First we have actually 1,4-benzenediol is likewise known as hydroquinone and has two hydroxyl groups attached come opposite end of the benzene ring at carbons C1 and also C4. Next, we have actually the simplest members the the quinone class. Benzoquinones, or you’ll ever before hear them described as just quinones. Perform you have to know this structures? Well, they’re found on AAMC’s contents outline, so you should have these down. Our DHB looks much closer to hydroquinone, for this reason I have a hunch our answer will certainly be regarded the hydroquionone structure more than the benzoquinone.

You are watching: Aamc section bank c/p 62

Carboxylation that hydroquinone During carboxylation, a carboxylic acid team is developed by treating a substrate v carbon dioxide. Ours DHB has actually two hydroxyl teams attached to opposite ends, but also a carboxyl group. This looks choose a an excellent choice for now.Oxidation of hydroquinone We do like answer selections with hydroquinone. But oxidation would be a ns of electrons by hydroquinone. That’s no what’s walk on here. The contradicts the picture from the passage.Reduction of benzoquinone We view benzoquinone as our choice here and that contradicts our malfunction of the question.Hydroxylation of benzoquinone This answer an option is interesting. Hydroxylation would present the vital hydroxyl teams to the central ring, the same way we watch in hydroquinone. But our DHB has two hydroxyl groups and the carboxyl group. Exactly answer is answer choice A, the carboxylation that hydroquinone.

3) during MALDI-MS, we have separation of ions that take trip to the multiple sclerosis detector in the uniform electrical field region. We’re asked specifically around the experimental feature that reasons this. We’ll have to go back to our passage to revisit some specifics around the separation the the ions. However at that is core, what is this inquiry asking united state to do? recognize the relationship in between variables.

Here we view our diagram through the ion traveling towards the multiple sclerosis detector. The passage states “the velocity the the ion is inversely proportional to their mass-to-charge ratio.” So that would typical a high mass-to-charge ratio coincides to a slow velocity. A short mass-to-charge ratio coincides to a biggest velocity. We likewise know every ions take trip a street of 0.5 m to the detector, so we’ll likely have actually to describe the velocity distinction along the way.

Distance took trip by ions relies on the ion charge. We nothing think this is the case. All ions take trip 0.5 meters. Street is fixed, yet we compare selection A through our other answer choices.Velocity the ions counts on the ion mass-to-charge ratio. We said a high mass-to-charge ratio coincides to a slow velocity. A short mass-to-charge ratio synchronizes to a higher velocity. The velocity difference might explain the separation of the ions. We’ll keep choice B because that now.Time of travel is inversely proportional to the ion mass-to-charge ratio. This is the contrary of ours breakdown. Slower molecules take more time since they have greater mass-to-charge ratio. Time of take trip is directly proportional to the ion mass-to-charge ratio. Also when us don’t have specific numbers or quantitative values, we’re still having actually to save track the the relationship in between variables.Electric field between the MALDI plate and also the ms analyzer is uniform. electric field, similar to distance traveled, is walk to be the exact same for all ions. It’s not helping to different the ions. Exactly answer is answer choice B.

4) We’ve doubled frequency and also we’re given four hypothetical lasers in ours answer choices. We have actually to discover the answer choice with statistics the are an ideal for the MALDI technique. We’ll need to go back to our i to look in ~ our table the summarized attributes of the radiation. Just like you did in the previous question, the relationship between our variables. Frequency multiply by wavelength is a constant. So once one variable doubles the various other is cut in half. If frequency is doubled, wavelength is halved and vice versa. Power is not pertained to our frequency or wavelength.

So below we have our table and again, this are suitable characteristics, so our potential answer have to be related to one of these 2 sets that values. Our power is conserved, therefore it’s going to be 1.5 milliwatts or 2.2 milliwatts. We’ll also pay attention to the matching wavelengths together well. Our concern stem states we require to find a laser an ideal for MALDI method after frequency is doubled. So, when we look at our answer choices, we’re looking for a wavelength that once halved corresponds to among our values in our table. 

