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EK Orgo 4
biochem and lab tech
| Question | Answer |
|---|---|
| carbonyl (C=O bond) IR | 1710, sharp peak |
| carboxylic acid O-H bond IR | 2500-3500, broad peak |
| aldehyde C-H bond IR | 2700, 2800 sharp-ish peak |
| saturated C-H bond IR | 2800-3000 sharp-ish peak |
| alcohol O-H bond IR | 3300, deep med broad peak |
| amine N-H bond IR | 3300 short broad peak |
| nitrile C=-N bond IR | 2200 sharp peak |
| amide N-H bond iR | 3300 sharp-ish peak |
| IR spectroscopy | used to identify which functional grps are in a camped but can't show the shape or size of carbon skeleton (they vibrate at resonance frequency when exposed to infrared radiation) |
| proton nmr spectroscopy steps | (1) ID chem eq H's (2)ID/count neighboring H's that are not chem eq. Use n+ 1 to figure the number of peaks created by splitting for chem eq H's (3)ID e' withdrawing/donating groups near chem eq. H's (withdrawing move left) |
| aldehyde protons in NMR | 9.5ppm |
| nmr spectrum | each peak represents chemically equivalent hydrogen and splitting of peaks is created by neighboring H's |
| nuclear magnetic resonance spectroscopy | NMR, most studied with H nucleus, looks at energy absorption of nucleus in resonance when exposed to electromagnetic radiation |
| spin-spin splitting | results from neighboring H's that are not chemically equivalent, where |
| fingerprint region of IR spectroscopy | 600 to 1400 cm-1, region where the complex vibrations distinguish 1 camped from a similar one |
| UV spectroscopy | provides info on conjugated portion of cmpd, starts at 217 nm with butadiene |
| rules for UV spectroscopy | each additional conjugated bond adds 30-40 nm to max wavelength and each additional alkyl group adds 5 nm, isolated dbl bonds do NOT increase absorption wavelength |
| if a cmpd has more than 8 double bonds… | its absorbance moves into visible spectrum |
| mass spectroscopy | gives MW and sometimes molecular formula |
| MS theory | molecules bombarded with e's, causing them to break apart and ionize & these ions are accelerated thru magnetic field to deflect ions around a curved path and passage ions at different times |
| mass to charge ratio | (m/z) what determines the path in magnetic field in MS |
| parent peak in MS | the peak made by molecular ions |
| peaks in MS | assigned abundances as %'s of the base peak |
| chromatography | separation of mixture by passing it over or thru matrix that adsorbs diff cmpds with diff affinities where cpm's in the mixture that have a greater affinity for surface move more slowly |
| mobile phase | usually what the soln that will be separated by chromatography is dissolved in |
| stationary phase | surface that adsorbs the cmpds from the mixture |
| column chromatography | soln containing mixture is dripped down column containing solid phase (usually glass) where polar are usually more slowly |
| paper chromatography | sample is spotted on paper, then other end is placed in solvent that moves up paper thru capillary action - more polar cpm's in sample move slower bc they are attracted to polarity of paper |
| thin layer chromatography | similar to paper chromatography except coated glass or plastic plate is used instead paper |
| gas chromatography | liquid phase is stationary phase, mobile phase is gas that is heated and passed over liquid phase in column and the cmpds in mixture will equilibrate with liquid phase at diff rates |
| distillation | separation based on vapor pressure where cmpd with lower bp (higher VP) will boil off and be captured |
| ebulliator | introduces small air bubbles into system which break the surface tension of liquid behind heated and prevented superheating and bumping -- similar to boiling chips for distillation at atmospheric pressure |
| crystallization | pure substances form crystals more easily than impure substances, inefficient method of separation |
| extraction | separation based on solubility due to similar polarities |
