Missed C/P Questions Flashcards
What was the principal factor determining the migration of individual components in the sample with paper chromatography?
Hydrogen bonding. The relative amount of hydrogen bonding to the stationary phase will determine the relative rate of migration of the various components in the sample.
What type of functional group is formed when aspartic acid reacts with another amino acid to form a peptide bond?
An amide group
What is the difference between an Amine and an Amide
The main difference between amine and amide is the presence of a carbonyl group in their structure; amines have no carbonyl groups attached to the nitrogen atom whereas amides have a carbonyl group attached to a nitrogen atom.
What type of reaction forms a peptide bond? What is the leaving group?
Condensation or dehydration synthesis. H2O is leaving group
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
The answer to this question is C because HCl is a strong acid that will increase the amount of H+ in solution and thus decrease the percentage of CH3CO2H that ionizes.
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.
The answer to this question is D because the 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 conversion from Hz to THz?
1 Hertz = 1x10^-12 THz
What is standard atmospheric pressure in mmHg, Torr, and atm?
760 mmHg, 760 Torr, 1 atm
What does lipase do?
Lipase is an enzyme that breaks down dietary fats into smaller molecules called fatty acids and glycerol.
Which type of bond is formed by glycogen synthase upon release of UDP?
A.α-1,4-Glycosidic bond
B.α-1,6-Glycosidic bond
C.β-1,4-Glycosidic bond
D.β-1,6-Glycosidic bond
The answer is A because the bond that is formed by glycogen synthase is the main chain linkage of glycogen, which is an α-1,4-glycosidic bond. UDP release means that only glucose was added.
What types of bonds occur with glycogen branching?
Branching occurs through an α-1,6-glycosidic bond in glycogen.
Each of the following equations shows the dissociation of an acid in water. Which of the reactions occurs to the LEAST extent?
A.HCl + H2O → H3O+ + Cl−
B.HPO42− + H2O → H3O+ + PO43−
C.H2SO4 + H2O → H3O+ + HSO4−
D.H3PO4 + H2O → H3O+ + H2PO4−
The answer to this question is B. HPO42− has a high negative charge and so dissociation of it will occur to the least extent.
Which of the following most likely will occur if a homogeneous catalyst CANNOT be separated from the products at the end of a reaction?
A.The catalyst will become heterogeneous.
B.The products will be contaminated.
C.The reaction will not occur.
D.The reaction rate will speed up.
The answer to this question is B. If a homogeneous catalyst cannot be separated from the products at the end of a reaction then the products will be contaminated with the catalyst. I
How will the rate of a catalyzed reaction be affected if the solid catalyst is finely ground before it is added to the reaction mixture?
A.The rate will be faster because a greater mass of catalyst will be present.
B.The rate will be faster because a greater surface area of catalyst will be exposed.
C.The rate will be slower because the fine catalyst particles will interfere with product formation.
D.The rate will remain the same because the mass of catalyst will be the same.
The answer to this question is B because grinding a heterogeneous catalyst increases the amount of catalyst available to the reaction and therefore increases its rate.
Which measurement unit CANNOT be used to express power?
A.kg•m2 •s2
B.J•s-1
C.ft•lb •s-1
D.W
The answer to this question is A because the measurement unit of power is watt, defined as J/s = ft•lb/s = kg•m2/s3.
What is the equation for dB?
1dB = 10 log10(I/I0)
where I0 is a reference intensity equal to the human threshold of hearing, 10–12 W/m2
The mathematical expression for h is:
A. mv2/2.
B. v2/(2g).
C. mg.
D. mv.
The correct answer is B.
Conservation of energy implies KEinitial = PEfinal, or mv2/2 = mgh; therefore, h = v2/2g. Thus, B is the best answer.
How do you find λ using frequency (f) ?
λ = vsound/f
What does the focal length of a mirror depend on?
The radius of the curvature
Visible light travels more slowly through an optically dense medium than through a vacuum. A possible explanation for this could be that the light:
A. is absorbed and re-emitted by the atomic structure of the optically dense medium.
B. is absorbed and re-emitted by the nucleus of the material in the optically dense medium.
C. bounces around randomly inside of the optically dense medium before emerging.
D. loses amplitude as it passes through the optically dense medium.
The correct answer is A.