Laser A: wavelength 826 nm, strength 1.2 mW. If we dual frequency and half 826 nanometers, we gain 413 nanometers, and also power that 1.2 milliwatts. 413 nanometers walk not enhance the wavelength in Table 1, and also power the 1.2 milliwatts is not among our options. Laser B: wavelength 714 nm, strength 1.2 mW. If we twin frequency and half 714 nanometers, we obtain 357 nanometers, and power that 1.2 milliwatts. Again, 357 nanometers go not match the wavelength in Table 1, and also that is not a viable strength value.Laser C: wavelength 650 nm, strength 1.5 mW. If we dual frequency and fifty percent 650 nanometers, we get 325 nanometers, and power that 1.5 milliwatts. 325 nanometers matches Table 1. So far so good. Yet 325 nm likewise corresponds to power of 2.2 milliwatts, not 1.5 milliwatts. This answer selection is far better than A and B, but still not totally there.Laser D: wavelength 532 nm, strength 1.5 mW. If we twin frequency and fifty percent 532 nanometers, we get 266 nanometers, and also a power of 1.5 mW. This check out with the table, and also our breakdown of the question. What to be the key in finding this answer? The relationship in between our variables.

5) come answer this question, we’re going come look at Table 1 and also see which of our answer selections corresponds to among the values of electromagnetic energy delivered during a pulse. We’re walk to be referencing the passage, we’ll be converting part units most likely, and also converting between values based upon some equations and relationships that are general knowledge. If necessary, we have the right to round our number or adjust them to scientific notation, so keep in mind our answer options go to one decimal place and also units room microjoules. 

We have Table 1 here. We’re going to it is in doing part unit conversions to do sure whatever is in the proper units and also we’re comment the right question. Remember, our last unit is in microjoules, and we’re searching for a final answer that goes one ar past the decimal point.

We have wavelength. Then power is characterized as work/time. Occupational input is energy, so when we isolate for energy, power = strength * time. 

So, we two feasible energy worths then:Energy1 = 1.5 mW * pulse expression of 5 multiple sclerosis = 7.5 microjoulesEnergy2 = 2.2 mW * pulse expression of 2 ms = 4.4 microjoules.

2.0 µJ This to be the size of one of the pulses in milliseconds, but not ours predicted value. Fine still store A come compare.3.5 µJ If we divide the pulse term of 5 milliseconds by power of 1.5 milliwatts instead of multiplying, we obtain a value close come 3.5 microjoules, yet we understand that is no the correct way to fix for power here.7.5 µJ we multiplied 1.5 milliwatts through a pulse term of 5 millisecond to obtain 7.5 microjoules. This matches among our two predictions, for this reason we have the right to eliminate selections A and also B.8.0 µJ which again does not enhance our predictions. What we perform want come pay fist to, is the various other answer options are similar to other values we have in the passage, yet the systems don’t always match up. What this means for you, is you can sometimes obtain by by just focusing on dimensional analysis, and lining increase units. The MCAT doesn’t test super high-level physics, and like ns mentioned, each calculation is often only a couple of steps. If you obtain stuck and also have exhausted every one of your knowledge and ideas, girlfriend still desire to make certain you match up units and the corresponding numbers. This is a last resort. We constantly want our units to complement up still, but we still carry out our calculations come make sure we have actually our ideal number values.

6) to answer this question, we’ll have to think ago to the passage and how the sample is prepared, and also we’ll most likely use outside information to actually describe the reaction. 

The passage mentioned, ‘Proteins can be “fingerprinted” using MALDI if they space subjected come proteolytic cleavage prior to analysis.’ So, our emphasis here is walking to it is in on proteolytic cleavage. Proteolytic cleavage is the hydrolysis that the peptide bonds in between amino acids in proteins. This procedure is commonly done through peptidases, which space enzymes. Enzymes are provided in both content classification 1A and also Content classification 5E, and various other subtopics, therefore they’re critical on the MCAT!

Oxidation. These space reactions bring about the addition of oxygen and also removal the hydrogen. We claimed proteolytic cleavage entails hydrolysis which contradicts this answer, yet we still keep choice A come compare.Reduction. Reduction results in the enhancement of hydrogen and also removal that oxygen. This is the opposite of answer selection A, however still contradicts our hydrolysis answer choice. We still keep options A and B.Hydrolysis. This matches our breakdown. The i mentions we’re examining peptidases, and proteolytic cleavage entails hydrolysis.Isomerization. Our molecule is undergoing proteolytic cleavage, it’s no just transforming the plan of atoms. This price is unreasonable, so us stick with our answer choice C, hydrolysis.

