Chem/Phys II Flashcards
(208 cards)
1
Q
What is homotropic regulation?
A
When a molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzyme’s activity (O2 = homotropic allosteric modulator of hemoglobin)
2
Q
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
The volume of a mass of air is not constant
3
Q
With decreasing temperature:
A
Air is able to hold less H2O
4
Q
The complete conversion of three moles of glucose by aerobic fermentation yields how many moles of acetic acid?
A
6
5
Q
Which of the following phase changes are exothermic processes?
A
Liquid to solid and gas to solid
6
Q
What is spectrophotometric absorbance?
A
Used to measure the concentration of metal ion remaining in aqueous solution following extraction (materials absorb light of a certain wavelength)
7
Q
How does adding electron-withdrawing functional groups increase acidity?
A
They provide inductive stabilization of the conjugate base by pulling electron density away from the negatively-charged position
8
Q
What is the Henderson-Hasselbalch equation?
A
pH = pKa + log [B] / [A]
9
Q
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
10
Q
What is the principal quantum number?
A
The first quantum number (n), denotes the energy level of the electron, higher principal quantum numbers = greater energy, farther from the nucleus (relates to row of the periodic table)
11
Q
What is the azimunthal quantum number?
A
Letter (l), denotes the subshell in which the electron is found, values range from 0 to n-1 (0 = s subshell, 1 = p subshell, 2 = d subshell, 3 = f subshell)
12
Q
What is the magnetic quantum number?
A
Letter (ml), denotes the spatial orientation of the electron, values = -l to l
13
Q
What is the spin quantum number?
A
Letter (ms), denotes the spin orientation of the electron, which relates to its angular momentum (m = +/- 1/2)
14
Q
The high-energy radiation produced by the gamma rays has sufficient energy to:
A
Generate free radicals, excite electrons to higher energy levels, and eject electrons from molecular orbitals
15
Q
Free radicals from ionizing radiation are highly unstable and have carcinogenic effects. These effects most likely result from damage to:
A
Nucleic acids
16
Q
When electrons move from the excited to ground state:
A
There is a loss of vibrational energy
17
Q
If a scientist chooses not to employ a SEC column, but wishes to fractionate a protein sample on the basis of only molecular weight, what technique would be most appropriate?
A
SDS-PAGE
18
Q
What is another name for tert-butyl chloride?
A
2-chloro-2-methylpropane
19
Q
Atrial fibrillation is the most common heart arrhythmia, causing palpitations, fainting and chest pain. According to the information in the passage, what is most likely to be observed in the ECG during atrial fibrillation?
A
Missing P waves and an irregular rate
20
Q
What regions of an ECG are most likely to be explained by the movement of sodium ions into a cardiac neuron?
A
P, Q, and R
21
Q
What is the formula for phosphorous acid?
A
H3PO3
22
Q
Efforts to treat lactic acid buildup in muscles were attempted using dissected muscle specimens in the laboratory. One of these experiments involved ammonium formation from dissolved ammonia. Under conditions of excessive lactic acid:
A
The final concentration of ammonium will be higher than otherwise due to lower pH (ammonia will convert to its conjugate acid, ammonium)
23
Q
How is Solubility Enhancement Ratio calculated?
A
By dividing the solubility of A in a certain media by its solubility in water
24
Q
What of the following boundaries would give the lowest-quality image to a physician?
A
Muscle/bone
25
The piezoelectric effect, when generating ultrasound waves, involves the conversion of:
Electrical energy to mechanical energy (the piezoelectric effect begins with voltage generating a current through the crystal (electrical energy) and culminates in the crystal vibrating (mechanical energy))
26
Conversion of pyruvate into glucose requires enzymes present in:
Both the mitochondria and the cytosol
27
What is the chemical formula for alkanes, alkenes, and alkynes?
CnH2n+2, CnH2n, and CnH2n-2
28
What is the Arrhenius equation?
k = Ae^-Ea/RT
29
What is the net charge on a valine molecule in the human body?
