Variation in C skeletons contributes to diversity of organic moleculesStraight, branched, closed rings, some have double bonds, triple
Isomers• molecules w/ same molecular formula (same number and kinds of atoms) but diff atom arrangements (which atoms are attached to which and how) Classes of isomers: structural, geometric, enantiomers
Geometric isomers = share same covalent partnerships, butdiffer in their spatial arrangements.• Result from fact that double bonds will not allow the atomsthey join to rotate freely about the axis of the bonds.• Subtle differences affects biological activity.
• Enantiomers = mirror images of each other.• Can occur when 4 diff atoms or groups of atoms are bonded to the same carbon (asymmetric carbon).• 2 diff spatial arrangements of the four groups around the asymmetric carbon. These arrangements are mirror images.• Usually one form is biologically active and its mirror image is not.
Functional Groups• contribute to molecular diversity of life• frequently bonded to carbon skeleton of organic molecules.• Have specific chemical and physical properties.• Are the regions of organic molecules which are commonly chemically reactive.• Behave consistently from one organic molecule to another.• Depending upon their number and arrangement, determine unique chemical properties of organic molecules in which they occur.
Hydroxyl- OH• polar group• Conveys water solubility• Organic compounds with hydroxyl groups are called alcohols.
Carbonyl Group-C=O• polar group• Conveys water solubility.• found in sugars.• at the end of skeleton called aldehyde.• at the middle of skeleton called ketone
Carboxyl Group• polar group• Conveys water solubility• Since it donates protons, has acidic properties.• Compounds w/ this group are called carboxylic acids.
Amino Group• polar group• Conveys water solubility• Acts as weak base. The unshared pair of electrons on the nitrogen can accept a proton, giving it a +1 charge.• Organic compounds w/ this group are called amines.
Sulfhydryl Group• Help stabilize the structure of proteins.• Organic compounds with this functional group are called thiols. What other functional groups do you see in this molecule? Could this molecule have an enantiomer isomer? How do you know?
Phosphate Group• Loss of two protons leaves phosphate group w/ a - charge.• Has acid properties since it loses protons.• Polar group• Conveys water solubility• Important in cellular energy storage & transfer
Methyl Group• Non polar• Conveys hydrophobic properties
Some basicsPolymer – long molecule consisting of many similar or identical building blocks linked by covalent bondsMonomer -
How do the bonds b/t monomers form?Condensation rx or dehydration synthesis – removal of water from monomersFacilitated by enzymes – speed up the rx
How do the bonds b/t monomers break?Hydrolysis – bonds broken by addition of waterHydro = waterLysis = breakEx: digestionEnzymes facilitate
Diversity of macromolecules26 letters make many words40-50 monomers make many macromoleculesKey is in arrangement of monomersTac Act Cat
Carbohydrates• Function – fuel & building mat.• Sugars & their polymers• simplest are monosaccharides or simple sugars.• Disaccharides (double sugars) consist of 2 monosaccharides joined by condensation reaction.• Polysaccharides - polymers of many monosaccharides.
monosaccharides• some multiple of the unit CH2O.• Ex: glucose = C6H12O6.• Funcitonal groups: carbonyl group (>C=O) and multiple hydroxyl groups (—OH).• names end in -ose.•
Diversity of monosaccharides• classified by # of carbon atoms in skeleton (3-7)• Some are enantiomers of each other - spatial arrangement of their parts around asymmetric C atoms. Structural isomers enantiomers
Monosaccharides cont…• most form rings in aqueous solutions.• major nutrients for cellular work.
Disaccharides• glycosidic linkage to form a disaccharide via dehydration.• Maltose - joining 2 glucose• Sucros- joining glucose & fructose.• Lactose - joining glucose & galactose.
Polysaccharides - storage• Function in storage & structural roles.• 100s – 1000s of monosaccharides joined• Starch - plant storage polysac composed entirely of glucose monomers.• Plants store surplus glucose as starch granules within plastids, including chloroplasts & withdraw as needed for E or C.• Glycogen – animal storage polysac. Store 1 day supply in liver & muscles
Polysaccharides - structural• Cellulose – plant structural polysac - major component of cell walls – most abundant organic compound on Earth. – Like starch, cellulose is polymer of glucose. However, the glycosidic linkages in these two polymers differ. – Digestion... Symbiotic orgs• Chitin – animal structural polysac - found in the exoskeletons of arthropods – also provides structural support for cell walls of fungi.
Lipids• Consist mostly of hydrocarbon• Little – no affinity for H2O (water insoluble)• Not polymers• 3 families – Fats – Phospholipids – Steroids
Fats• Glycerol & & fatty acid• Dehydration synthesis• Linkage – ester• Vary in length & the # & location of double bonds• Functions: – E storage – Cushions organs – Insulates body
2 main types of fats1. Saturated – saturated w/ H; no double bonds – Animal fats – Solid @ room temp… why? – Contribute to arteriosclerosis Yum !
2 main types of fats2. Unsaturated – not saturated w/ H; has double bonds Creates kink in shape @ double bond Liquid @ room temp Plants & fish Peanut butter? Why solid?
Phospholipids• 1 glycerol• 2 fatty acids• 1 phosphate group
Phospholipids• Amphipathic• Major component of cell membranes• Structure determines function
Steroids• C skeleton consisting of 4 interconnected rings.• Vary based on functional groups• Cholesterol – imp. In membranes of animal cells – Most other steroids made from it
Proteins!• large• funcitons: – Structure (silk) – Storage (casein) – Movement (actin & myosin) – Defense (antibodies) – Regulation of metabolism (enzymes) – Transport (hemoglobin) – Communication (hormones) – receptor proteins
basics• Monomer – amino acids (20 diff) – Vary based on R groups – Structure of aa – Linkage – peptide bond – Backbone – Aka polypeptide
Condensation reaction or dehydration synthesis
Conformation = 3 D shape of a protein moleculeShape determines functionDNA codes for the type of aa & what order they’re bonded inSo…DNA codes for which proteins you make & which proteins you make determines your physical characteristics
Proteins are so complex that we describe theirstructure on 4 levels 1. Primary structure • the seq of aa • Det by DNA • Sanger, insulin
Proteins are so complexthat we describe their structure on 4 levels2) Secondary structure• Pattern of folds & coils that result from the H-bonding at regular intervals along the polypeptide backbone.• 2 types: alpha helix & pleated sheet
Proteins are so complex that we describe their structure on 4 levels3) Tertiary structure• Irregular contortions that result from bonding b/t R groups of the aa• Types of bonds that can occur b/t R groups: – H-bonds, disulfide bridges, ionic, hydrophobic interactions
Proteins are so complex that we describe their structure on 4 levels4) Quaternary structure• Only those composed of 2 or more polypeptide chains• Overall structure that results from the aggregation of polypeptide chains
Emergent property?Specific function of a protein arises from the architecture of the molecule
Denaturation?• Loss of conformation of a protein• Causes? High temps, change in salt concentration, change in pH