Section Bank: Chemical and also Physical foundations of organic Systems: i 2

7) It can be tempting to shot and pick solution based on differences we know around these methods coming right into the exam. However it clearly says “based top top the passage.” We’re going to failure what us know about calorimetry, and also then to compare to the setup offered in the passage.

Calorimetry supplies the energy released from every little thing happens inside a room to warmth water bordering the chamber. The readjust in temperature the the water is measured come determine exactly how much energy must have actually been exit from the chamber. The takes part time to heat the water uniformly. The dissipation the the warmth throughout the whole volume the the water renders it so that the exact location of the warm transfer can’t be traced. An interpretation we’re unable to detect localized warm transfer.

The passage says “excess power is soaked up by the solution, leading to a neighborhood temperature increase. This fast and localized heater process…” the phrase must jump the end to us. Fast and also localized heating process creates a sound tide that have the right to be recorded. Traditional calorimetry was anything yet fast and localized, but PAC is.

can be provided on samples with certain heats bigger than water’s. neither the passage, nor the question stem talk around the specific heat of water. We don’t recognize which an approach can be offered on which details heats. Let’s keep going through our answers and also comparing.enables the measurement of fast and localized heat transfer processes. This matches our breakdown exactly. We touched ~ above the steps connected with both experiments, and also the PAC an approach allowed for fast and also localized warmth transfer processes. We can keep answer choice B and also eliminate answer selection based upon the second law the thermodynamics. second law that thermodynamics is about entropy and also this inquiry doesn’t really problem itself with entropy. The entropy that a system, consisting of the whole universe, is constantly boosting as long as nothing is hindering the increase. We can eliminate this price choice, it’s out of beneficial on samples in the solid phase only. I mentioned breaking binding of solute molecule in the breakdown. We can get rid of this prize choice. We’re left v our correct answer choice, answer selection B.

8) That means we’re using a certain laser to dissociate a particular chemical bond, and we want to know the energy meter reading. We can answer this concern using content, yet a quick glance in ~ our answer choices shows that the answer can be in terms of the details variables discussed in the passage. 

The passage say excess power after the laser hits the sample is soaked up and temperature increases. However in this case, we’re using an ideal laser, for a particular chemistry bond. 

Everything works in a details way, and the energy meter doesn’t choose up anything. That would only pick up if power was come come off, and then friend would recognize that there is an unforeseen variable in your measurements.

Looking at the diagram, you can see that the simple flow of energy goes indigenous laser (photon energy) –> come the lens (releases heat, resulting in sound waves) –> microphone –> and is picked up through the power meter.

When the laser/photon power is just right for a certain chemical bond, no excess warm is exit from bond breakages inside the cell, and also no sound waves are produced. The energy meter will review 0.


Glancing in ~ our answer choices, answer selection D matches our breakdown exactly. Answer selection B is the difference between the laser pulse energy, answer choice A, and also the warmth detected, answer choice C. Power is conserved, together we’re utilizing an ideal laser. We’re going to eliminate answer choices A v C.

9) We’re going come go back to the i to uncover our 3 compounds. We’ll use our basic knowledge to determine the framework of all 3, and we’ll pick response based ~ above similarities.

The i mentions phenols, thiophenols and also alkylbenzes. We can list lock all the end here. 

Phenols: hydroxyl team bonded to an fragrant hydrocarbon group.


Thiophenols: similar to phenols, but sulfur-containing


Alkylbenzenes: Derivatives the benzene, in i beg your pardon one or much more hydrogen atoms are changed by alkyl groups. Shown is toluene, the easiest alkylbenzene


Phenols, thiophenols, and alkylbenzenes every have aromatic rings.

Aromatic ring that matches our prediction.Alkyl this are present in alkylbenzenes, however not all 3 compounds, so eliminate answer an option BCarboxylic acid This wasn’t existing in any of ours predicted figures.Carbonyl Again, not current in any kind of of our drawn-out structures. Us can eliminate answer selections B-D and we’re left through our correct answer, answer an option A-aromatic ring.

10) In various other words, what function is walk to enable laser A to be perfect to cleave the details bond mentioned? stop go ago to the passage to discover Table 1 and the associated values.

