AAMC FL 2 C/P
Q: Based on the data presented in figures 2 and 3, what is the most likely role of Y229 in protein stability and cAMP activation?
A: A: Y229 is important for protein stability and cAMP activation -told in the passage it is not involved in cAMP activation -in figure 3, Y229A is shifted to the left -Y229A is the modified version of Y229 so we can say that from figure 2 the Y229A shifted tremendously (less stability) thus indicating that Y229 is important for protein stability
An inflatable cuff was used to temporarily stop blood flow in an upper arm artery. While releasing the pressure to deflate the cuff, a stethoscope was used to listen to blood flow in the forearm. The blood pressure reading was 130/85. Given this information, which of the following statements is LEAST likely to be true?
A: Blood flow was heard when the pressure of the cuff was greater than 130 mmHg. -Blood flow could not have been heard when pressure exceeded 130 mmHg. 130 mmHg is the systolic blood pressure, or the pressure measured when blood flow just begins to resume. my answer: Blood flow was heard when the pressure of the cuff was 90 mmHg. -this is true because diastolic is 85 here so it'd still be heard
Which single bond present in nitroglycerin is the LEAST polar? Choices: C-H C-O C-C O-N
A: C-C Bonds between identical atoms are likely to be the least polar
Which single bond present in nitroglycerin is most likely the shortest?
A: C-H sp shortest strongest bond biggest bond enthalpy
Q: When used in the place of spam, which peptide would be most likely to achieve the same experimental results?
A: FLGFEY told that original is FLGFTY -so the phosphorylated threonine has a negative charge and of all the answers FLFFAY FLGFQY -glutamine contains an amide (deadmidation) FLGFGY -glycine is achiral, most conformationally flexible FLGFEY, glutamic acid would most mimic the phosphorylated negative charge
Q: From the data presented in Figure 3, which Ria variant is most stable?
A: L203A -graph has temperature on the x axis -so the most stable one would required the most heat to denature
polar covalent bond
EN difference between 0.4 to 1.7 ex. C-O -electrons are shared unequally between atoms -melting points lower than ionic but greater than nonpolar -boiling points much lower than ionic compounds, but greater than non polar
ABSORPTION OF UV LIGHT BY ORGAN MOLECULES ALWAYS RESULTS IN WHAT PROCESS?
EXCITATION OF BOUND ELECTRONS
Keq > 1
Keq is much greater than 1, then the position of equilibrium is to the right; more products are present at equilibrium
[Cu(H2O)4]2+(aq) + 4NH3(aq)-> [Cu(NH3)4]2+(aq) + 4H2O(l) Would the concentration of [Cu(NH3)4]2+ increase if the equilibrium were disturbed by adding hydrochloric acid?
NH3 is much more likely to get protanated than H2O since it is a stronger base. Therefore the acid that you add is more likely to react with NH3 to form NH4+ than H20. This leads to a decrease in NH3, which means that according to le chatelier, that the reaction will shift to the left!
Charles' Law
V1/T1=V2/T2 It says that at a constant pressure, the temperature and the volume of a gas will be directly related
Stability of GC
actually have nothing to do with the hydrogen bonding difference and everything to do with base stacking. For some reason, the geometry of GC bonds stack on top of one another better, so the base stacking increases interactions between the pi orbitals which stabilizes the helical structure, thus increasing the temperature it dentaures at. -in summary: BASE STACKING FOR G-C STABILIZES HELICAL STRUCTURE and contributes to thermal stability
Q: which property is best used to estimate vapor pressure
apor pressure depends on the number of particles that can escape from the solution and into the gaseous phase. As a result, vapor pressure is directly proportional to temperature and inversely proportional to the strength of the intermolecular forces. When you increase the temperature, you increase the average kinetic energy of the molecules in the solution. This increases the number of particles in solution that can escape into the gaseous phase, thus increasing vapor pressure.
histidine is found
at active site
chymotrypsin cleaves
at the carboxyl end of phenylalanine, tryptophan, and tyrosine
Protein secondary structure is characterized by the pattern of hydrogen bonds between:
backbone amide protons and carbonyl oxygens. Secondary structures such as alpha helices and beta pleated sheets are local structures that are held together by hydrogen bonds between BACKBONES of adjacent amino acids. NOT SIDE CHAINS
coordinate covalent bonds
electrons are shared between atoms -both electrons are donated by one of the atoms -often have hybridized characteristics of both ionic and covalent bonds
ionic bonds
elements have electronegativity > 1.7 -far away from each other on periodic table -electrons are transferred from one atom to another -cation loses electrons is position -anions gain electrons and is negative -hgih melting point, high boiling point -liquid state conducts electricity -held in tight crystal lattice structure
covalent bonds
elements that have an electronegativity difference of < 1.7 -melting points lower than ionic -boiling points lower than ionic
peptide bond formation
form between amine and carboxylic acid group
Q: What is average power consumed by 64 year old woman during ascent of 15 cm high steps I her mass is 54kg?