0
30
What is an example of an amphiprotic molecule?
Sodium bicarbonate, NaHCO3
31
What are the units of the Boltzmann constant?
J/K
32
What is true about solvents for TLC?
Anhydrous methanol has a greater eluting strength (adheres to the stationary phase) than pentane when used as solvents in a TLC procedure
33
An ideal buffer should have:
A pKa within 1 pH unit of the expected experimental conditions
34
What is normality?
The number of moles of protons per liter of solution
35
What is associated with higher antioxidant actiivity/thermodynamic favorability?
Lower enthalpy values
36
What is vitamin B1?
Thiamine, a coenzyme in metabolic processes including amino acids and carbohydrates (deficiency = Korsakoff's syndrome -> memory derangement/language problems)
37
What is vitamin D?
A lipid-soluble molecule primarily involved in calcium metabolism
38
What is vitamin K?
A group of closely-related molecules that contribute to blood coagulation and clotting
39
In comparison to the cohesive forces between water molecules of the protein solution droplet, how can the strength of interaction between water and oil molecules at an oil-water interface be characterized?
Weaker, because they are forces created by induced polarity in nonpolar molecules
40
What is a spherical lens?
It can be converging or diverging, and it may not cause the light rays to converge any sooner
41
Light inside the thin glass tube of a laproscopic surgical device strikes the edge of the glass tube and is entirely reflected back into the tube, with none of the light exiting to the surrounding medium. Which of the following must be true?
Incident angle is greater than or equal to the critical angle
42
Which of the following acids is expected to generate the strongest hydrogen bonding?
HF
43
A researcher carries out a column chromatography at physiological pH, using a stationary medium with a net positive charge. If a solution containing the following oligopeptides is poured into the column, which oligopeptide will most likely be found in the first fraction collected?
Positively charged will elute first (won't stick to stationary phase, elute the fastest with the mobile phase)
44
If a given channel in a nerve membrane shows a preference for transporting larger solutes, which of the following would increase the likelihood of a given particle being transported by the channel?
Adding an electron to a Cl atom to create a Cl- ion
45
Oligodendrocytes:
Serve to increase nerve conduction velocity in the central nervous system
46
What is the purpose of the long tail on Coenzyme Q10?
To allow CoQ10 to stay in and move in the hydrophobic portion of the inner mitochondrial membrane
47
Oxidation of aldehydes produces which functional group?
Carboxylic acids
48
What would result if CoQ accepted only one electron instead of two?
There would be a free radical
49
Which of the following characteristic changes in the IR spectrum would indicate the conversion of a fatty acid to an ester?
Disappearance of a broad peak in the 2500-3300 cm^-1 region only (loss of an OH group)
50
What is amperes equal to?
Coulombs per second
51
What equations can I use together?
V = IR and I = Q/delta T
52
Why are synthesized trans fats used as substitutes for saturated fats?
The hydrocarbon tails of trans fats stack more densely than those of comparable cis fats, making them less likely to be liquids at room temperature
53
Hematoporphyrin usually forms a complex with:
Fe2+
54
When NADH is oxidized, what happens to the hybridization of the nitrogen on the nicotinamide ring, and the C4 carbon atom opposite the nitrogen?
Both and nitrogen and the C4 carbon are converted from sp3 to sp2 hybridization
55
Even though enols are good nucleophiles, what are even better nucleophiles?
Their conjugate base, enolates
56
What is the process of a Claisen condensation?
An ester enolate reacting with another part of an ester
57
Surfactant-substrate interactions can involve which of the following intermolecular forces?
London dispersion forces, hydrogen bonding, and ion-dipole interactions
58
Anion surfactants most likely reduce the rate of nucleophilic reactions of hydroxide ion with neutral compounds by:
Forming a negatively-charged surfactant-substrate complex that repels the nucleophile
59
When does beta positive decay occur?