We see our three species of bond here and the type of laser connected with each. We’re concentrated on laser A and also C. Enthalpy is higher for the -OH bond. Laser A is greater energy than laser C.

We can compare energy with frequency and also wavelength.

Energy of a photon is proportional come frequency:

E=hf . H is Planck’s constant.

We also know c = λf, which method that wavelength and frequency room inversely proportional So, ↑ power = ↑ frequency and also ↓ wavelength and ↓ energy = ↓ frequency and also ↑ wavelength.

Prediction is higher energy, higher frequency, and much shorter wavelength because that laser A.

be much better focused laser type C. This isn’t relevant to ours question, or describe the difference in between the laser. Let’s store comparing.have a higher frequency than laser type C. This matches our prediction. We claimed laser A has higher energy, higher frequency, and shorter wavelength. Keep answer selection B, us can remove answer an option A.have a much longer wavelength 보다 laser kind C. it is the the contrary of what we said. Laser A will have actually a much shorter wavelength. We can remove answer choice C.emit under photons every unit time than laser form C. This would suggest less power in laser kind A. That contradicts ours prediction so we can get rid of answer an option D. We’re left with our exactly answer, answer choice B. 

11) We can go back to the passage to reference number 1, yet we’ll usage the thin-lens formula to uncover focal length. Keep in mind the devices in our answer selections are in centimeters.

We have actually our diagram here. Let’s create out our slim lens formula:


Object street is 12 cm, image distance is 4 cm

1/12 + ¼ = 1/focal length

1/3 = 1/focal length

Focal size = 3 cm

This is a math problem where us did no round off or approximation. We have the right to look because that our exact, calculated worth of 3 centimeters. Our prediction matches answer selection A (3 cm) and we can remove answer options B-D. 

12) We’re going come go earlier to the passage to find details, especially the occupational function. We’re provided two values in the concern stem, frequency and h. We can solve this concern using the passage and the equation for kinetic power of photoelectrons.


We have part of the i up above, we have actually the values for f and also h below. 

The kinetic energy of ejected electrons (photoelectrons) is offered by KE = hf – work function, wherein hf is the photon energy, 

The i tells us the energy meter, based on the photoelectric effect, provides a detector with a work duty of 3.4 eV

Multiply h and also f. The seconds units cancel. The index number on the 10s space opposites, for this reason those cancel as well. We simply multiply 5.0 x 4.1 to acquire 20.5 electron Volts. Plug in numbers to solve for kinetic energy. 

KE=20.5 eV-3.4 3V = 17.1 eV

This was a math trouble where us did no round off or approximation. We deserve to look for our exact, calculated value of 17.1 electron volts; ours prediction matches answer choice C.

Section Bank: Chemical and also Physical foundations of biological Systems: questions 13-17

13) Let’s think about what we’re looking at in this question. We have actually a nucleophilic substitution, and also the rate determining action is unimolecular. Or in other words, one SN1 reaction. We’re provided 4 various alcohols, and told we have acidic conditions. Ultimately, i m sorry alcohol will certainly most most likely undergo substitution by an SN1 mechanism? 

A tertiary carbon or a second carbon is walking to it is in favored through SN1, vice versa, a methyl carbon or a primary carbon goes to SN2. In this case, because that SN1, we’re trying to find a tertiary or a secondary carbon that would get assaulted by the nucleophile. 

For SN2, mental the backside attack, and for SN1, mental the carbocation intermediate. In the SN1 reaction, the huge barrier is carbocation stability. The very first step that the SN1 reaction is ns of a leaving team to provide a carbocation, the price of the reaction will be proportional come the security of the carbocation. Carbocation stability boosts with enhancing substitution the the carbon (tertiary > secondary >> primary). 

We have actually acidic conditions, an interpretation protonation and production that water



Answer selection A is a major alcohol. We stated we’re in search of a tertiary or an additional carbon therefore we can have the many stable carbocation. Let’s save this answer choice for now and compare with our other options



 Answer an option B is a second alcohol. This matches our prediction. This carbocation is going come be more stable than the primary alcohol in answer choice A.



Answer choice C is a major alcohol. This is the opposite of what we wanted. We said major alcohols are our worst option here. We’re still keeping answer selection B is our finest option so far.



