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46 Cards in this Set
- Front
- Back
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Fatty acids
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-long carbon chains with a carboxylic acid end
3 basic functions: 1. serve as hormones and intracellular messengers in the human body 2. components of phospholipids and glycolipids of cell membranes 3. act as fuel for the body -stored in the body as triglycerides -typical pH is 4.5, most exist as anion form in cellular environment -nonpolar b/c carbon chain predominates -enter into the Kreb's cycle 2 C's at a time. |
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Lipolysis
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-A process by which triacylglycerols are hydrolyzed to form glycerol and the corresponding fatty acids.
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Saponification
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-triacylglycerols can be cleaved by the addition of NaOH
-the production of soap |
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Tryacylglycerols
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-Fatty acids are stored as triacylglycerols in adipose cells
-Lypolysis results in a glycerol and 3 fatty acids |
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Amino acids
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-the building blocks of proteins
-strung together with peptide bonds to form proteins -10 amino acids are essential, meaning they must be ingested. -An amino acid with no ionizable substituents on its R group will be a diprotic acid |
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Peptide bond
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-links amino acids together to form polypeptides
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Amide
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An amine connected to a carbonyl carbon
The functional group of an amino acid |
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The formation of peptide bonds
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-Formation forms an amide via condensation of two amino acids.
-One amino acid looses a hydroxyl, one amino acid looses a hydrogen and the bond is formed (loose 1 H2O) |
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Isoelectric point, pI
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-The pH arrived at thru titration at which 100% of the amino acid has lost the H on its carboxylic acid.
-pI is dictated by the side group of an amino acid. The more acidic the side group, the lower the pI, the more basic the side group, the greater the pI. |
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The only 3 basic amino acids
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1. histidine
2. arginine 3. lysine |
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Carbohydrates
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-Made up of carbon and water
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Hexoses
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-6 carbon carbohydrates
-Typically show up as fructose or glucose -Glucose is an aldehyde and fructose is a ketone. |
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Aldose
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-Polyhydroxyaldehydes like glucose
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Ketose
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-Polyhydroxyke-tones like fructose
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Aldohexose
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-A molecule that is both a hexose and contains an aldehyde like glucose.
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D and L conformation
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-if the hydroxyl group on the highest numbered chiral carbon points to the right, the carbohydrate is labelled D.
-if points left, the carbohydrate is labelled L |
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Anomeric carbon
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-The only carbon attached to two oxygens
-can point either upwards or downwards resulting in an alpha or beta anomer. |
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Furanose
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-a five-membered carbohydrate ring
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Pyranose
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-A six-membered carbohydrate ring
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Glucopyranose
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-a glucose ring.
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Sugars: ose vs. oside
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-sugars with -ose ending are reducing sugars, contain an OH on anomeric C
-sugars with -oside are non-reducing sugars, contain -oCH3 on anomeric C |
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Sucrose
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-1,1' glycosidic linkage: glucose and fructose.
-linkage is alpha with respect to glucose and beta with respect to fructose. |
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Maltose
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alpha-1,4' glucosidic linkage: two glucose molecules.
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Lactose
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alpha-1,4' galactosidic linkage: galactose and glucose.
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Cellulose
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Beta-1,4' glucosidic linkage: a chain of glucose molecules
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Amylose
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alpha-1,4' glucosidic linkage: a chain of glucose molecules
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Amylopectin
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-alpha-1,4' glucosidic linkage: a branched chain of glucose molecules with alpha 1,6' glucosidic linkages forming the branches
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Glycogen
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-alpha-1,4' glucosidic linkage: a branched chain of glucose molecules with alpha 1,6' glucosidic linkages forming the branches.
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NMR: chemical shift
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-Hydrogens on an NMR have varying chemical shifts according to how well they are shielded.