| 3 steps of extraction | (1)strong acid - protonates bases in organic layer and makes them polar which can dissolve aq (2)weak base -deprotonates strong acids to make them polar & then dissolve aq (3)strong base - reacts w/ rest of acids to make them polar & dissolve aq |
| what is the order of cmpds removed in extraction? | amines (bases), carboxylic acids (strong acids), then phenol (weak acids) |
| fatty acids | long carbon chains with carboxylic acid end, highly reduced so they store a lot of energy and oxidize 2 carbons at a time into Krebs cycle |
| 3 functions of fatty acids in human body | (1)hormones and intracellular messengers (2) part of phospholipids and glycolipids of cell membranes (3) fuel for body |
| lipolysis | process where triacylglycerols (how fatty acids stored) are hydrolyzed to form glycerol and corresponding acid (REVERSE OF ESTERIFICATION) |
| saponification | process where triacylglycerols cleaved by addition of NaOH to form soap |
| alpha carbon in fatty acid | carbon next to carbonyl |
| omega carbon in fatty acid | carbon at opposite end of fatty acid chain (from carbonyl) |
| how many amino acids are essential? | ten- these cannot be synthesized by the body and must be ingested |
| isoelectric point | pI, this is the PH were the population has no net charge and the max |
| carbohydrates | Cn(H2O)n, most likely on MCAT fructose or glucose |
| hexoses | six carbon carbohydrates, appear as Fischer projections or right structures |
| aldose | polyhydroxyaldehyde, ex: glucose |
| ketoses | polyhydroxyketone, ex: fructose |
| D carbohydrate Fischer projection | hydroxyl on the highest numbered chiral carbon points to right |
| L carbohydrate Fischer projection | hydroxyl on the highest numbered chiral carbon points to left |
| anomeric carbon | onlyC attached to two O's (when the chiral carbon with OH attacks carbonyl) |
| alpha anomer | OH group on anomeric carbon is pointing downward |
| beta anomer | OH group on anomeric carbon is pointing upward |
| glycoside | sugars that are not acetals (ex: replacing OH group on anomeric carbon with OCH3 grp) |
| reducing sugars end in… | -ose |
| nonreducing sugars end in | -oside |
| tollens reagent | basic reagent that detects aldehydes and ketones (reduced by aldoses and ketoses but not glycosides even tho they are closed ring acetals bc they need to be in the open form) |
| when will a dissacharade or polysaccharide reach with tollens reagent? | if there is anomeric carbon that is not involved in glycosidic bond and is free to react |
| sucrose | 1,1' glycosidic linkage of glucose and fructose |
| maltose | alpha-1,4' glucosidic linkage of 2 glucose |
| lactose | beta-1,4' galactosidic linkage of galactose and glucose |
| cellulose | beta-1,4' glucosidic linkage of glucose chain |
| amylose | alpha-1,4' glucosidic linkage of glucose chain |
| amylopectin | alpha-1,4' glucosidic linkage: branched chain of glucose with alpha-1,6'glucosidic linkages forming branches |
| glycogen | alpha-1,4' glucosidic linkage: branched chain of glucose w/ alpha-1,6' glucosidic linkages forming the branches |
| how are glycosidic linkages broken? | via hydrolysis + enzyme (otherwise will be too slow) |
| how does partial bond character of peptide bond effect structure of enzyme? | AA's bias shape of 2ary structure bc of the rigid structure of the peptide bond where dbl bond prevents rotation-- steric constraint on H bond formation |
| saturated fats have higher or lower heats of combustion than unsaturated? | higher |
| what functional groups on R group of AA increase solubility? | carboxylic acids and amines |
| important fact of proline | interrupts 2ndary structures bc amide nitrogen has no hydrogen to contribute to H bonding (which drives and stabilizes alpha helix structure; it also induces kink/turn in pP chain that further disrupts H bonding |
| azeotrope | mixture of two or more liquids in a ratio that its composition cannot be separated by simple distillation - distillation will not work here |
Created by:
miniangel918
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