Answer an option D is a tertiary alcohol. This is the ideal answer an option we were looking for. The tertiary carbon is going to produce the many stable carbocation, for this reason it’s going to most likely undergo substitution and produce a water molecule. We can remove answer an option B, we’re left through our finest answer choice, answer selection D.

14) Let’s rest this down a little bit in ~ a time. We have a reaction between an amine and excess carboxylic acid anhydride. One of the products is walking to be an amide, and also we need to pick an extraction procedure that allows us to isolate this amide. 

First point we want to do is come lay out the reaction happening. We have an amine and also excess carboxylic acid anhydride that yields an amide and carboxylic acid. We had excess carboxylic acid anhydride, definition all of our amine would be converted, and also we’ll still have actually carboxylic mountain anhydride that didn’t react to amine. We address the anhydride first by dealing with it with a solid base or a solid acid. That’s going to transform the anhydride come an unreactive form. So currently we’ll have our amide, and also two carboxylic acids. We need to separate the amide native the carboxylic acid. We’re making use of an exploit procedure, so we need to separate the two compounds. We have the right to use charge and solubility difference. The method we can separate by fee is come deprotonate the carboxylic acid. How can we execute that? A solid base. The solid base can deprotonate the carboxylic acid, if amide is unaffected because of its high pKa. Therefore we deserve to separate our fee carboxylate and uncharged amide using an essential solvent. The amide have the right to then it is in filtered out.

Add 0.1 M NaOH(aq) to quench unreacted anhydride. Then add diethyl ether and separate the layers. The amide deserve to be obtained from the ether class by evaporating the solvent. This is regular with our malfunction of the question. Strong base will quench the unreacted anhydride. Meaning it’s now unreactive. The solid base deprotonates the anhydride and also we have actually a charge difference. We include diethyl ester, i m sorry is analogous to our organic solvent. The fee difference permits us to dissolve the amide, but the carboxylate i will not ~ dissolved. So, evaporating the solvent off the amide and leaving just the carboxylateAdd 0.1 M HCl(aq) to quench unreacted anhydride. Then include diethyl ether and separate the layers. The amide can be obtained from the ether layer by evaporating the solvent. The an initial part the the procedure is consistent with our process. However using a solid acid instead of a strong base doesn’t permit for the deprotonation of the anhydride and also give us that charge difference. We deserve to still preserve that A is our best option. Add 0.1 M NaOH(aq) come quench unreacted anhydride. Then include diethyl ether and separate the layers. The amide can be derived from the aqueous layer by neutralizing through HCl(aq). ours amide is in the organic layer and also we have to filter that to gain our amide. This contradicts what I stated in the break down of the question.Add 0.1 M HCl(aq) come quench unreacted anhydride. Then include diethyl ether and also separate the layers. The amide deserve to be acquired from the aqueous great by neutralizing v NaOH(aq). This is comparable to answer an option C, yet also, we’re utilizing a solid acid instead of a solid base. This contradicts our breakdown as well. We’re left through our correct answer, answer an option A.

15) Voltage is constant, so we must relate resistance and current. We’ll perform that making use of Ohm’s Law. Ohm’s legislation states the the existing through a conductor between two clues is straight proportional come the voltage throughout the two points. We can write the end Ohm’s regulation as:

V=IR. Voltage equals present times resistance. Voltage is continuous in this question. Minimum resistance will certainly be when current is in ~ a best (since they are inversely proportional). The existing is greatest at about 7 come 8ms. Worth of the existing is approximately 400 x 10^-12 Amps follow to the graph. We can plug in the worths we’re provided to solve for minimum resistance.

V=IRVoltage=Current x resistance

Solving because that resistance:R=V/I

R=80 mV/(400 x 10^-12 A) = 200 MΩThis to be a math trouble that didn’t involve much rounding. Instead, we addressed for the minimum resistance together 200 MΩ. We deserve to compare all 4 of our answer options at once. Our correct answer is walking to it is in answer choice C.

16) We have a graph mirroring the relationship between frequency and also intensity. We’re concentrating on the y-axis and also want to recognize the ratio between the maximum and minimum sound intensities. Looking at the chart, the max strongness level is 80 dB. The minimum soot level is 30 dB. Decibels space logarithmic. Definition every 10-dB rise is much more powerful by a 10 multiplier. So, a 20-dB increase is rise by 10^2. A 30-dB increase is much more powerful through 10^3. 50-dB boost is an ext powerful by 105. 