When the proton-to-neutron ratio is too high
60
The surface temperature of the sun (5770 K) is much greater than that of the earth (298 K). As a result, solar photons have a much higher energy than Earth photons. Given that information, how does the frequency and velocity of an Earth photon differ from that of a solar photon?
The frequency of the Earth photon would be lower; the speed of the photons would be identical
61
What is a chaotropic agent?
Any molecule in aqueous solution that can disrupt the hydrogen bonding network including the bonds between water molecules
62
What does a high SASA (solvent-accessible surface area)?
It indicates the residue is located at the surface of the protein, and therefore is less likely to be critical for overall protein structure
63
Which of the following gases would decrease the pH when dissolved in an aqueous solution?
Carbon dioxide
64
Individuals with a large bone cross-section:
Are more likely to experience a fraction
65
Refractive myopia is corrected by the use of a diverging lens of appropriate optical power. When compared to a healthy eye, a myopic, but otherwise normal, eye’s near point is most likely:
Smaller than that of a healthy eye
66
What is an example of a stereoselective reagant?
Diethyl tartrate (stereospecific = SN2)
67
An object floats in water with 4/5 of its volume submerged. If the object is then placed in a type of oil with a density half that of water, which of the following is true about the object placed in the oil?
The object will sink to the bottom
68
p-p-nitrophenol has a pKa of 7.16, whereas ethanol has a pKa of 16. What best explains this difference?
Anion stability achieved by delocalized pi electrons across the phenolic salt
69
What is a molecule?
A group or cluster of two of more atoms held together by chemical bonds
70
What is a compound?
Two or more different types of elements combined chemically in a fixed proportion
71
What makes something a good nucleophile?
Electron density, negative charge, the conjugate base is always a better nucleophile, less electronegative
72
In polar aprotic solvents:
nucleophilicity increases going up the periodic table
73
In polar protic solvents:
nucleophilicity increases going down the periodic table
74
What is the difference between spring force and spring work?
F = -kx, W = kx/2
75
Remember!
AN OX and RED CAT
76
If a question is asking about how much charge is transferred:
It is probably good to write out a balanced equation
77
Remember:
Current and electrons always flow in opposite directions
78
At pH = 7.3, what is the bond order of the shortest bond to oxygen in glycine?
1.5 (at physiological pH, the carboxyl group is deprotonated, the negative charge is delocalized by resonance between the two oxygen atoms)
79
More energy is needed to evaporate water to vapor than to melt ice to water because:
No hydrogen bonds exist in water vapor
80
When looking at solubility:
Look at polarity
81
The rate-limiting step has:
The highest Ea
82
Short-chain saturated fatty acids present in some animal products can produce a rancid odor if they are released from a triglyceride. Which of the following methods would prevent this type of rancidity?
Dehydration and sterilization (saturated = no double bonds, hydrogenation won't do anything)
83
Equation relating sound speed to wavelength and frequency
C = lambda * f
84
In classic Doppler ultrasound:
Readings become less accurate as cos theta approaches zero
85
What is the prime example of transverse waves?
Electromagnetic waves, including visible light
86
What would be a type of tissue used by Doppler ultrasound imaging?
Lymphatic tissue
87
To separate enantiomers:
Use a stationary phase with associated chiral substances (fractional distillation would not work for enantiomers)
88
In size-exclusion chromatography:
Smaller molecules get stuck in the pore system, while larger molecules pass right through
89
Equation relating electric field to membrane potential (voltage) and distance:
E = v/d
90
Why would critical protein residues be more likely to be conserved than non-critical residues?
Mutations to critical residues tend to produce a loss of function
91
What is thin-layer chromatography used for?
To separate non-volatile mixtures, compounds that have different polarities
92
What is recrystallization used for?
To make sure impurities are not within the final lattice structure; by slow cooling, the lattice forms slowly, and impurities are not trapped within the lattice structure
93
To separate enantiomers:
Use chiral resolution
94
When looking at chromatography:
The compounds will follow the STATIONARY PHASE
95
Which of the following is (are) present in a mixture of NH3 and BF3?
