C/P Review Flashcards
What does A represent?
Activation energy without enzyme present
What does B represent?
Lowered activation energy due to an enzyme being present
A molecule that REDUCES is a ____ agent
oxidizing agent
List 3 ways in which you can see if a molecule has been oxidized
look for….
- additional oxygens
- fewer hydrogens
- carbons that have additional bonds to oxygen
Proteins that are more stable have [higher/lower] melting points
Higher
higher melting point = more stability
If a question is asking which protein is more stable, it is likely the one with a higher melting point, so look for this info
If a molecule is gaining electrons to carry, it is being [reduced/oxidized]
Reduced
reduction = gaining electrons to REDUCE the CHARGE
The process of changing from an optically active compound into an optically inactive compound or mixture. Optically active compounds (which consist of only one enantiomer) are converted into an equal mixture of enantiomers with zero optical activity.
racemization
True or False
Racemeization requires substitution at a chiral center
True
An achiral compound with several chiral centres but no optical activity due to an internal plane of symmetry. Superimposable on its mirror image
meso-compound
The ability of a substance to rotate the plane of polarization of a beam of light that is passed through it.
optical activity
Compounds that are optically active contain molecules that are chiral, unless it is a meso-compound
Name the isomeric relationship
____ rotate the plane of polarized light in opposite directions
Enantiomers
Organic compounds in which two chiral carbons are present and those two are similar. Have zero net rotation of plane polarised light.
mesomer
A process in which the configuration of an atom is changed. If the atom in question is a stereocenter, ____ usually (but not always) changes R absolute configuration into S, and S into R. ____ can also convert cis into trans, or trans into cis.
inversion of configuration
If the chiral carbon is not changed in the reaction, a molecule’s sterochemistry is conserved
conservation of sterochemistry
chiral centers are ____ hybridized
sp3
the Rf of a compound represents the distance traveled by the [solvent front/compound] divided by the distance traveled by the [solvent front/compound]
the Rf of a compound represents the distance traveled by the compound divided by the distance traveled by the solvent front
A lower Rf value suggests that the molecule in question is more [polar/nonpolar] and therefore [more/less] traveling bc the molecule has [lower/higher] affinity for the stationary phase
A lower Rf value suggests that the molecule in question is more polar and therefore less traveling bc the molecule has higher affinity for the stationary phase
True or False
Enzymes can affect ΔS
False. ΔS is the change in entropy. Enzymes do not affect thermodynamics at ALL.
If a question asks if an enzymes affect anything involved in the Gibbs Free energy equation the answer is NO
What’s the acronym that can help you remember the colors of vivisble light in order of increasing energy and frequency.
ROYGBV
400nm-700nm
Violet has the shortest wavelength and the highest frequency in the visible range
An order of chemical reaction in which the rate of the reaction depends on the concentration of only one reactant, and is proportional to the amount of the reactant.
1st order kinetics
chemical reactions wherein the sum of the exponents in the corresponding rate law of the chemical reaction is equal to two. The rate of such a reaction can be written either as r = k[A]2, or as r = k[A][B].
second order kinetics
A chemical reaction in which the rate is constant & independent of the concentration of the reactants
zeroth order reactions
globular proteins are [water/lipid] soluble, which means that amino acids wiht hydro[phobic/hilllic] side chains are found on their exterior
water-soluble, hydrophillic
When G > 0, a reaction is [spontaneous/nonspontaneous]
**non**spontaneous
## Footnote
Given **ΔG = ΔH - TΔS**. When a problem gives you a hypothetical reaction and asks you determine its spontaneity given its H, T, or S values, just imagine large values in this equation
A value of K(eq) > 1 suggests that the ΔG° is [greater than/less than] 1
What is the equation for determining the pH of a substance given its concentration of hydrogens?
pH = -log[(H+)]
Given that the stomach contains 0.21N HCl, what is the concentration of hydrogens? What is the pH?
H+ concentration = 0.21N
pH = -log(0.21)
N in the context of acids is = to H+ per liter of solution.
Remember: pH = -log[H+]
In a fractional distillation, two molecules may have very similar molecular weight but have different levels of….
(there can be multiple answers)
intermolecular forces and branching
IMF takes importance
If lung elastance is the resistance to stretch, would increased elastance be counteracted by increased pressure per unit volume OR increased work by the intercostal muscles?
increased work by the intercostal muscles
increased elastance = breathing will take more work
to counteract decreased lung compliance (the ability of the lungs to expand), work done by the muscles to expand the lungs must increase
Energy stored in an object due to a force that temporarily changes its shape, such as squashing or stretching
elastic energy
Arteries are more elastic than veins becuase…
Because of their thicker walls
remember: elasticity is the ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness.