A is known to occur and is the reason for the slowing down of light. B is incorrect because the nucleus is involved. C is incorrect because the motion of the photons is certainly not random. D is true but does not answer the question. Thus, A is the best answer.
Which circuit elements store energy?
Capacitors
Resistors
Batteries
Capacitors and Batteries
How do you find the pressure in a cylinder contain a liquid?
Pressure is given by (density) • g • (height)
What are the relationships between intensity and dB?
10x intensity = 10^1 = 10 dB
100x intensity = 10^2 = 20 dB
1000x intensity = 10^3 = 30 dB
This is because β = 10Log(I/I0)
A climber using bottled oxygen accidentally drops the oxygen bottle from an altitude of 4500 m. If the bottle fell straight down this entire distance, what is the velocity of the 3-kg bottle just prior to impact at sea level? (Note: ignore air resistance)
What equation would you use to solve this?
A is correct. As an object falls, the kinetic energy (KE) that it gains is equal to the potential energy (PE) that it loses. Thus, for this object, we can say that 1/2m(vfinal)2 = mgΔh, where g ~ 10 m/s2:
½(3) (vfinal)2 = 3(10) (4500)
(vfinal) 2 = (10)(4500)(2)
(vfinal) 2 = 9 x 104
vfinal = 3 x 102 m/s = 300 m/s
The hemoglobin (Hb) dissociation curve at high altitude has a distinct shape from that at atmospheric pressure. Which of the following best explains this shape?
D is correct.
The sigmoidal shape of the curve implies that as each oxygen molecule binds to Hb, the affinity of Hb for oxygen goes up. Homotropic regulation is when a molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzyme’s activity. O2 is a homotropic allosteric modulator of hemoglobin. The four subunits of hemoglobin actually bind to oxygen cooperatively, meaning the binding of oxygen to one of the four subunits will increase the likelihood that the remaining sites will bind with oxygen as well. This is the cause of the sigmoidal curve shown in the figure.
Homotropic regulation
Homotropic regulation is when a molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzyme’s activity. O2 is a homotropic allosteric modulator of hemoglobin.
Fluid pressure changes with depth are assumed to be linear. Which statement best explains why this does not hold true for atmospheric pressure changes?
A. At very high temperatures, air behaves less ideally. B. The volume of a mass of air is not constant. C. The majority of molecules in air are nonpolar. D. Air is not of a uniform composition.
B is correct. Hydrostatic pressure for liquids is linear because as depth changes, the density of the liquid remains constant. Gases, however, have densities that change according to the forces applied to them. Gases are compressible, while liquids and solids are not.
State what you know about the properties of gases
Gases lack a fixed shape and volume. The lack of a fixed volume—or compressibility—is especially important because it means that the density of a given gas is not constant. Rather, if the gas is forced into a smaller container, its density will increase as its particles pack more closely together
Melting/Fusion
Solid to liquid
Evaporation
Liquid to gas
Sublimation
Solid to gas
Condensation
Gas to liquid
Freezing
Liquid to solid
Deposition
Gas to solid
What are the endothermic phase changes?
melting, evaporation, and sublimation
What are the exothermic phase changes?
condensation, freezing, and deposition
What are the pKa’s of titration indicators?
Methyl orange 3.7 Bromophenol blue 4.0 Methyl red 5.1 Bromothymol blue 7.0 Phenol red 7.9 Phenolphthlein 9.3
What is the difference between a positive control group and a negative control group?
A positive control is a control group that is not exposed to the experimental treatment but that is exposed to some other treatment that is known to produce the expected effect.
A negative control group is a control group that is not exposed to the experimental treatment or to any other treatment that is expected to have an effect.
Cross Sectional Design Study
Cross-sectional studies investigate a population at a single point in time, looking for predictive relationships among variables. A limitation of cross-sectional designs is that they can show correlations, but not causation, because looking at changes over time is necessary to assess whether a cause-and-effect relationship is present.