Bronsted-Lowry base (it is not a BL acid because there are no protons to donate)
96
Because hydrogenation usually decreses the oxidation number of hte atom the H becomes attached to:
It is generally considered reduction (ex. NAD+ -> NADH)
97
Halogens are often:
Leaving groups in nucleophilic substitution reactions
98
The transmembrane region of a protein:
Spans the lipid bilayer, largely hydrophobic (nonpolar)
99
Turbulent flow in humans is a major risk factor for atherosclerosis, the buildup of plaque on arterial endothelium. Ignoring any potential effects of turbulence, what effect would atherosclerosis have on blood flow?
Narrowing of the artery causes the velocity to increase and the hydrostatic pressure to decrease (would not change osmotic pressure because composition of blood would not change)
100
A carbohydrate:
Only contain carbon, hydrogen, and oxygen, not phosphorus
101
A steroid:
Is a hormone derived from cholesterol, would not characteristic ring structures
102
A peptide:
Is a relatively small polymer of amino acids
103
During an experiment involving the effect of roller coaster riding on neck muscles, all participants reported a feeling of weightlessness in the loop segment of the roller coaster ride. At which of the following positions did this feeling occur?
At the top of the loop
104
What is the equation for the decibel level of sound?
dB = 10log (I/Io)
105
Which of the following enzymes is LEAST likely to be synthesized in the outer mucosal layer of the colon?
Fructokinase
106
A way to identify sucrose among sugars is to use the Benedict’s test for reducing sugars. As the first carbon of glucose and the second of fructose are locked together in the sucrose molecule, no carbon is easily oxidized, and the Benedict’s test is negative. Starch contains a great deal of glucose but gives a negative Benedict’s test because:
Each starch molecule has only one free aldehyde carbon available for oxidation, and the resultant reaction is too slight to be observed
107
Gases generally have greater solubility:
As the partial pressure of the gas increases, and in cooler liquids
108
In which of the following aqueous carbohydrate solutions would a given vesicle have the greatest buoyancy?
Buoyancy = displacement of fluid when an object is submerged, depends on density of solution
109
If the average bone mineral density is 3.88 g/cm3, which of the following is a reasonable estimation of the density of the average human body?
1 g/cm^3
110
A physician hypothesizes that the PA effect could be generated by modulating the intensity of radiation delivered by a continuous light source, rather than by illumination with pulsed light. Is this physician correct?
Yes, because the magnitude of thermal expansion and contraction will vary with the intensity of incident radiation
111
Sound waves reaching the ultrasonic transducer propagate through brain tissue via which of the following mechanisms?
Collision of adjacent particles within the tissue
112
What are sphingolipids?
Glycosylceramide lipids containing a sphingosine backbone, an 18-carbon amino alcohol, bound to a fatty acid head group through an N-acyl linkage (25% of lipids in myelin sheath)
113
What is sphingomyelin?
A complex phosopholipid formed by the ester linkage of ceramide to a molecule of phosphocholine or phosphoethanolamine (derived from sphingolipids)
114
During the synthesis of bile, cholesterol is conjugated by the addition of a carboxylic acid residue. Bile salts are thus able to solubilize lipids in aqueous digestive secretions because bile salts:
Have a polar region and a nonpolar region, thus increasing the water-solubility of lipids
115
What is true about IR spectra of alcohols?
The infrared spectra of most alcohols are typically recorded as neat liquid films or Nujol mulls
116
Where are singly bonded C-O stretches typically found in IR?
1100-1000 cm^-1
117
In the fluorometry methods described in the research, the wavelength of emitted radiation depends on:
The wavelength of excitatory radiation and the electronic structure of the molecule being analyzed (produces wavelength and intensity of emission spectrum)
118
Would it be possible for the researchers to use gas chromatography (GC) for the isolation of retinol during SRA?
