Altius FL 1 Test Chem/Phys Review Flashcards
Q1
The key in the question is that they wanted an answer that will give the MOST EFFECTIVE OF all the options and would detect the PRESENCE and NOT ABSENCE of the deuterated products. It is important to note that deuterated products are similar to hydrogenated profucts except that the deuterium has an atomic weight that is higher than hydrogen which is a key in the passage for the answer. The correct answer will attend to that difference. Gas chromatography is wrong because it deals with boiling point differences in liquids with a mobile gas phase. UV spectroscopy is looking at conjugation differences which will be rooted in the electron and proton profile but these are equal in both cases. 1H NMR Spectroscopy could be answer because it will detect only the hydrogenated compounds and not the deuterated compound. Also, it is wrong because the question asks for one that will detect the presence but not the ABSENCE. Additionally, the clue in the 1st paragraph ending shows that the improved performance is as a result of the increased atomic weight.
Q2
Correct. It could not be charge because their atomic number is equal so A and C are out. It could not be D because due to their atomic number (proton, electrons, and lone pairs), they would still have the same molecular geometry. The answer had to be B.
Q3
Correct. It could not be A or B because both describe absorption, in which light energy is absorbed and the result is the excitation of electron to a higher energy level. It could not be C because emission is when light energy releases photon energy and NOT positron energy. The key to this answer is also in the 1st paragraph where the background and mechanical process of OLED is summarized.
Q4
Correct. The key to this question was recognizing that after looking at Pb in the question, what is the characteristic of higher zero-point energy between two atoms. The key is in the second paragraph where they say that heavier isotopes have a lower zero point energy. As such, the answer should be a lighter isotope that will have a higher zero-point energy. To answer this question, it is important to know what the criterion is to have a higher-zero-point energy. This can be achieved by keeping the atomic number constant and looking at the changing mass number.
Q5
Correct. The answer is a restatement of the Hendersen Hasselbach equation. It is important to note which particular ratio they are looking for. Is it Base to Acid or Acid to Base. This is a subtlety in the question. I got this because I paid attention that that discrepancy and noted it.
Q6
Correct. For me, it was a restatement of Le Chatelier’s principle. The stepwise thing in this question is asking (from the options): what is the effect of the breakdown of fatty acids (well it releases H+)? This leads to an increase in H+ concentration, hence a lower pH and acidic environment. Le Chatelier’s principle states that the body counteracts this to return to equilibrium by shifting to the left (in the case of equation 2) in order to decrease the production of H+ ions.
Q7:
I got this correctly but my clue was in the options. In the future, I need to know what exactly hyperventilation is, what is the effect of hyperventilation? Why does it occur? in addition, I also need to be aware of the definition of other related concepts like hypoventilation, etc. This is a content review question.
- Pearl divers in Japan are able to dive for long periods of time, without breathing, to harvest pearls. Is it reasonable to conclude that the blood pH of these divers would decrease near the end of a dive?
I got this correctly because I learnt how to eliminate answers from the options but in the future with a confusing option, I could have got it by paying attention to the question. The question gives a clue “without breathing”. That means that there will be little exchange of gases (oxygen and CO2) when they are underwater and throughout that journey. With that in mind, there will be a decrease in oxygen and an accumulation of CO2. Le Chatelier’ principle can be applied to note that there will be an equilibrium push to the right because of an accumulation of CO2 and thus leading to increased H+ and therefore acidosis.
- H3PO4, the molecule primarily responsible for the maintenance of pH in the cytosol, contains three acidic protons. Which equilibrium constant is associated with cytosolic buffering by H3PO4?
This I got wrong but the going forward, I need to review solubility, acids, bases, titrations, and more. The trick here is that you should know the three dissociation profiles of the acid in mind. After you are aware of that, you have to know which profile is dominant in which pH region based off of the graph. The key here in the question is that the answer is cytosolic (pH ~7). With that in mind, the answer will be in the profile that corresponds to this specific pH and that is why my answer was wrong and theirs was the correct one.
11.) Which change in solution composition would cause a protein to elute from a hydrophobic interaction column?
I got this correctly by making an educated guess. The answer here is recognizing what a hydrophobic interaction column is and how it achieves its process and then using this knowledge to answer the question. The logic of this question now is very interesting and I need to review all chromatography columns now. The proteins have various interactions but the reason why is adheres to the column is because all its interactions are being accounted for. The hydrophobic regions are staying put because their hydrophilic regions are also staying put. So to reduce it, you have to reduce the solution region, hence decrease the salt concentration. If the question had asked what change we want in the column, then the answer would be to increase salt concentration. A and B would be correct if in A, the column was acidic and we were making it basic or if the solution was basic and we were making it acidic. This logic can be used in determining answer B.
12.) Students added HCl dropwise to a solution of phospholipids with an initial pH of 7.4. Upon reaching a pH of 4.0, what changes will have occurred to the [COO-] and [COOH] present on the phospholipid head?