Experimental design study
An experimental design involves manipulating a certain variable—known as an independent variable—to see what effects it has. The measured effects are known as dependent variables. Additional types of study design exist, especially in the social sciences; of note, qualitative research focuses on analyzing experiences rather than objective metrics.
How do you find % dissociation?
[H+]/[HA] x 100%
What is the Units of Power (P)?
1 Watt (W) Nm/s or J/s
What is the half life equation?
(1/2)^n
What is ADP to ATP?
ADP is OXIDIZED to ATP
When are the inductive effects the strongest?
Inductive effects increase if the electron-withdrawing groups are closer to the acid and if more of them are present
Suicide inhibition
also known as suicide inactivation or mechanism-based inhibition, is an irreversible form of enzyme inhibition that occurs when an enzyme binds a substrate analog and forms an irreversible complex with it through a covalent bond during the normal catalysis reaction.
How do you find mechanical advantage?
MA = hypotenuse / height OR MA = Fload/Feffort
A circuit is comprised of a 12-volt battery with three light bulbs with the same resistance. If two of the light bulbs are wired in parallel and are in series with the third light bulb, what happens when one of the parallel light bulbs is unscrewed?
A. All of the light bulbs remain lit. B. Two of the light bulbs remain lit. C. One of the light bulbs remains lit. D. All of the light bulbs go out.
B is correct. Even after unscrewing one of the parallel light bulbs, there is still a circuit for current to flow from the positive terminal to the negative terminal of the battery through the two remaining light bulbs
C, D: The current still has an available path to travel through the branch of the remaining parallel bulb and then through the series bulb. As such, these two remaining light bulbs will stay lit.
Air is bubbled through distilled water. The solution will have a pH:
A. greater than 7, because elemental nitrogen undergoes hydrolysis. B. less than 7, because elemental nitrogen undergoes hydrolysis. C. greater than 7, because carbon dioxide undergoes hydrolysis. D. less than 7, because carbon dioxide undergoes hydrolysis.
D is correct. Air contains elemental nitrogen as its major component, but elemental nitrogen is essentially inert and is neither an acid nor a base. On the other hand, carbon dioxide can undergo a hydrolysis reaction in liquid water to produce carbonic acid, a weak acid that produces a solution whose pH is less than the pH of water (pH = 7).
What is the Rf value in paper chromatography?
The Rf value is defined as the ratio of the distance moved by the solute (i.e. the dye or pigment under test) and the distance moved by the the solvent (known as the Solvent front) along the paper, where both distances are measured from the common Origin or Application Baseline, that is the point where the sample is initially spotted on the paper.
Which of the following molecules will have the highest Rf value when studied with thin-layer chromatography using a silica plate?
A. CH3CH2CH2CH2CH3 B. HOCH2CH2CH2CH3 C. HOCH2CH2CH2OH D. HOOCCH2CH2CH3
A is correct. Silica is a highly polar molecule; thus, when chromatography is done on a silica plate, a polar substance will move slower on the plate due to polar-polar interactions between the substance and the plate. This means that the Rf value of a polar substance will be smaller than that of a nonpolar substance since the substance will move less on the plate compared to the solvent front than a nonpolar substance would. Of the options given, the compound in answer choice A is the least polar.
When a patient is on the operating table for heart surgery, surgeons need to clamp major nearby blood vessels before cutting them because, according to Bernoulli’s equation, a volume of pressurized blood opened to the atmosphere:
A. will convert its pressure to kinetic energy, rapidly exiting the body and causing shock. B. will convert its pressure to potential energy, pooling at the high places of the body and causing a potential brain aneurysm or stroke. C. will match outside pressure by decreasing fluid speed, starving the body of oxygen. D. is at risk of over-oxidizing, dangerously increasing pressure.
A is correct. When the surgeons cut into the artery, blood will obviously shoot out of the body as a result of blood pressure. That pressure is converted to kinetic energy, causing the blood to move rapidly as it exits the body.