Yes, provided retinol vaporized without degradation
119
Is hexane polar or nonpolar?
Very nonpolar
120
Absorption of radiation corresponding to what portion of the electromagnetic spectrum is most likely to excite Aequorea fluorophore, a green fluorescent protein used in biological experiments?
Green flourescence = low energy/frequency, needs to be excited by a high frequency radiation = ultraviolet light
121
In order to image target blood vessels, researchers must first determine the index of refraction of skull bone. What is the minimum information required to make this determination?
The velocity of light in the sample (equation: n = c/v)
122
More double bonds/more of a conjugated system would result in:
A more stable structure
123
If entropy increases:
Disorder increases (order decreases)
124
Which of the following must be true for a biochemical reaction at equilibrium?
Delta G = 0
125
The structures of glycine and asparagine are displayed below. What type of interactions would be increased for a protein if glycine is mutated to asparagine?
Hydrogen bonding
126
The only amino acid that forms covalent bonds with other side chains are:
Cysteine
127
Copper (II) ions in aqueous solutions cannot be directly extracted into organic solvents without an extractant because the ions:
Have greater solubility in water than organic solvents unless complexed with extractant
128
Hydrogen bonding between molecules will be present when:
The molecules contain an O, N, or F atom covalently bonded to an H atom
129
Dipole-dipole interactions occur between:
Only polar molecules
130
London dispersion forces only occur between:
Nonpolar molecules
131
What are induced dipole interactions?
An electrostatic force (the attractive force between positively-charged and negatively-charged atoms)
132
The blood-brain barrier prevents molecules from easily entering the central nervous system unless they are able to pass through the lipophilic plasma membranes of the cells making up the barrier. Which of the following is most likely to be true?
Diethyl phthalate is more likely to cross the blood-brain barrier than phthalic acid because it lacks hydrogen-bonding hydroxyl groups
133
Many hydrotopes, like sodium benzoate, are synthesized by the reaction of a weak acid with a strong base. This is similar to the synthesis of:
Soaps (surfactants)
134
A chiral molecule in solution is found to rotate light in the clockwise direction. This species successfully undergoes a unimolecular nucleophilic substitution reaction. The product solution will rotate plane-polarized light:
Not at all (SN1 reaction = 2 products, racemic mixture -> no net light polarization)
135
A particular biomolecule is known to have 30 diastereomers and does not exist in any meso forms. How many chiral centers must this molecule have?
2^n = 32 -> n = 5
136
Isooctane and n-octane are best described as:
Structural isomers
137
What is the different between anomers and epimers?
Both similarities differ at one place, but for anomers they would only differ at the anomeric carbon
138
For two carbohydrates to be considered anomers, what must be true?
They need to have different stereochemistry solely at the anomeric carbon, which is the atom that serves as the carbonyl carbon in the molecule’s straight-chain form
139
What are Grignard reactions used for?
To alkylate compounds that contain carbonyl functionalities
140
How does branching affect boiling point?
Increases surface area available for intermolecular attractions -> ability for molecules to attract each other -> lower BP
141
How would halogenating n-heptane change the boiling point?
Produce a polar bond between the halogen atom and one carbon, allow the product to experience dipole-dipole forces, raising the BP
142
Which isomeric form of 2-chloro-3-bromobutane is most thermodynamically stable?
Alkanes do not have cis and trans isomers
143
In organic chemistry, radicals are extremely reactive species that possess at least one unpaired valence electron. Radical reactions, such as free-radical halogenation, can be instigated in a number of ways. Potential radical initiators include:
UV light and di-tert-butyl peroxide
144
What is an example of an alkyl halide under SN1 conditions that would form the most stable carbocation?
2-bromo-2-methylpentane (tertiary alkyl halide)
145
Between cis-2-pentene and trans-2-pentene, which one would have the higher melting point?
