AAMC FL 1 FULL REVIEW- Chem/Phys exam questions fully solved & verified for accuracy 2024

In the chromatography of the reaction mixture, water absorbed on cellulose functioned as the stationary phase. What was the principal factor determining the migration of individual components in the sample? A.Hydrogen bonding B.Solute concentration C.Stationary phase concentration D.Thickness of paper B and D are dumb options. Knock them out. hydrogen bonding to the stationary phase will determine the relative rate of migration of the various components in the sample. When thinking migration, think bonding. If it bonds super well, it isn't going to move very far. What assumption is being made if scientists conclude that aspartic acid was formed by the prebiological synthesis in the passage? A.Aspartic acid is unstable at temperatures below 150°C. B.All of the malic acid underwent the dehydration reaction to form fumaric/maleic acid. C.Compound A and cyanide were available on primitive Earth. D.The reaction between ammonia and fumaric acid was catalyzed by the presence of water. POE: D- is wrong. water is not a catalyst B- some of the magic acid was turned to aspartic acid in the next equation. WRONG. A- the 150 degrees comes into play when the scientists are doing the actual experiment, NOT the synthesis. C- passage has right before the figure of the reaction: "scientists have studied the production of amino acids under conditions that simulate those of primitive Earth." ^^^^this indicates that C is the right answer. According to the developed chromatography plate shown below, what is the approximate Rf value of aspartic acid? Rf: distance travelled by analyze/distance traveled by solvent. 2/10---> 0.2 Which of the following statements does NOT correctly describe the dehydration of malic acid to fumaric acid and maleic acid? A.The reaction occurs most readily with tertiary alcohols. B.The reaction involves the loss of a water molecule. C.The reaction has a carbocation intermediate. D.The reaction is stereospecific. NOT is the key word. DEHYDRATION involves: -loss of a water molecule (cross b out) -it does have a carbocation (sn1) -and does like tert substitutions (snl) D is wrong. Two products are made, therefore it is not stereospecific. What type of functional group is formed when aspartic acid reacts with another amino acid to form a peptide bond? A.An amine group B.An aldehyde group C.An amide group D.A carboxyl group C. amide is the other end of the peptide bond! peptide bond= carboxyl group reacts with amine, making a c=o next to an N which is an amide If 2-pentanol replaces 1-pentanol in the reaction shown in Figure 3, the rate of substitution is less because: A.the C-O bond in 2-pentanol is stronger than the C-O bond in 1-pentanol. B.there is a competing elimination reaction that slows the rate of substitution. C.there is more steric hindrance at the oxygen atom in 2-pentanol than in 1-pentanol, making protonation less likely. D.there is more steric hindrance at the 2-position of 2-pentanol than at the 1-position of 1-pentanol. Figure 3 shows an SN2 reaction. You know that SN2 reactions hate steric hinderance. It literally will not go with a tertiary one, but is hella slow with a secondary one. The steric hinderance is not at the oxygen. It's talking about all the other crap. What's important is the Halide being able to attack the carbocation intermediate, which is made more difficult by hinderance from the extra alkyl groups since it's further down the chain The oxygen isn't sterically hindered. Its actually pretty available to be protonated. The carbon however is surrounded by other carbons and hydrogens which increases steric hindrance at that site. Which is actually the only thing that matters since the nucleophile will be attacking that carbon and not the oxygen that presumably already left the molecule as H20. D is correct. Hydride shifts are not DIRECT products. direct products= products without rearrangement. If a solution containing the compounds shown in Figure 4, is injected into a gas-liquid chromatograph, the first peak observed in the gc trace is attributable to which compound? A.2-Methyl-2-butanol B.2-Methyl-2-butene C.2-Chloro-2-methylbutane D.2-Bromo-2-methylbutane Gas chromatography will elute the LIGHTEST molecular weight FIRST. B is the lightest compound Chirality if lowest priority is on a wedge, flip the stereochemistry. if on dash, you gucci In determining which reactant loses the -OH group, which of the following isotopic substitutions would be most useful? A.Replace the acidic H of acetic acid with D. B.Replace the alcoholic H of ethanol with D. C.Replace the carbonyl oxygen of acetic acid with O-18. D.Replace the hydroxyl oxygen of ethanol with O-18. D. this would be the oxygen that is added to the product A person, whose eye has a lens-to-retina distance of 2.0 cm, can only clearly see objects that are closer than 1.0 m away. What is the strength S of the person's eye lens? (Note: Use the thin lens formula 1/O+1/I=S A.-50 D B.