Ritonavir is an antiviral drug that mimics the natural substrate for a key viral protease enzyme. As a competitive inhibitor, ritonavir:
A. decreases the rate of reaction because it decreases the availability of ATP to catalyze the reaction. B. increases the rate of reaction by altering the tertiary structure of the enzyme. C. decreases the rate of reaction by binding to the enzyme and altering the structure of its active site. D. decreases the rate of reaction by binding to the active site.
D is correct. This question is asking us for the definition of a competitive inhibitor, which binds to the active site and blocks the substrate from attaching. The mechanism of a generic competitive inhibitor is depicted below.
A ray of light in air strikes the flat surface of a liquid, resulting in a reflected ray and a refracted ray. If the angle of reflection is known, what additional information is needed in order to determine the relative refractive index of the liquid compared to air?
A Angle of incidence
B Angle of refraction
C Refractive index of air
D Wavelength of the light
Solution: The correct answer is B.
To find the relative refractive index to air one needs both the incident and refracted angles. Since the angle of incidence is equal to the angle of reflection we will know the angle of reflection. We still must know the angle of refraction and this is answer B. None of the other answers will allow one to know the angle of refraction.
If the magnitude of a positive charge is tripled, what is the ratio of the original value of the electric field at a point to the new value of the electric field at that same point?
A 1:2
B 1:3
C 1:6
D 1:9
Solution: The correct answer is B.
The magnitude of the electric field E of a point charge is given by
E=kq/r^2
If q is tripled, E also will be tripled. Thus, B is the best answer.
Underproduction of pulmonary surfactant in IRDS leads to decreased compliance of alveolar tissue. Based upon this information, which of the following must be true regarding pulmonary surfactant?
A. Its adsorption to the water-alveolar interface increases surface tension, preventing alveolar collapse due to intra-thoracic pressure. B. Its absence decreases the minimum radial size of alveoli able to avoid collapse at a given pressure of inspired air. C. Its adsorption to the water-alveolar interface decreases surface tension, decreasing the pressure difference required to inflate the airway. D. Its presence increases the efficiency of gas exchange across the alveolar membrane by decreasing the surface area of the alveolus at a given pressure of inspired air.
C is correct. During inspiration, contraction of the diaphragm and external intercostal muscles leads to expansion of the thoracic cavity and a decrease in intrapleural pressure. This negative pressure, relative to atmospheric pressure at the entry of the upper airway, generates airflow through the respiratory tree and to its terminal extension—the alveoli. The elastic recoil force of the airway and the surface tension of the water lining the airway oppose expansion of the alveoli due to the influx of atmospheric pressure. Pulmonary surfactant adsorbs to the air-water-alveoli interface, reducing surface tension and the total force resisting expansion. This increases pulmonary compliance—a measure of lung volume change at a given pressure of inspired air—and decreases the work required to expand the lungs at a given atmospheric pressure. This is consistent with choice C.
In general, surfactant molecules are amphipathic, meaning that they contain both hydrophobic and hydrophilic regions. The diagram below shows surfactant molecules surrounding a micelle of oil. The hydrophobic tails of the surfactant molecules mix well with the hydrophobic oil, while the hydrophilic heads point away from the oil droplet.
the hydrophobic solute-solute interaction is spontaneous, and that ΔH and ΔG have opposite signs. Which of the following must be true for this interaction when temperature is a positive value?
I. ΔH > ΔG
II. 0 < ΔS
III. ΔH < ΔS
A. I only B. I and II only C. II and III only D. I, II, and III
B is correct. For the interaction to be spontaneous, the free energy change of the reaction must be negative. The question states that the enthalpy and free energy changes for the interaction have opposite signs. Thus, ΔG is negative and ΔH is positive, making Roman numeral I true. For a reaction to be both endothermic (positive ΔH) and spontaneous (negative ΔG), the reaction must involve an increase in entropy (ΔS is positive).
This is according to the equation: ΔG = ΔH - TΔS.
Thus, II is also true because ΔS is positive.
III: The quantity TΔS, not ΔS, must be greater than ΔH. For this reason, RN III does not have to be true.
Figure 1 shows a drop in the first ionization energy in going from beryllium to boron. Which of the following best explains the source of this drop?
