Molecules of Life

Molecules of Life Carbohydrates Monomer-monosaccharides energy supply Proteins Monomer-amino acids structural components Lipids Monomer-fatty acids structural components, energy, hormones Nucleic acids Monomer-nucleotides DNA-genetic material

Composition of Molecules of Life most are carbon based organic compounds unique to living systems with exception of CO2 & carbides carbon is necessary for life electroneutral never loses or gains electrons always shares or forms covalent bonds

H | H--C--H | H Covalent Bonding carbon can form 4 covalent bonds with other elements or with itself has 4 electrons in outermost shell makes each carbon atom a connecting point from which another molecule can branch in four directions

Covalent Bonding since carbon can bind to itself has capacity to construct endless numbers of carbon skeletons varying in size & branching patterns

Organic Compounds chain of carbons in organic molecule-carbon skeleton branched or unbranched double or single bonds straight or arranged in ring form each has unique 3-D shape properties depend on carbon skeleton & atoms attached to skeleton groups of atoms participating in chemical reactions- functional groups H | C ||| C | H

Functional Groups OH- (hydroxyl) C=O (carbonyl) COOH (carboxyl) NH2 (amino) SH-sulfhydryl group PO3 (phosphate) Phosphate group

Classes of Molecules & Functional Groups COOH & NH2- amino acids hydroxyl groups-alcohols carboxyl groups-carboxylic acids-acetic acid sugars contain both-carbonyl group & several hydroxyl groups phosphate groups-found on nucleic acids

Macromolecules 4 main classes macromolecules or polymers consist of many identical or similar molecular units strung together monomers monomers are linked in anabolic reactions dehydration synthesis chemical reaction which removes water broken down into constituent monomers by adding water catabolic reactions-hydrolysis

Carbohydrates composed of C, H & O 1:2:1 ratio Formula: (CH2O)n may contain nitrogen, phosphate and/or sulfur Monomers-monosaccharides simple sugars building blocks for all other carbohydrates 2-10 monosaccharides-oligosaccharide hundreds-polysaccharide. hydrophilic water loving larger molecules are less soluble in water Glucose

Monosaccharides simple sugars single chain or ring of 3-7 carbons named for number of carbons 5 -pentoses 6 -hexoses glucose contains 6 carbons-hexose formula-C6H1206 most important metabolic fuel in body broken downATP + CO2 fructose-6 carbon monosaccharide same formula as glucose fructose & glucose are isomers chemical compounds with same molecular formula but with elements arranged in different configurations Galactose-isomer of glucose & fructose Glucose Galactose Fructose

Disaccharides double sugars covalent bond- between hydroxyl groups of two simple sugars Sucrose Glucose + fructosesucrose + H2O Lactose-found in milk of mammals disaccharide of galactose & glucose Maltose major degradation product of starch composed of 2 glucose monomers too large to pass through cell membranes must be broken down into constituent parts by hydrolysis Sucrose + H20 glucose + fructose

Polysaccharides complex carbohydrates dehydration synthesis reactions add more monosaccharides polysaccharides most in nature are in this form fairly insoluble make perfect storage molecules Glycogen major stored carbohydrate in animal liver & muscle cells highly branched at about every 8-10 residues Starch major form of stored carbohydrate in plants Structure-identical to glycogen-less branching at every 20-30 residues Cellulose found in plants most abundant compound on earth cannot be digested by humans

Lipids contain mostly C & H 1:2 ratio also contain oxygen but less than carbohydrates often have N, S & phosphorous hydrophobic do not dissolve in water include neutral fats, phospholipids & steroids

Lipid Functions structural components of biological membranes cholesterol, phospholipids & glycolipids help form & maintain intracellular structures energy reserves provide 2X as much energy as carbohydrates compose some hormones & vitamins-steroids lipophilic bile acids important for lipid solubilization

Lipids fatty acids-long-chain hydrocarbon molecules composed of fatty acids & glycerol fatty acids-long-chain hydrocarbon molecules hydrocarbon chains make lipids nonpolar and therefore insoluble in water fat synthesis involves attaching 3 fatty acid chains to one glycerol by dehydration synthesis-producing triglycerides glycerol is always the same; fatty acid composition varies length of neutral fat’s fatty acid chains & degree of saturation determine how solid a fat is at room temperature saturated fatty acids with no carbon to carbon double bonds unsaturated have double bonds monounsaturated fats have one unsaturated bond polyunsaturated fats have multiple unsaturated bonds double bonds make for lower melting points presence of unsaturated fatty acids makes fat liquid at room temperature

Hydrolysis of Triglycerides Hydrolysis breaks triglycerides fatty acid + glycerol

Proteins C, H, O, N & small amounts of S & sometimes phosphorous monomer-amino acids 1-7-peptide up to 100- polypeptide more than 100- protein

Proteins most abundant organic compounds in human body provide support for cells, tissues & organs and create a 3-D framework for body contractile proteins allow for movement via muscle contractions transport proteins carry insoluble lipids, respiratory gases & minerals in blood serve as buffers; help to prevent dangerous pH changes enzymes are proteins important in metabolic regulation needed to speed rate of chemical reactions protein hormones coordinate, control & influence metabolic activities of nearly every cell important for defense skin, hair, & nails protect underlying tissues from environment antibodies protect us from disease clotting proteins protect from us from bleeding out

Amino Acids 20 in nature (excluding proline) contain carboxylic acid-COOH & amino-NH2 or amine group functional groups are attached to same carbon atom R group attaches to same carbon amino acid is distinguished by its particular R-group 2 broad classes based upon whether R-group is hydrophobic or hydrophilic hydrophobic repel aqueous environments reside predominantly in interior of proteins hydrophilic amino acids interact with aqueous environments & often form H-bonds found predominantly on exterior of proteins

Protein Structure Primary Secondary Tertiary Quaternary

Structure & Function structure determines function shape of protein allows it to carry out specific duties proteins whose job is to fill in a space (active site) on another molecule-globular in shape those that make up something like muscles or tendons-fibrous shapes depend on environmental characteristics ionic composition, pH & temperature non homeostatic change in any of these will denature protein denaturation causes protein to lose shape loss of shapecannot function properly

Nucleic Acids largest, organic molecules C, H, O, N, & phosphorous nucleotides monomer for nucleic acids provide directions for building proteins 2 main types RNA translates DNA code DNA contains genetic information that is inherited from our parents

Nucleic Acids RNA DNA single polynucleotide chain double helix form two polynucleotide chains wrapped around one another

Nucleic Acids mono-, di-, & tri-phosphorylated forms often abbreviated mono, di- & tri-phosphorylated forms of adenosine are abbreviated AMP, ADP & ATP phosphate bonds are high energy bonds contain energy when broken yield 7kcals ATP ADP + Pi + energy ATP-energy currency of all cells