This is a relatively straightforward question that just associated reading the graph offered to us. We solved for an accurate value, so we can compare every one of our answer selections at the exact same time. We’re going to pick the answer choice that’s the same as our prediction, the proportion is 105.

17) We’re utilizing the photo in the concern stem and also external expertise to answer this question. We’re going to know about Ohm’s law, currents, and also resistors in series. An initial thing we want to suggest out, is as soon as the voltmeter reads zero, the voltage DIFFERENCE in between those points is zero. For this reason that means they are at the very same voltage. 

Let’s look in ~ our resistors: R1 and also R2 space in series. R3 and also R room in a series. Then R1 and also R2 are in parallel v R and also R3. Existing through R1 and also R2 is equal, and also the present through R3 and R is equal. We have a present through R1 and R2 (I) and a present through R and R3 (I’).

Ohm’s legislation is V=IR. We understand that the voltage is the very same for the segment include R1 and also the segment comprise R; us can set up the relationship:V= I*R1 and also that is also equal come I’*R

as well together the relationship:V= I*R2 and that is same to I’*R3 together the voltage should be exact same in these sections as well.

Now, if we execute some math and also isolate R in the first equation, we gain I/I’ * R1= R. But nothing in our answer selections contains current. So, we need to uncover a way to remove current.

If we deal with from ns from the 2nd equation, we acquire I = I’*R3/R2.

Now, we plug the quantity of I right into the equation isolated because that R, and also see that I’ cancels out, and we are left with:(R3*R1)/R2=R


We addressed for the precise relationship. We stated R equals R3*R1/R2. We can pick our correct answer, answer selection D.

Section Bank: Chemical and also Physical structures of biological Systems: i 3

18) come answer this question, we’re walk to recommendation the figure from the passage, however then we’ll use our basic knowledge to in reality classify the lipid molecule.

Compound 1 is a phosphatidylcholine. Phosphatidylcholines save on computer both phosphorus and also choline head (nitrogen part), and also are found in cabinet membranes. Compound 1 is going come be offered to synthesize liposomes. How have the right to we attach this framework to liposomes? Liposomes space spherical vesicles and they mimic cell membranes (phospholipid bilayer). Keep these vital points that our structure handy, and also go earlier to our answer choices. 

Triacylglycerols. Triacylglycerols have actually three fatty acids attached to glycerol. No choline head.Pyrophosphates. Pyrophosphates have two phosphates in Phosphorus-oxygen-phosphorus linkage. Not the situation here-we have our phosphorus and also choline head, yet it’s not a pyrophosphate.Phosphatides. This is continual with our prediction. Phosphatides save both phosphorus and also choline head (nitrogen part). This is currently the finest answer choice.Phosphonic acids. This consist that a single pentavalent phosphorus covalently bound via single bonds to a solitary hydrogen and also two hydroxy groups and also via a dual bond to an oxygen. Ours phosphorus below is double bonded to an oxygen, however we don’t have actually the 2 hydroxyl teams here. Answer selection C remains our ideal option. 

19) come answer this question, we’re going to referral the experiment in the passage, however then we’ll usage our basic knowledge to define the nature of liposomes and how size-exclusion color layer analyzer work.


In size-exclusion chromatography, molecules space separated based on their size. Separation is achieved through differential exclusion where the biggest molecules elute the fastest, when the smallest molecules elute the slowest.

Liposomes have actually a spherical structure while enables them to be supplied as a vehicle to carry drugs and also nutrients. The experiment entails synthesizing liposomes v a reaction in between Compound 1 and also in the visibility of dye. As the liposomes room formed, they will certainly be filled v the dye-containing solution. Size exemption chromatography is supplies to different things. Together the liposomes room filtered v size-exclusion chromatography, the liposome will certainly break up and also release the dye, an interpretation the solution fluoresces.