given: -weight -hegiht so formula is P= W/t *where W= PE, PE=mgh SO told 30 steps so 30 x 0.15m gives you h then plug and chug
center of gravity or center of mass
if you apply a force to an object to the center of mass (for a Chad on Chad's Prep his stomach) IT WILL NOT ROTATE
when measuring blood pressure
inflate the cuff until you temporarily stop blood flow in the upper arm artery (you can hear this with your stethoscope). -The cuff will then deflate and the systolic pressure is measured as soon as you hear the trickle of blood start to flow again (turbulent flow). -The cuff continues to deflate as pressure decreases, and the diastolic pressure is measured when you can no longer hear the blood flowing because it is now laminar flow.
Which of the following atoms will have the smallest second ionization energy
ionization energy trend: increases going up and to the right
when formation constant Kf >>1
it is spontaneous process
IR
molecular vibrations
Qsp=Ksp
saturated -if you add salt you will get precipitate
bond order
single bond: longest, weakest, sigma bond, sp3 double bond: medium length, 1 sigma 1 pi, sp2 triple bond: shortest, strongest, 1 sigma 2 pi
sp3
sp3: single bonds - 1 SIGMA, 0 pi - tetrahedral -109.5 *if it has 1LP trigonal pyramidal *if it has 2LP bent
three fatty acids ester linked to a single sphingosine
sphingolipid
two fatty acids ester linked to a single sphingosine plus a charged head group
spingophospholipid
the stronger the intermolecular forces
the harder it is for molecules in solution to escape into the gaseous phase, thus producing a lower vapor pressure
the half-life of a radioactive material is
the time it takes for half of all the radioactive nuclei to decay into their daughter nuclei -it is not HALF the time it takes for all the radioactive nuclei to decay into their daughter nuclei
if the electrode temperature is high
then the favorability of the reaction will decrease
Qsp<Ksp
unsaturated -if we throw in some salt more will dissolve *Ksp solubility product *Qsp ion product
sp2
1 SIGMA, 1 PI bond -double bond -trigonal planar -120 *if it has 1LP: bent *if it has 2LP: linear
sp
1 SIGMA, 2 PI BONDS -triple bond -linear -180 *regardless of LP it is still linear
resistors in parallel
1/R=1/R₁+1/R₂+1/R₃+... V=V₁=V₂=...
non polar covalent bond
EN difference <0.4 SUPER CLOSE TO EACHOTHER ON periodic table ex. P-H -electrons are shared equalled between atoms ex. diatomic (N2, O2, Cl2) alkanes -melting and boiling point lower than polar compounds
Which statement correctly describes the structure of the DNA double helix?
A: The amount of guanine will equal the amount of cytosine in a DNA sequence. other choices: Nitrogenous bases pair with other bases in the same purine or pyrimidine groups. -purines and pyrimidines do not form base pairs with other members within the same group -Purines and pyrimidines are base pairs. The two most common base pairs are A-T and C-G. These nucleotides are complementary —their shape allows them to bond together with hydrogen bonds. In the C-G pair, the purine (guanine) has three binding sites, and so does the pyrimidine (cytosine) Sugar-phosphate backbones form the interior of the double helix. -sugar-phosphate backbones form the exterior of the double helix.
Q: the lone pair of electrons in ammonia allows the molecule to:
A: act as a Lewis base in water -Lewis Base donates an electron pair in forming covalent bonds. NH3 in water is allowed to act as a lewisbase. Water can act as an acid or base. NH3 is more basic so it will act as a base other choices: assume a planar structure -with the lone pair NH3 is trigonal pyramidal act as an oxidizing agent -NO if it donates its lone pair of electrons it becomes oxidized (reducing agent) OIL RIG act as a Lewis acid in water: accept electrons -since it has a lone pair it is likely to DONATE them now accept
Q: Based on the relative energy of the absorbed electromagnetic radiation, which absorber, a peptide bond or an aromatic side chain, exhibits an electronic excited state that is closer in energy to the ground state?