-Hydrogens appearing upfield are well shielded, typically near electron donating groups. Hydrogens appearing downfield are not well shielded, typically near electron withdrawing groups. |
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NMR: splitting
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-Splitting results from neighboring Hydrogens that are not chemically equivalent.
-Number of peaks due to splitting for a group of chemically equivalent hydrogens is given by the formula n+1 where n is the number of neighboring hydrogens that are not chemically equivalent. |
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NMR aldehyde proton shift
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9.5 ppm
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IR spectroscopy: Infrared radiation
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-the direction of the electric field oscillates, cauising the positive and negative centers within polar bonds to move toward each other and then away from each other.
-When exposed to IR, the polar bonds within a compound stretch and contract in a vibrating motion. |
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IR Spectroscopy
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-An infrared spectrometer slowly changes the frequency of infrared light shining upon a compound and records the frequencies of absorption in reciprocal centimeters (number of cycles per cm).
-When the resonance frequency of the oscillating bond is matched by the frequency of IR, the IR energy is absorbed. |
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Predictions about molecule mass via IR spectroscopy
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-atoms with greater mass resonate at lower frequencies; stiffer bonds, such as double and triple bonds resonate at higher frequencies
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IR spectroscopy: fingerprint region
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-Many of the complex vibrations that distinguish one compound from a similar compound are found in the 600 to 1400 cm-1 range
-unique to nearly all compounds. |
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UV spectroscopy
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-detects conjugated double bonds by comparing the intensities of two beams of light form the same monochromatic light.
-wavelength is between 200-400 nm. - |
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UV spectroscopy: factors affecting the wavelength of a compound
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-each additional double bond increases the wavelength by about 30 to 40 nm.
-An additional alkyl group attached to any one of the atoms involved in conjugated system increases the spectrum wavelength by about 5 nm. -Isolated double bonds do not increase the absorption wavelength. |
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Beta-carotene
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-a precursor of vitamin A with 11 conjugated double bonds
-absorb visible light, show up in the visible spectrum (emits orange, absorbs blue and green). |
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When is a compound part of the visible spectrum?
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-If a compound has 8 or more double bonds, its absorbance moves into the visible spectrum.
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Mass spectrometry
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-gives the molecular weight and molecular formula of a compound.
-molecules are bombared with electrons, causing them to break apart and ionize. -the ions are accelerated through a magnetic field. -radius of curvature depends on mass to charge ratio- if high, the molecule will not bend as much, if low, the molecule's path will bend more. |
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Mass spectrometry: parent peak
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-the peak made by the molecular ions.
-made by molecules that did not fragment. -will be all the way to the right on the spectrum -has an abundance of 10 b/c it is 10% as high as the base peak. |
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Mass spectrometry: base peak
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-the largest peak on the spectrum.
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Chromatography
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-resolution of a mixture by passing it over or through a matrix that absorbs different compounds with different affinities, ultimately altering the rate at which they loose contact with the resolving matrix.
-the compound with a greater affinity for the surface will move more slowly. -typically the more polar solvent will elute more slowly b/c they have a greater affinity for the stationary phase. |
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Distillation
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-Separation based on vapor pressure.
-A solution of two volatile liquids with boiling point differences of approx. 20C or more may be separated by slow bowling. -The compound with the lower bp will boil off first and can be captured and condensed in a cool tube |
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crystallization
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-based on the principle that pure substances form crystals more easily than impure substances
-pure water forms crystals more easily -crystalization of most salts is exothermic. |
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Extraction
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-based upon solubility due to similar polarities.
-organic mixture is on top of aqueous layer 3 steps: 1. add strong acid and shake. Acid protonates bases like amines in the organic layer, making them polar. The polar amines dissolve in aqueous layer and are drained off. 2. Add a weak base. Deprotonates only the strong acids like carboxylic acids, making them more polar. Polar carboxylic acids dissolve in aqueous layer and are drained off. 3. Add a strong base. Strong base reacts with rest of acids. Dissolve in aqueous layer and drained off. |