The macromolecule had extensive conjugation. once you look at the molecule over there is no conjugation. Our large indicator for conjugation is alternating twin bonds. This is an unreasonable answer choiceFluorescent dye to be trapped inside. This matches our break down of the question. The liposomes rest up and also release the dye that was trapped inside. This answer choice is superior to answer an option A.Intermolecular interactions reduced the power of the excited state. decreasing an energy state would certainly release a color, no fluorescence. And also if this to be the situation the experimenters wouldn’t need to have to deal with dye and also fluorescence in the an initial place. Also, keep in mind the a color would only be released if a covalent/ionic shortcut happens. In this case, the liposomes are producing a bilayer that is organized together by valve der Waals forces, which doesn’t yes, really decrease the energy state. There’s no color, and that’s additionally why they necessary fluorescent dye.Light reflects from the surface of the sphere. This isn’t exactly how light works, and the fluorescence is indigenous the dye being physically exit from the liposome. We’re left through our correct answer choice, answer an option B fluorescent dye to be trapped inside.

20) In the passage we uncovered there were differences when we combined the compounds. Link 1 was secure to mixing, however Compound 2 formed brand-new liposomes. We desire to understand why precisely this distinction existed. That method we’re walk to reference the experiment in the passage, but then we’ll usage our basic knowledge to describe the behavior differences. Rapid glance in ~ our answer selections shows we’ll have to distinguish in between kinetic and also thermodynamic control. 

The passage claims “Liposomes developed from link 1 were steady to mixing, but mixing those from link 2 formed new liposomes v an mean size expected for the efficient final lipid concentration.” compound 1 no change; link 2 easily results in the formation of brand-new liposomes. 

We have to distinguish in between kinetic control and also thermodynamic control, therefore let’s perform some quick background. Short reaction times favor kinetic control, whereas longer reaction times favor thermodynamic reaction control.

Example: product A forms much faster than product B because the activation energy for product A is reduced than that for product B, but product B is more stable. In together a case A is the kinetic product and is favored under kinetic control and B is the thermodynamic product and is favored under thermodynamic control. The pathway that’s favored counts on the problem of the reaction. 

If a reaction is under kinetic control, it is stated that the desired product/major output product the the reaction is the one that is formed most quickly and also has the shortest activation energy barrier. The usually associated with irreversible reactions. It explains why Compound 1, after creating the liposomes, doesn’t type more energetically steady liposomes top top mixing.

Thermodynamic control, is choice for a an ext stable product (lower complimentary energy). No matter which product forms first, if there is a lower power state product that can be formed, then it will certainly be formed. This is linked with reversibility. That explains why link 2 is able to reverse the liposome developing reaction, and kind more energetically stable liposomes after ~ mixing. Our answer is kinetic regulate for link 1 and thermodynamic control for compound 2.

both compound 1 and Compound 2 room under kinetic control. Remember, we said just compound 1 is under kinetic control. Link 2 is under thermodynamic control. This contradicts our breakdown.Compound 1 space under kinetic control, yet those all set from link 2 space under thermodynamic control. This price is saying exactly what I stated in our breakdown of the question. Compound 1 space under thermodynamic control, however those prepared from link 2 room under kinetic control. This answer an option is the contrary of ours breakdown, therefore answer selection B stays the finest option. both compound 1 and also Compound 2 room under thermodynamic control. only Compound 2 is under thermodynamic control, no Compound 1. Compound 1 is under kinetic control. We can stick v our correct answer choice, answer choice B.

21) We’re shown the over table that gives us diameter vs elution volume. Diameter goes indigenous 50 nanometers come 200 nanometers in the table. We desire to recognize the lipid concentration necessary to prepare liposomes with a diameter of 250 nm. We deserve to solve this concern by making use of information offered in the passage. Our score is come relate the visual in the concern stem through the one native the passage.

The graph in the inquiry stem shows us an inverse partnership with diameter and also elution volume. Together diameter increases, elution volume decreases. With this information, we can predict the a diameter of 250 nanometers will certainly correspond to an elution volume of less than 10mL. 

Now, look at number 1 on the right- we have another inverse relationship here. Together elution volume boosts along the X axis, we have a to decrease in concentration.

Let’s combine this information: 250 nanometers method we have a larger diameter, a smaller elution volume. That way an rise in concentration. The concentration must be bigger 보다 0.20mM since that elutes at ~10mL. So that’s our expected answer: better than 0.2 millimolar.

Quick glance in ~ our price choices and we can actually compare every one of them in ~ once. The concentrations are all in the very same units and go from the the smallest concentration to largest concentration from options A to D. The only answer selection greater 보다 0.2 millimolar is answer selection D: 0.30 millimolar.

