘Lock & Key” enzyme enzyme substrate > product

"Lock and Key Theory" each enzyme is specific for one and ONLY one substrate (one lock - one key)each enzyme is specific for one and ONLY one substrate (one lock - one key) this theory has many weaknesses, but it explains some basic things about enzyme function this theory has many weaknesses, but it explains some basic things about enzyme function

Factors Influencing Rate of Enzyme Action 1. pH - the optimum (best) in most living things is close to 7 (neutral) high or low pH levels usually slow enzyme activityhigh or low pH levels usually slow enzyme activity a few enzymes (such as gastric protease) work best at a pH of about 2.0a few enzymes (such as gastric protease) work best at a pH of about 2.0

2. Temperature - strongly influences enzyme activity optimum temperature for maximum enzyme function is usually about F.optimum temperature for maximum enzyme function is usually about F. reactions proceed slowly below optimal temperaturesreactions proceed slowly below optimal temperatures above 104 F most enzymes are denatured (change in their shape so the enzyme active site no longer fits with the substrate and the enzyme can't function)above 104 F most enzymes are denatured (change in their shape so the enzyme active site no longer fits with the substrate and the enzyme can't function)

3. Concentrations of Enzyme and Substrate ** When there is a fixed amount of enzyme and an excess of substrate molecules -- the rate of reaction will increase to a point and then level off.** When there is a fixed amount of enzyme and an excess of substrate molecules -- the rate of reaction will increase to a point and then level off.