A: an aromatic side chain; the absorbed photon energy is lower told: aromatic (250-290nm) peptide: 190-250nm E= hf so the longer the wavelength the lower the frequency
Which of the following energy conversions best describes what takes place in a battery-powered resistive circuit when the current is flowing?
A: chemical to electrical to thermal Think of problem conceptually. What initiates flow of current in a circuit? The battery. How does it do this? It uses a redox reaction (CHEMICAL) to generate a flow of electrons. The electrons (ELECTRIC) then deliver their kinetic energy to the resistors which dissipates some of this energy as heat (THERMAL).
Q: Which of the following best describes the bonds between Cu2+ and the nitrogen atoms of the ammonia molecules in [Cu(NH3)4]2+?
A: coordinate covalent -when a transition metal binds to a bunch of non-metal molecules and you see those brackets, think coordinate covalent. -ionic bond the nonmental accepts the electrons to become negatively charged. The N is not becoming completely negatively charged. -n this case, the non-metal molecules are sharing their electrons with the transition metal, so its covalent -covalent bc this is sharing e- between non metals
Q: In designing the experiment, the researchers used which type of 32P labeled ATP?
A: gamma32P-ATP told the reaction involves kinase -kinases turn ATP to ADP -REMEMBER ATP has alpha, beta, gamma phosphate groups -the phosphate that gets transferred is the gamma one
Q: What is the role of the solid state catalyst in the Haber process?
A: it increases the amount of ammonia produced per unit time -Catalysts DO NOT INCREASE THE AMOUNT OF PRODUCT FORMED THEY INCREASE THE RATE OF THE REACTION by allowing the reaction to proceed at a lower activation energy.
Why does NH3 displace H2O in the formation of [Cu(NH3)4]2+?
A: it is a stronger Lewis base than H2O and NH3 donates a lone pair of electrons more readily than does H2O other choices: NH3 contains more lone pairs of electrons than H2O -NH3 has 1 lone pair. H20 has 2 lone pairs
Which of the following has the largest mass percent of oxygen?
A: mass percent= molar mass of O in compound/molar mass of overall compound 16/18 x 100= 89%
What are the structural features possessed by storage lipids?
A: three fatty acids ester linked to a single glycerol -triacylglycerols
Q: Why must the person either lean forward or slide their feet under the chair in order to stand up?
A: to keep the body in equilibrium while raising -support comes from the feet, the person is in equilibrium when the center of mass is directly above their feet -if person didn't lean forward or slide their feet under the chair to stand up, the person would fall backward due to the large torque created by weight of body + distance along center of mass -T= rFsin other choices: increase the force required to stand up -NO DUMBY READ THAT OVER, increasing the force would make it harder to stand up wtf -think CENTER OF GRAVITY
Negative focal length
ALWAYS diverging (concave) lens. Diverging lens will ALWAYS be Virtual, upright, and reduced size REGARDLESS if object distance is greater than or less than the focal length. di<0 UV
coordinate number
Coordinate number is the # of bonds that the central ion makes with a neutral atom. (NH3 is neutral, Cu2+ is the central ion)
supersaturated solution
DONT precipitate -but if we scratch or shock them they can form precipitate
Boyles law
P1V1=P2V2 It says that pressure increases as the volume decreases
silica gel is
POLAR so if this is stationary phase, those with polarity will increase affinity for stationary and non polar would elute first
Heinsberg uncertainty principle
This has to do with the position of an electron in space. It states that the exact position and momentum of a particle cannot both be known at same time. In fact, the uncertainty of a position and momentum is inversely proportional. The more accurately an object's position is known, the less accurately its momentum can be known, and vice versa. This principle impacts study of small particles such as electrons most strongly.
DO NOT FORGET ALL THE WORK EQUATIONS
W= F x d PE= mgh KE= 1/2 mv^2 static friction: Ff= usF(normal) kinetic friction: Ff= uKF(normal) springs: F= -kx PE elastic: 1/2 kx^2 Power (work): P= W/t center of mass gravity: m1x1+m2x2/m1+m2
Qsp>Ksp
oversaturated -things will fall out of solution and precipitate
pH=
pH = pKa + log([base]/[acid]) *remember log (1/10)= 10^-1= -1
Two fatty acids ester linked to a single glycerol plus a charged head group
phospholipid
tertiary structures
refers to the overall folding of the entire polypeptide chain into specific 3D shape