22) We deserve to solve this concern by utilizing information given in the passage. We’ll use number 1 in the passage, and we’ll be making use of data analysis.

For liposomes that elute in ~ 20 mL, the equipment concentration is 0.1 mM. The solution offered to synthesize liposomes to be 1 mL of differing concentrations, therefore we deserve to solve because that numbers of moles using volume and also molarity. 

We have the right to use dimensional analysis. Let’s write out our calculations come make certain units and prefixes space in order.

We have molarity (0.1 x 10^-3 mol/L) X our aspect (1 mL x 1 L/1000mL) = 0.1 x 10^-6 moles

0.1x 10^-6 mole x (800 g/mol) = 8 x 10^-5 grams OR 80 micrograms (μg)

80 µg matches our prediction exactly8 mg 8 milligrams is equal to 8 x 10^-3 grams. Not correct value80 mg 80 milligrams is same to 8 x 10^-2 grams. Untrue value.8 g is another incorrect value, for this reason our exactly answer an option is answer selection A, 80 micrograms.

23) We have the right to solve this question by utilizing information provided in the passage, specifically figure 1. Compound 2 is able to reverse the liposome forming reaction, and kind more energetically stable liposomes ~ mixing. We’ll analyze our figure with this in mind. 

Mixing equal quantities of the 0.10 mM and also 0.2mM will yield a suspension same to a concentration the 0.15mM. 

The an unified concentration the 0.15mM, has an elution volume of about 16 or 17 mL. So that 16mL is the only place we would check out the fluorescence bump. 

And simply for compare purposes: separation, personal, instance elution volumes for 0.10 mM and also 0.2mM space at around 20 mL and ~12 mL 


Answer an option A has two bump at roughly 12 ml and also 20 ml. We simply said these are individual elution quantities for 0.1 millimolar and 0.2 millimolar concentration. 

Answer choice B has the same two bump at 12 mL and also 20 mL. We’re getting the very same bumps as answer an option A, for this reason there’s a possibility we end up eliminating answer choice along through answer A for saying the exact same thing.

Answer an option C has a solitary bump at around 25 mL. This would be the situation at a an extremely low concentration, no the roughly 0.15 millimolar concentration in this question.

Answer selection D has actually a solitary bump at about 16 mL, i m sorry is consistent with ours breakdown. We can pick our exactly answer, answer an option D, and also eliminate all our various other answer choices.

Section Bank: Chemical and also Physical structures of biological Systems: questions 24-28

24) We’re given the cost-free energy that the hydrolysis the ATP. We’re asked about the ratio of ADP come ATP at equilibrium given details conditions. Come answer this question, we’ll need to collection up the equilibrium constant expression and find exactly how it relates to the free energy that the reaction.

First point we have the right to do is discover the equilibrium consistent expression. 

For reactions involving a heavy or a liquid: the amounts of the heavy or liquid will readjust during a reaction. But their concentrations won’t change. Instead, the worths for solids and liquids remain constant. And also because lock constant, your values are not included in the equilibrium continuous expression. Water is a fluid so it’s not included. Let’s compose out our expression:

Keq = /

Now we deserve to relate our expression v the totally free energy the the reaction:∆G° = -RT ln K 

We can substitute K from above into this equation, so plug in given values: ∆G=-30 kJ/mol, RT= 2.5 kJ/mol, =1.0M. 

Note: In voluntary reactions, the authorize for ∆G will be negativeSolve for / which equates to e12This to be a math difficulty that no involve rounding. Instead, we resolved for the ratio of ADP to ATP at equilibrium. Our calculated worth is e12. We deserve to compare every 4 of ours answer options at once. Our correct answer is walk to be answer an option D.

25) We’ll have to use the regular table and also subsequently discover the electron construction of cobalt ion.

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Elemental cobalt is facet number 27, an interpretation it has 27 protons and 27 complete electrons typically. In this case, we’re taking care of cobalt ion. Cobalt loses 2 electrons to gain a +2 charge. Elemental cobalt has actually 9 valence electrons, yet cobalt cation has actually 7 valence electrons.

Elemental cobalt has actually an electron configuration 3d7 4s2

We have to be mindful with some transition metals. Because that cobalt, we need to recognize whether the 2 electron are shed from the 4S or the 3d orbital. In this case, once electrons are shed from Co atom, they are lost from the 4