Trans = lower boiling; higher melting
146
Ethene is exposed to H2 in a solution containing a chunk of solid palladium. If it reacts successfully, the original alkene will:
Be reduced to form ethane (hydrogenation = a form of reduced)
147
If you wish to promote an E1 reaction, you should use:
A tertiary substrate, a mild base, heat, and a polar protic solvent
148
What is UV-Vis spectroscopy mainly used for?
Conjugated system
149
To increase the pKa, or make the proton less acidic:
We are looking for an electron-donating group, like tert-butyl
150
To donate hydrogens:
A molecule must contain a hydrogen atom that is covalently bound to either oxygen, nitrogen or fluorine
151
Consider the course of a typical SN1 reaction. The intermediate generated by the rate-limiting step is best described as:
An unstable intermediate with vacant orbitals
152
Tert-butanol is a common laboratory reagent that spontaneously degrades in solution to yield 2-methylpropene. To prevent this reaction and prolong the shelf life of tert-butanol, which of the following measures would be effective?
Adding a small amount of pyridine to the storage vessel, and storing the tert-butanol in a cold place
153
A chemist fills two separate beakers, one with 70% ethanol and the other with 70% ethanethiol. If subject to standard conditions, both beakers will have a pH of:
Less than 7, with ethanethiol having the lower pH of the two
154
4-tert-butylcyclohexanol can be classified as:
A secondary alcohol (OH = next to carbon attached to 2 alkyl groups)
155
Between ethoxide, ethanol, tert-butoxide, and tert-butanol, the strongest base is:
Tert-butoxide (tert-butanol = very weak acid, negative charge on tert-butoxide is fully concentrated on the lone oxygen atom)
156
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?
Hydrogen bonding
157
What type of functional group is formed when aspartic acid reacts with another amino acid to form a peptide bond?
An amide group
158
In gas-liquid chromatography:
The molecule with the lowest molecular weight/weakest intermolecular forces will be the first peak
159
If the amount of H+ in a solution is increased:
The perecentage of ionization would decrease
160
The energy of electromagnetic radiation is directly proportional to:
The number of photons -> intensity = energy emitted/time
161
Work is equal to:
Power x time
162
What reaction is catalyzed by lipase A?
Hydrolysis of triacylglycerides
163
If there is an amino acid subsitution like R33G:
The wild-type amino acid (R) changes to a variant amino acid (G)
164
UDP contains uridine, which is a nucleis acid used in:
RNA
165
In beta-minus decay:
An electron is emitted, so a neutron in the molecule is converted into a proton
166
Branching occurs:
Through an a-1,6-glycosidic bond in glycogen
167
If a molecule has a high negative charge:
The dissociation of it will occur to the least extent
168
Which of the following most likely will occur if a homogeneous catalyst CANNOT be separated from the products at the end of a reaction?
The products will be contaminated
169
A reaction is spontaneous if:
E is positive
170
What are four ways to define power?
J/s, ft*lb/s, W, kg*m^2/s^3
171
What are some true statements about aldehydes and ketones?
Acetals cannot form under basic conditions, and hemiacetals and hemiketals exist in equilibrium with aldehydes and ketones
172
What is an alpha hydrogen?
A hydrogen that is bound to the carbon immediately adjacent to a carbonyl carbon (very acidic)
173
Reaction of 4-methyl-1-pentanol with chromic acid should produce:
4-methylpentanoic acid
174
Since the kinetic enolate is favored by low temperatures, it also is:
Less stable
175
Compared to its analogous acyl chloride, a carboxylic acid is considered:
Less electrophilic due to resonance
176
What is the compound with the best and worst leaving group?
Acid anhydride = best; ester = worst (very unstable)
177
What is the stability of acid anhydrides and esters?
Acid anhydrides are less stable/more reactive than esters
178
What is transesterification?
The conversion of one ester to another via reaction with an alcohol
179
If you wished to convert octanoic acid into a significantly more reactive molecule, you would most likely:
Expose it to SOCl2
180
Why is acetyl iodide a better leaving group than acetyl fluoride?