A. Boron contains one valence electron, while beryllium contains none. B. After putting two electrons in the valence s-type subshell for beryllium, the third valence electron for boron must enter an orbital that already contains an electron of opposite spin. C. The two valence electrons for ground state beryllium are in an orbital with an azimuthal quantum number of l = 0, whereas the third valence electron in ground state boron must be in an orbital with an azimuthal quantum number of l = 1. D. The two valence electrons for ground state beryllium are in an orbital with a magnetic quantum number of m = +1, whereas the third valence electron in ground state boron must be in an orbital with a magnetic quantum number of m = -1.
C is correct. The electron configuration for beryllium is 1s22s2. The azimuthal quantum number for an s-type orbital is l = 0, which defines the shape of the electron cloud (a spherically-shaped electron wave, with no nodes). For boron, since the s-type orbital in the valence shell cannot hold more than two electrons, the third valence electron must be placed into a p-type orbital, giving an electron configuration of 1s22s22p1. The azimuthal quantum number for a p-type orbital is l = 1 (a dumbbell-shaped electron wave with one node at the nucleus). The 2p orbital is slightly higher in energy than the 2s orbital, making it slightly easier to ionize this electron. Choice C is the only answer option that correctly describes this situation.
The shapes of the s-type and p-type orbitals are shown below. (Note that multiple possible shapes exist for p-type orbitals.)
What is first ionization energy?
The first ionization energy is the energy required to remove one mole of the most loosely held electrons from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.
What molecules have higher first ionization energies?
Helium has the highest. All of the noble gases and halogens have high ionization energies. The period 2 elements also have high ionization energies.
Francium (FR) in the bottom left of the periodic table has the lowest
What does the quantum number (n) denote?
It denotes the energy level of the electron, and can take any integer value (≥1). Higher principal quantum numbers (for example, n = 2 rather than n = 1) have greater energy and are farther from the nucleus. The principal quantum number relates to the row of the periodic table in which the element in question is found.
What does the quantum number (l) denote?
The azimuthal, or angular momentum, quantum number (l) describes the subshell of the principal quantum number in which the electron is found, with values ranging from 0 to n − 1, where l = 0 is the s subshell, l = 1 is the p subshell, l = 2 is the d subshell, and l = 3 is the f subshell
What does the quantum number (ml) denote?
(ml) describes the spatial orientation of the orbital in question within its subshell. Potential values of ml range from −l to +l. Since each orbital can hold a maximum of two electrons, this means that an s subshell can contain up to two electrons, a p subshell can hold up to six electrons, a d subshell can contain up to 10, and an f subshell can hold up to 14.
What does the quantum number (ms) denote?
(ms) describes the spin orientation of the electron, which relates to its angular momentum. The two possible spin orientations are ms = −1⁄2 and ms = +1⁄2. Two electrons in the same orbital (and thus with the same ml value) are said to be paired and must have opposite spin.
Which of the following electronic transitions for a hydrogen atom would result in the emission of a photon that would be visible to the human eye?
A. n = 1 to n = 3 B. n = 2 to n = 4 C. n = 2 to n = 1 D. n = 4 to n = 2
D is correct. The visible spectrum contains electromagnetic signals with wavelengths ranging from 400 nm to 700 nm. The wavelength of light emitted during a particular electronic transition is determined by the energy difference (ΔE) between the final and initial energy levels. The energy of each level can be determined using Equation 1 and the principal quantum number in question. For light to be emitted at all, an electron must travel from a higher to a lower level, a process that releases energy. This automatically eliminates options A and B; however, we must actually perform calculations to choose between C and D.
The high-energy radiation produced by the γ rays has sufficient energy to:
I. generate free radicals.
II. excite electrons to higher energy levels.
III. eject electrons from molecular orbitals.
A. I only B. I and II only C. II and III only
The high-energy radiation produced by the γ rays has sufficient energy to:
I. generate free radicals.
II. excite electrons to higher energy levels.
III. eject electrons from molecular orbitals.
A. I only B. I and II only C. II and III only