-10 D C.51 D D.55 D ***CONVERT EVERYTHING TO METERS FOR LENS MAKER 1/f = 1/o + 1/i S = 1/1 + 1/0.02 1+ (1e0/2e-2) 1+.5e2 1 + 50 = 51 D. Which statement correctly describes how enzymes affect chemical reactions? Stabilization of: A.the substrate changes the free energy of the reaction. B.the transition state changes the free energy of the reaction. C.the substrate changes the activation energy of the reaction. D.the transition state changes the activation energy of the reaction. D!!!! Yes queen. stabilization of the transition state, not the substrate, provides binding energy that is used to lower the activation energy. Which of the following will decrease the percentage ionization of 1.0 M acetic acid, CH3CO2H(aq)? A.Chlorinating the CH3 group B.Diluting the solution C.Adding concentrated HCl(aq) D.Adding a drop of basic indicator C: HCl is a strong acid that will increase the amount of H+ in solution and thus decrease the percentage of CH3CO2H that ionizes. A. Would do the opposite. We know chlorine is a very electronegative atom. That sucker will hog electron density any chance it gets. It will be very good at helping distribute the negative charge produced when deprotonation. This means the conjugate base form will be more stable and preferred. Therefore we can infer adding a Cl leads to an increase in Ionization When the current in the micro-robot's circuit increases and the resistance of the circuit remains constant, the voltage of the circuit: A.decreases. B.increases. C.is constant. D.is zero. B. v=IR Voltage and current are directly proportional! Knowing that the speed of light in the vitreous humor is 2.1 × 108 m/s, what is the index of refraction of the vitreous humor? (Note: The speed of light in a vacuum is 3.0 × 108 m/s.) A.0.7 B.1.4 C.2.1 D.3.0 index of refraction= speed of light/ speed of the other thing 3e8/2e8= 1.5 which is closest to answer choice B The intensity of the radiation emitted by the oxygen sensor is directly proportional to the: A.propagation speed of the radiation. B.wavelength of the radiation. C.polarization of photons emitted. D.number of photons emitted. D. energy of electromagnetic radiation is directly proportional to the number of photons, and the intensity of electromagnetic radiation is defined as energy emitted per unit time. Thus, intensity is directly proportional to the number of photons emitted. What is the energy of the photons emitted by the LED at a frequency of 610 THz? (Note: h = 6.6 × 10-34 J·s) A.9.2 × 10-12 J B.1.6 × 10-16 J C.1.1 × 10-18 J D.4.0 × 10-19 J Multiply the two numbers because... e=Hf h=planks constant f= frequency e=energy (6e-34)(6e14)= 36e-20= 3.6e-19----> closest answer is D. **tetra is e12, but added two more exponents since you started with 610!! What is the relationship between Pp, PMPA, and Pd? A.Pp = PMPA + 3Pd B.Pp = 3PMPA + Pd C.Pp = 3PMPA − 3Pd D.Pp = PMPA − 3Pd Passage: PMPA = Pd + (Ps - Pd)/3 Pp = Ps - Pd c. 3PMPA= Pd+ (Ps-Pd) *you see from the first equation that Pd is directly related to 3PMPA put three in front of it. *also, C is the only answer choice with a -pd answer and a 3pmpa What percentage of standard atmospheric pressure is the pulse pressure of a healthy adult? A.10% B.6% C.2% D.1% Passage: Ps = 120 mmHg and Pd = 75 mm Hg pulse pressure Pp is defined as Pp = Ps - Pd SO. Let's look at this. Pulse pressure is the difference between these two. (120-75)= 45 Standard atmospheric pressure is 760 mm hg. round--->45/760 = 9/152 ~ 9/150 = 3/50 = 6/100 = 6% What fraction of a 15O sample decays in 10 min? A.1/8 B.9/16 C.3/4 D.31/32 Passage: 15O (with a half-life T1/2 = 2 min) There are 5 half-lives in 10 minutes. (1/2)^5=1/32 Only 1/32 will remain of the sample. So, 31/32 of the sample decayed. What is the work generated by a healthy adult who circulates 9 L of blood through the brachial artery in 10 min? A.2 kJ B.12 kJ C.20 kJ D.120 kJ ***want minutes in seconds 9L= 900ml 900ml corresponds to 200w Power= work/time 200w= work/600 seconds 200x600=120,000 120 kj Compared to micellular Compound 1, Compound 2 is structurally more rigid as a result of what type of interaction? A.Intermolecular hydrogen bonding B.Intermolecular covalent bonding C.Intramolecular hydrogen bonding D.Intramolecular covalent bonding Passage: Molecules of Compound 1 spontaneously self-assemble into cylindrical micelles in water at pH 4 but freely redissolve at pH 8. Oxidation of self-assembled, micellular Compound 1 with iodine resulted in a solid material (Compound 2) which is stable in alkaline solutions. B. Since the passage indicates that multiple compound ones are coming together to form compound 2, this question wants to to pick intermolecular forces. (cross out C and D) Oxidation= covalent bonds Think oxidation of cysteine to make disulfide bonds. intermolecular forces forces between molecules intramolecular forces forces within molecules. Which amino acid residues were incorporated into Compound 1 to promote the adhesion of cells on the scaffold surfaces? A.Arg and Gly B.Cys and Gly C.Cys and Asp D.Asp and Arg D. arginine and aspartic acid are actually located in the molecule. adhesion to cells would need an attraction and difference in charge Which amino acid was incorporated into Compound 1 as a future site of covalent attachment to HA prior to mineralization? A.Ser B.Ala C.Tyr D.Thr Passage: (4) a residue that was phosphorylated for future attachment of nanocrystals of HA Only amino acids that can be phosphorylate are threonine and serine. Also, threonine has an extra methyl group sticking out where the phosphate is attached (not seen in the structure) so A! Compound 1 was designed to exhibit pH-dependent self-assembly. What feature(s) of the molecule is(are) responsible for the pH dependence of aggregation (Equation 1)? A.Thiol side chains that can hydrogen bond B.Long alkyl tail that exhibits predominantly London forces C.Side chains whose net charge responds to pH D.Covalent linkages that reversibly hydrolyze C. The answer to this question is C because the molecule contains mainly acidic side chains that were deprotonated and negatively charged at high pH. POE: *think net charge----> going to be basic or acidic amino acids---> protonation vs de-protonation depends on the pH!