The ability of an object or material to resume its normal shape after being stretched or compressed; stretchiness.
elasticity
Decibles are measured on a log scale, thus an increase of 10dB is a ____ increase, and an increase of 20dB is a ____ increase
10x, 20x
Proteases are ____, cleaving only L-amino acids
sterospecific
L-amino acids are naturally occuring ones
threonine and serine both have [polar/nonpolar] uncharged side chains that contain ____ groups
polar uncharged sidechains that contain hydroxyl groups
What is the trend of the acceleration at part 7 given the graph?
The acceleration is increasing in the negative direction
work = ….
Power (watts) x Time (seconds)
in Joules or KJ
In a cation exchange chomatography, the mobile phase will have [positve/negative] ions binding to the beads
positive
cation exchange chromatography has (-) charged resin
cation refers to the ATTRACTED molecule
Resistance can be found via Ohm’s law, which is….
V = IR
Voltage = Current x Resistance
would be R = V x I to find resistance
What’s the difference between ΔG°rxn and G‡?
ΔG°rxn refers to Gibbs free energy, where G‡ refers to activation energy.
Enzymes only affect G‡
What are the two ways in which we could increase the rate of a catylytic reactionn?
1.) Increasing substrate concentration
2.) Increasing enzyme concentration
The reaction rate when the enzyme is fully saturated by substrate, indicating that all the binding sites are being constantly reoccupied
Vmax
adding susbstate beyond this point will have no effect on reaction rate as the enzyme active sites are saturated
JW Article
The substrate concentration at which the reaction is half of the Vmax
Km
Given this equation, what happens to Km when the substrate concentration is very high?
Enzymes are increasingly binding to substrate, increasing the velocity of the reaction. What reaction order is this?
All of the enzyme’s active sites are occupied by substrate. Adding more substrates at this point is not changing the reaction’s velocity. What order of kinetics is this?
True or False
Enzyme-substrate reactions are reversible
What happens to Km when V0 is equal to half of Vmax?
Km = [S]
Remember, Km is the substrate concentration at which the reaction is half of the Vmax
video
Name the enzyme inhibition
Induces conformational change that prevents the enzyme from forming products
Non-competitive inhibition
non-competitive inhibition changes enzyme ACTIVITY
The binding of this allosteric inhibitor changes the conformation of the enzyme so the enzyme-substrate complex cannot perform catylytic activity. This means the enzyme cannot catylyze a reaction to form a product.
Where do non-competitive inhibitors bind, and what is their effects on Km and Vmax?
- Bind at allosteric site (any region other than active site)
- Does not affect Km
- Decreases Vmax
Non-competitive inhibitors don’t affect the affinity of the enzyme for its substrate (Km) because the active site is not competed for by the inhibitor
However, the Vmax is decreased because increasing the substrate concentration will not overcome the inhibition
Name the enzyme inhibition
This Lineweaver-Burk plot is for which type of inhibition?
Noncompetitive
Name the type of inhibition
Only binds to an enzyme when a substrate is present
Uncompetitive inhibition
only binds to ES complex
This inhibitor complex forms mostly under concentrations of high substrate and the ES-I complex cannot release product while the inhibitor is bound, thus result in reduced Vmax.
Km is reduced because an enzyme’s affininity for its substrate increases
True or False
In both non-competitive and uncompetitive inhibition, the amount of product that is formed decreases
True
Note: the Vmax of both of these inhibitions decreases. For noncompetive inhibition, this is because the enzyme’s catylytic activity is hindered. In uncompetitive inhibiton, this is because the substrate stays bound to the enzyme
A low Km value means….
Only a small amount of substrate is needed to saturate the enzyme, indicating a high affinity for substrate.
Why does an enzyme’s affinity for its substrate increase with uncompetititve inhibition?
Why does Km decrease with uncompetitive inhibition?
Because the inhibitor binds to the enzyme-substrate complex and then changes the enzyme’s conformation, it makes it incredibly difficult for the substrate to become unbound from the enzyme (substrate gets stuck!). Thus, the apparent affinity of the substrate for the enzyme is dramatically increased
This Lineweaver-Burk plot is for which type of inhibition?
Uncompetitive inhibition
This Lineweaver-Burk plot is for which type of inhibition?
Competitive inhbition
In competitive inhibition, why does the Vmax stay the same while the Km increases?
The reaction can eventually reach its Vmax, but it takes a higher concentration of substrate to get it there. The extra substrate makes the substrate molecules abundant enough to consistently “beat” the inhibitor to the enzyme.