I -> bigger molecule -> better able to delocalize negative charge
181
The reaction between propanal and cyanide forms a:
Cyanohydrin (cyanohydrin reaction = aldehyde or ketone with a cyanide anion or nitrile)
182
Many hydrolysis reactions form:
Carboxylic acids
183
An amide is to a lactam as an ester is to a:
Lactone
184
A student is attempting to isolate several products from the organic layer of an extraction. Initially, her solution contains an alkene, a phenol, a secondary alcohol, and a tertiary alcohol. If she begins the separation process by adding a moderately strong base, which substance is most likely to move into the water layer?
The phenol (during extractions, substances move into the water layer when they become charged/deprotonate the strongest acid)
185
How are polar and nonpolar solvents used for monosubstitution/polysubstitution?
Nonpolar = monosubstitution; polar = polysubstitution
186
What is the halogenation of a phenol?
Reacting p-chlorophenol with chlorine in carbon disulfide (nonpolar solvent = monohalogenation)
187
Out of lactose, sucrose, maltose, and starch, which one has a beta-acetal linkage?
Glucose (beta-1,4 linkage)
188
What would cause a positive Benedict's test?
Containing a free aldehyde
189
Why are ketals resistant to nucleophilic attack under basic neutral conditions?
Alkoxide ions constitute relatively poor leaving groups
190
What is the difference between IR spectroscopy and UV-Vis spectroscopy?
IR = absorption of incident light directly into chemical bonds, UV-Vis = electronic excitation from the HOMO to the LUMO
191
What is the difference between NMR spectroscopy and mass spectroscopy?
NMR = determining the content and purity of a sample as well as its molecular structure; mass = measures mass-to-charge ratio, is shown by mass spectrum (a plot of intensity as a function of the mass-to-charge ratio)
192
Why is SDS a useful reagant for gel electrophoresis?
SDS confers a uniform charge density to all proteins in the sample, and it is amphipathic, allowing it to denature most globular proteins
193
Compared to UV-Vis spectroscopy, IR spectroscopy is:
Reliant on the use of lower-energy radiation (UV-Vis = good for conjugated systems)
194
What direction would electric field lines go for a neuron?
Positive to negative charge (+ extracellulaar fluid to - axon interior)
195
What is the concentration of Cl- ions in a 0.1 M solution of calcium chloride?
Calcium chloride = CaCl2 = [Cl-] = 0.20 M
196
What makes something a reducing sugar?
Contains a hemiacetal group, undergoes mutarotation, and will be oxidized by Ag+
197
What charge do the C terminus and N terminus contribute to the charge of the peptide?
C-terminus = -1, N-terminus = +1
198
If the level of aqueous solution was higher inside the buret than outside, the pressure of the gas inside the buret would be:
Lower (Pressure outside = higher)
199
An ultrasound examination could show the motion of a fetus. In order to image this motion, the ultrasound examination devices requires what minimal information?
The speed of the sound, and the frequencies of the sound waves emitted and observed
200
What is the relationship between boiling point and vapor pressure?
Higher boiling point = lower vapor pressure
201
What is the difference between the principal and azimunthal quantum number?
Principal = radial size of an electron cloud, azimunthal = shape of an electron cloud
202
What does a fatty acid consist of?
A hydrocarbon tail and a carboxylic acid
203
If neither reactant is chiral, a chiral product can still form because:
The catalyst (the enzyme) is chiral
204
What is nearsightedness also called?
Myopia (diverging lens)
205
What procedure can be used to remove the water from the frozen sample?
Sublimation under reduced pressure
206
What are two examples of amino acids that can carry a positive charge?
Histidine and Arginine
207
What does lactate dehydrogenase do?
Converts lactate to pyruvate and back, oxidizes NADH to NAD+
208
When choosing a buffer conducted at a certain pH, it would be best to choose one with a pKa of:
Within one value of pH