Wrong. The answer here was B and the logic in one case is to realize that acid form and basic form cannot increase simultaneously. One has to increase while the other decreases. Hence C and D are automatically wrong. When you think of acid solubility, acid dissociates and causes water to have a proton added to it. The water can now donate the proton and with this logic, it will donate it to the organic acid and thus lead to the protonated form. It is important to note that if the option had “decreased COO-“, it will still be wrong because that’s not the mechanism. the mechanism is because water has an increased concentration of H+ and the anion is pulling it and becoming protonated in the process.
When illuminated, the solar cell is analogous to a battery. In this context, which portion of the solar cell acts as the positive terminal?
The logic they want you to use here is to understand circuit flow elements. Electrons flow from the negative to the positive terminal and current flows from the positive to the negative terminal. And terminals are limited to electrods and nothing else. There is still a need to understand voltaic cells, electrolytic cells, and what batteries are considered.
14.) If the solar cell is illuminated by monochromatic light in the visible spectrum, which color would produce the most electrical energy per photon?
The question stem is asking you which will be the most efficient. The key to this answer is to recognize the graph shown in the passage which has to do with efficiency. Red and violet can be ruled out because based off the graph, they are at the extremes and as such they will be the least plausible answer. Ultraviolet is wrong because it asked for an answer in the visible spectrum but UV light is out of it. It had to be GREEN after elimination but most importantly after looking at the graph. RECOGNIZE definitions!
15.) The two parallel plate electrodes give the solar cell an inherent capacitance. If the distance between the plates in Figure 1 were increased from 20 µm to 40 µm, the capacitance would:
Formula for capacitance is the key.
16.) Figure 3 compares solar cell efficiency for light of various wavelengths. For four wavelengths, 400 nm, 525 nm, 700 nm, and 820 nm, which wavelength contains photons with the most energy?
There is a difference between most energy per photon and photons with the most energy.
- Knowledge of the formula is required E = hf or the other forms with wavelength
18.) If the in vitro GC analysis were conducted at a reduced temperature, how would the spectrum obtained differ from Figure 1?
- Effect of temperature on GC. Higher will make it quicker but will not affect the inherent polarity.
- Lower will make it slower and will increase peaks since some would not be overlooked.
19.) What do the mass spectral fragmentation data for the muconaldehyde isomers reveal about the relative stability of geometric isomers? Under electron impact ionization:
Mass spec science needs to be learnt. It tells you the fragment, its abundance, its stabilitiy based on the abundance and the atomic weight (mass/charge ratio).
- No information on the cleavage and boiling point.
21.) One theoretical model of enzyme-substrate interaction explains enzyme catalysis as a function of the stabilization of the transition state by the enzyme active site. This is an example of the:
- Distractors were catalysis and Michaelis-Menten mechanism.
- Lock and key as it implies but too much energy to release following function
- Induced fit makes up for this by stabilizing the transition state and able to dissociate following interaction.
23.)
What is the most likely result of a mutation in chymotrypsin from Asp-102 to Glu-102?
- Mutations are detrimental most times, hence there has to be some effect.
- It couldn’t be large because the inital stuff was the optimal and hence digression begins to decrease it.
- There has to be a change. Do not confuse for SILENT MUTATION! This is not the case.
- For the science and concept, see how a larger size can affect the active site or a smaller size. Go down to the basic level.
26.) The magnetic field in an MRI machine is created by a current in a solenoidal (spiral-shaped) wire. The magnetic field in a solenoid is given by the equation below, where n is the number of turns per unit length, I is current, and µ0 is a constant. If the strength of the field at the center of the solenoid is known, what additional information is needed to determine the current carried in the wire?
- Constant typically will not affect the solution of something. the unknown is more critical
- Use the formula to answer.
30.) The slope of a Hill plot is used to quantify enzyme cooperativity. Given the graph below, what is the Hill coefficient for GCK?
- Hill plot mechanism
- Hill coefficient = slope
- Slope > 1 (rise over run) positive is cooperative
31) Which biomolecule is most likely to compete with glucose for binding at the GCK active site?
- Recognize that enzyme is involved so it is competing with somethign that can enter its active site.
- Think of a similar shape and structure.
- Learn structure of Acetyl-coA, linoleic acid, sucrose
- Sucrose could have been the answer if mannose was not there because it is the same size and just an epimer but sucrose has two sugars joined.
32.) For an enzyme such as GCK, which exhibits positive cooperativity, each successive ligand will:
- What are positive, negative, and no cooperativity?
- Graphs
- What do they mean according to the enzyme and the graphs?
- Positive cooperativity, relates to association and dissociation, is that when you bind of one thing, the binding to the other subunit will be faster and stronger than the previous one.
- Negative cooperativity, relates to association and dissociation, is when you bind to one thing, the binding to the other subunit is slower.
- No cooperativity is when binding is simultaneous in all sites and at once (I think)
33.) Which conclusion about normal GCK allostery is most consistent with the data in the passage?
- Use both the stated data and the figure plus statistics to answer the question.
- A, C, and D are contradicted in both the passage and the data or figure.
- C is based off the proposed theory of number 2 and which it follows.
