MCAT UWorld Exam with Complete Solutions

Different Nitrogen names - ANSWER Enamine: C=C-N Amine : C-N Imine: C=N Amide: O=C-N Imide: O=C-N-C=O Ketone(aldehyde) + 1° amine --> Imine Ketone(aldehyde) + 2° amine ---> Enamine think about it when replace the Oxygen of carbonyl and attach NitrogenR, /Make sure It has a lone pair. for the 2 ° amine move double bond to the C. Amine - ANSWER C-N Myopia (nearsighted) - ANSWER *(-)F= diverging mirror /convex mirror/concave lens *convex mirror: image always virtual upright (negative image) Amide - ANSWER Nitrogen bonded to a carbonyl carbon RC=ONH2 or RC=ONR2 Formed by carboxylic acid + Amine (c=0 bond to nitrogen) Enamine - ANSWER Nitrogen bonded to double bonded carbon ex: C=C-N Imine - ANSWER Carbon=Nitrogen Imide - ANSWER consisting of two acyl groups bound to nitrogen (RC=ONRC=OR) Anhydride - ANSWER Contains two carbonyls separated by an oxygen atom, made from condensation of two CAs. Functional groups - ANSWER Amine C-N Imine: C=N Amide O=C-N Imide: R-O=C-N-O=C-R Constitutional isomers - ANSWER Compounds have same molecular formula & different connectivity acetic acid - ANSWER CH3COOH Conformational Isomer - ANSWER Same molecule, differ in rotation around single pi bonds. ex ring to chair conformation. Wedges= substiuent is up/above ring Dash= down/below ring Tautomer - ANSWER relocation of a proton. transer of hydrogen from one position to another within a molecule and movement of a double bond to adjacent atom Enantiomer - ANSWER Specific rotation of equal mag but opposite direction ex: +40 & -40 diff at ALL chiral center (R,R) --> (S, S) seperat by Resolution RACemix mixture - ANSWER Compose 50% of one enantoimer and 50% of another specific rotation of 0 separate by FRACtional Distillation Diastereomers - ANSWER differ at 1+ , not mirror images, differ in magnitude and direction ex: -40 & -25 seperat by fractional distillation Decarboxylation - ANSWER RXN that removes a carboxyl group from a carboxylic acid with a B-carbonyl releasing the carboxyl group as CO2 gas. Isomerase - ANSWER move functional groups WITHIN a molecule Transferase - ANSWER transfer functional groups from one molecule to another ex: A-B +C --> A + B-C kinase( phosphorylation): transfer of a phosphate group from ATP to a specified molecule. phosphorylate AA: STY - serine, threonine, tyrosine - ANSWER Phosphatase: dephosphorylation removes a phosphate group average weight of AA : 110Da/amino acid - ANSWER Average weight of an amino acid? Weight of 288-residue protein? 110Da/amino acid * 288 amino acids = 31,680Da ~ 32kDa Nucleophilic substitution - ANSWER SN1 or SN2 SN1: tertiary LG, form stable carbocation. Carbocation (+C) enhances electrophilicity SN1: two step rxn: 1)LG leaves forming Carbocation (+C) 2) Nu attacks carbocat "Carbocation forms first" SN2: Nu attacks & Carbocation occurs at same time Extraction - ANSWER Organic compounds with acidic or basic functional groups enter the aqueous layer as ionic salts when acids and bases are added to an extraction. Amines are weak bases that require strong acids to be protonated. Phenols are weak acids that are only deprotonated by strong bases. Acids - ANSWER Donate H (protonate) Bases - ANSWER Accept H (deprotonate) , stated in question Base added to reaction THINK it will pull of the most acidic proton. Thermodynamic stable= Spontaneous (release energy) Delta G= (-) Unstable= add energy, break bond, rxn requires energy Stable= hydrolysis of ATP, GTP - ANSWER Kinetic stable= rate, The slower the reaction occurs, the greater the kinetic stability. high Ea unstable= fast rxn Thermodynamically favorable but slow: means break bonds (add energy/ nonspontaneous rxn) and kinetically stable (rate/break slowly) Glucose - ANSWER aldose sugar (C1 contains aldehyde Functional group) thermodynamic enolate - ANSWER -more substituted double bond -higher activation energy (more stable) -Higher rxn temp - forms more stable product - use smaller base ex NaH Reversible rxn =thermo control favor stable product (most neg G) Kinetic enolate - ANSWER -less substitued double bond -Lower activaton energy (less stable) -forms less stable product -lower temp -bulk base (LDA) Irreversible rxn =kinetic control (low temp) = lowest EA, Fastest rxn Spontaneous rxn - ANSWER ΔEo=(+), ΔG°=(-), electrons flow from molecules with low reduction potential to molecules with high reduction potential. NaBH4 - ANSWER selective for Ketones (& Aldehydes) reduces to secondary alcohols. galvanic cell (voltaic cell) - ANSWER spontaneous battery molecular geometry (VSEPR) - ANSWER MG EG 2 SP 180 Linear (CO2) 3 SP2 120 Trig plan (Bf3) Bend (2:) 4 SP3 109.5 Tetrah(Ch4) Trig Pyr (3: Nh3) Bent (2::) (H2O) LiAH4 (reduction) - ANSWER SELECTIVE for ESTERS, & carboxylic acids reduces them to primary alcohols BH3, THF /H3O+ (Borane) - ANSWER selective for carboxylic acids reduce to primary alcohols reducing molecule has lots of H's Reducing agent= It gets oxidized and reduces the other molecule ex. LiAH4. NaBH4. LiAH4 will get oxidized but will reduce the other molecule in the question. - ANSWER Oxidizing Agent = double bonds - ANSWER can take to attach molecule to it Ideal gas - ANSWER -No volume -No attractive/ repulsive forces -Complete elastic collisions -Kinetic energy increases w/ high temp. Ideal gas behavior: HIGH TEMP LOW PRESSURE, IMF, Ideal fluid - ANSWER No viscosity Not compressible Laminar flow Ka - ANSWER KA= Products/ Reactants Larger Ka= indicate greater extent of dissociation in solution. Ka value of polyprotic acid decreases w. each proton that is removed smallest pKa (largest Ka) is the strongest acid and will yield the solution with the lowest pH. pka - ANSWER smaller pka= more acidic pka=-log (ka) pH - ANSWER pH= -1/2 log (HA * Ka) Pka vs PH - ANSWER pKa of a chemical group is the pH at which the ratio of protonated to deprotonated species is 1:1. protonated:deprotonated ratio A decrease in pH yields increased H+ concentration (favors protonation) whereas an increase in pHyields decreased H+ concentration (favors deprotonation).Decreasing the`` pKa yields a higher proportion of protonated species, and increasing the pH yields a lower proportion. Each pH unit above or below the pKa alters the ratio of protonated to deprotonated species by a factor of 10 Half equivalence point - ANSWER >Buffered >pH=pKA *50% HA, 50% A- **Conc Acid= Conc BASE ( 50 prot, 50 deprot) Horizontal line equivalence point of a titration - ANSWER >vertical line | **moles of acid = moles of base > Acid add base, added enough base to deprotonate every single acid molecule (100%A-) Acid in deprotonated form pI value - ANSWER PI=pH at which the net charge on the protein is zero. For a protein with many basic amino acids, the pI will be high, while for an acidic protein the pI will be lower. Hyperventilation - ANSWER increase blood PH (basic) and decreases HCO3- levels. Removal of CO2 shifts the rxn to the left to maintain equilibrium Vmax - ANSWER Vmax=kcat[E], Vmax directly proportional to enzyme concentration. Increase Vmax= Increase Enzyme conc. Endergonic= nonspontaneous (ΔG=+), add energy - ANSWER Exergonic= spontaneous (ΔG=(-), release energy Anion exchange resin - ANSWER (+) beads bind the negative charge Kd - ANSWER Low Kd Value= High tendency for complex to remain bound, high binding affinity. High Kd= low binding affinity, annhydride - ANSWER starting with the most reactive: acyl halides > anhydrides > esters and acids > amides. Thioether - ANSWER R-S-R thioether group contains a sulfur atom single-bonded to two carbon atoms (C-S-C). Ionic radius - ANSWER (+) <Neutral < (-) K+, Ar, and Cl- have the same number of electrons, but K+ has the most protons. These exert an attractive force on the electrons, giving K+ the smallest radius Note that K has one more electron than K+ and would thus be larger. covalent bond - ANSWER involve sharing of electrons between two atoms and are the type of bond that link atoms together within a molecule noncovalent: bond large molecules(molecule to molecules) such as proteins and nucleic acids ex: hydrogen bonds, ionic bonds, hydrophobic, vanders. GAIN electron - ANSWER move to the right of periodic table Fractional distillation - ANSWER separate by diff less than 25C. SDS - ANSWER disrupts only noncovalent bonds, separate proteins based on molecular weight (size), can be useful in determining whether disulfide bonds contribute to the tertiary structure of a protein. under Reducing Conditions, a reducing agent (eg, 2-mercaptoethanol) is added to disrupt disulfide bridges, allowing each subunit to separate as individual polypeptides. Glucose - ANSWER tautomerization - ANSWER relocation of a proton Z= cis same side of DOUBLE BOND - ANSWER E= trans opposite side of DOUBLE BOND mnemonics= enemies are opposite BIOLOGYYYYYYYYYY - ANSWER Parvo cellular pathway: Shape , spatial resolution. - ANSWER Magnocellular resolution: Temporal resolution (Motion) Nonsense mutation - ANSWER premature stop codon " Stop the nonsense" citrate, isocitrate, (alpha)-ketoglutarate, succinyl-CoA, Succinate, fumarate, malate, oxaloacetate "Can I Keep Selling Sex For Money Officer"? - ANSWER List the order of citric acid cycle compounds Galactose is a epimer of Glucose... glucose is an aldohexose. So the main difference between Glucose and Galactose is Carbon 2 non-anomeric carbons differing in up/down in ring or Right/Left on Haworth galactose: 6c aldose - ANSWER ACetylation: reduces positive charge of histone neutralise positive lysine decreasing attraction btw histone (+) and DNA (-) - ANSWER analogous structures - ANSWER share same fxn ( wings of bee= wing bird) Homolog structure= alDosTerone - ANSWER Increase sodium reabsorption in the Distal Tubule , also cause water reabsport Aldo release from Adrenal cortex when low BP. increaese Na reabp in distal and collecting. upreglated the na/k pumps. (3na out/2 k in nephron away from blood) ADH- collecting duct; increase water reabsorption thru increased aquaporin channels in the collecting ducts. Protein metabolism - ANSWER Produce urea as a byproduct Kidney - ANSWER Filteration= glomerulas/ renals Proximal tubule= reabsoorption & secretion Descending loop of hen+ permeable to water Ascending loop of henle= impermeable to water, actively transports sodium into kindey. Loop of henly increase the solute concentration of the medulla, decreasing the solute concentration of the filtrate. AA most phosphorylated - ANSWER eukaryo