A reaction with a large positve ΔH and a large negative ΔS would indicate that the chemical reaction is [spontaneous/not spontaneous]
Not spontaneous.
Given the ΔG = ΔH - TΔS, a large positive ΔH minus a large negative number gives a large positive number as a result, and a positive ΔG means that the reaction is not spontaneous
How can you tell if a molecule is being reduced?
A molecule gains a bond to hydrogen
____ has more entropy than liquids
Gases
entropy = disorder gases have more disorder because their molecules are bouncing all over the place
The change in heat for a given phase is represented by the equation….
q=mcΔT
If a substance is changing phases, this equation’s realionships are no longer valid.
A problem says you have to find the highest period of a sound wave. What equation would you use?
f = 1/T where f is frequency and T = period
What equation represents the relationship between power and intensity? Power and energy?
I = P/A, P = W/t, thus W = Pt = IAt
I = intensity P = power A =area of surface W = work t = time spent listening to sound
occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes
constructive interference
when two waves overlap in such a way that they cancel each other out
destructive interference
photons have a ____ charge
trick question, NO CHARGE
(regardless of what decay its from). Magnetic fields only affect CHARGED particles
the ____ of any system is equal to the pH where exactly **half **of the compound in solution is in the protonated form and half is in the deprotonated form
pKa
Deprotanation occurs at [high/low] pH and [acidic/basic] conditions
Deprotanation occurs at high pH and basic conditions
a portion of a molecule, which may be a functional group, or describe a portion of a molecule with multiple functional groups which share common structural aspects
moiety
indicates the total number of pi bonds and rings within a molecule
degrees of unsaturation
for an MCAT problem, you can just look at the number of bonds that change in the portion of the molecule undergoing transformation, and the number of rings that change
It is important to note that the removal of two protic hydrogens does not result in increasing the degree of unsaturation if the charges are localized on individual atoms
a molecule during a transformation gains 1 pi bonds and loses 1 ring. What is the degree of unsaturation?
0
a chemical addition reaction in which a nucleophile forms a sigma bond with an electron-deficient species.
nucleophillic addition
These reactions are considered very important in organic chemistry since they enable the conversion of carbonyl groups into a variety of functional groups
An electron rich species that can donate a pair of electrons
nucleophile
an electron poor species that can accept a pair of electrons
electrophile
____ substances are Lewis acids (compounds that accept electron pairs), and many of them are Brønsted acids (compounds that donate protons).
electrophilic
____ increases going down the periodic table due to greater size and polarizability
Nucleophilicity
stronger nucleophiles make reaction go [faster/slower]
Faster
A D-sugar has an [R/S] configuration at the last stereocenter in the molecule, while an L-sugar has the [R/S] configuration.
A D-sugar has an R configuration at the last stereocenter in the molecule, while an L-sugar has the S configuration.
IV administration allows a drug to bypass the ____ , the primary organ responsible for drug metabolism
liver
True or False
Drug absorption is poor through the oral and rectal mucosa
True
A problem asks you to find the angle between the pole of a swing carousel that’s moving people in a circular motion and the people sitting in the swing chairs. What equation would you use to solve this problem?
Torque = τ = Fd sinθ
F is the force creating torque, d is the distance from the force to the rotation point, and θ is the angle between F and d.
What is the relationship between Force and Mass
F = ma
A force pointing into the center of the circle
centripedal force
the apparent outward force on a mass when it is rotated
centrifugal force
Think of a ball on the end of a string that is being twirled around, or the outward motion you feel when turning a curve in a car.
All mammallian amino acids except the achiral glycine, all have an L configuration, which corresponds to an [R/S] stereocenter at the alpha carbon.
S stereocenter
True or False
All things undergo forces from higher potential energy to lower
True
Equation for change in potential energy given a charge
ΔPE= qΔd
change in potential energy = charge x change in distance between electrical field/electric plates
Where do electrical field lines point?
Away from a positive charge and towards a negative point
Equation for 2nd order rate law
r = k[A]2
Name the 5 factors that affect the dissociation constant of hemoglobin
- pH
- temperature
- carbon dioxide (CO2)
- 2,3-BPG
- carbon monoxide (CO)
adding any significant acid or base can affect the pH!
True or False
Cells require the same number of NAD+ electron carriers compared to FAD electron carriers, in order to harvest ATP from fatty acids
Cells require more than twice the number of NAD+ electron carriers compared to FAD electron carriers, in order to harvest ATP from fatty acids
Fatty acid catabolism starts in the ____, and is mostly performed in the ____
starts in the cytosol, performed in mitochondrial matrix
fatty acid catabolism = beta oxidation
