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Molecules of Life
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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
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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
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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
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Covalent Bonding since carbon can bind to itself
has capacity to construct endless numbers of carbon skeletons varying in size & branching patterns
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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
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Functional Groups OH- (hydroxyl) C=O (carbonyl) COOH (carboxyl)
NH2 (amino) SH-sulfhydryl group PO3 (phosphate) Phosphate group
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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
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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
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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
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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 downATP + 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
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Disaccharides double sugars
covalent bond- between hydroxyl groups of two simple sugars Sucrose Glucose + fructosesucrose + 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
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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 residues Cellulose found in plants most abundant compound on earth cannot be digested by humans
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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
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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
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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
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Hydrolysis of Triglycerides
Hydrolysis breaks triglycerides fatty acid + glycerol
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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
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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
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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
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Protein Structure Primary Secondary Tertiary Quaternary
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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 shapecannot function properly
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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
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Nucleic Acids RNA DNA single polynucleotide chain double helix form
two polynucleotide chains wrapped around one another
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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
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