CHEM/PHYS AAMC Free Sample (SCORED)

Bose-Einstein Principle

a collection of atoms cooled close to absolute zero will coalesce into a single quantum state.

presence of a reducing sugar makes _______

a compound susceptible to oxidation and imparts aqueous compatibility

dimer

a compound whose molecules are composed of two identical monomers

nuclear fusion

a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.

strong nuclear force

a powerful force of attraction that acts only on the neutrons and protons in the nucleus, holding them together

buffer solution

a solution made from a weak acid and its conjugate base that neutralizes small amounts of acids or bases added to it OR a weak base and its conjugate acid

As the pH is raised, the most ___ group deprotonates first

acidic

anhydrase

an enzyme that promotes the removal of water from a chemical compound

Imidazole

as mentioned is the R group of His and important for His-tagging. Derivatives of this group are part of a class of anti-fungals useful for "His-Tags" in column chromatography, used to elute out proteins basically that bind to Nickel

optically active

compound that rotates the plane of polarized light -asymmetric in such a way that it is impossible to superimpose the original molecule upon its mirror image

strong acids and bases

dissociate completely in water

movement of a charged particle against its concentration gradient is ...

energetically costly -coupling the two processes: the redox reaction between NADH and ubiquinone and the movement of Na+ up a concentration gradient makes the overall process less exothermic (catalyst Na+-NQR)

Protease

enzyme that breaks down proteins

Transferases

enzyme that transfers functional groups from one substrate to another --> total mass change = 0

Pressure is the ratio of the ________________________.

force applied perpendicular to a surface and the area of the surface P= F/A

Acetate Molecular Formula

CH3CO2

Carbonate Molecular Formula

CO3 2-

If the wavelength of a beam of light were to double, how would that affect its frequency?

frequency would be halved **given product b/t wavelength and frequency is constant when light travels through a certain medium

Le Chatelier's Principle

in a reversible process, the application of stress to the system will cause the system to respond in a way that will relieve the stress -explains the changes in the temperature, volume, concentration, and pressure will shift the equilibrium in a predictable manner

using more enzyme will not...

increase yield of products **will only affect rate of reaction

Protease inhibitors

inhibit the processing of large viral proteins into individual components

Capacitance

is inversely proportional to the separation d between parallel plates C= (e0 x er x A) / d *a decrease in separation corresponds to an increase in the capacitance *given that charge on the capacitatoot is directly proportional to the capacitance, an increased capacitance results in a increase in the charge as long as the power supply voltage is constant

if a compound is lipophillic

it will not dissolve in aqueous layer (extraction), rather it prefers to dissolve in organic solvents

Detergents

liberates a protein from a membrane so that it might be isolated. The combination of large hydrophilic and hydrophobic regions allows detergent to function to this capacity

Multiple hydrolysable linkages would facilitate

metabolism

pyrrole

molecular formula: C4H5N

aggregation

molecular weights of the bands decrease

Hill coefficient less than 1

negative cooperativity ex: as one MCS oligomer binds to the ATPase, it makes it more difficult for others to bind, leading to inhibition

Hill coefficient = 1

no cooperativity -ex: a single MCS oligomer binds to ATPase, leading to inhibition

Heisenburg Uncertainty Principle

one cannot know both the momentum and position of an object with absolute certainty.

Hill coefficient greater than 1

positive cooperativity ex: when one MCS oligomer binds to the ATPase, it makes it easier for others to bind, leading to inhibition

Heterocyclic

ring shaped carbon chain which has to have at least one atom that isn't carbon in the ring

Anion exchange chromatography

separates proteins with different negative charges (or negative vs positive/neutral charge) -negatively charged proteins will bind to a positively charged matrix -**its separation method is not based on selective binding to the column based on a functional group-specific chemical reaction or ligand-receptor interaction

cation exchange chromatography

separates proteins with different positive charges (or positive vs negative/neutral charge) -positively charged proteins (basic) will bind to a negatively charged matrix (acidic) -**its separation method is not based on selective binding to the column based on a functional group-specific chemical reaction or ligand-receptor interaction

chirality is important for _______

specific binding to other compounds

Hess's law of heat summation

states that if you add two or more thermochemical equations to give a final equation, then you can also add the heats of reaction to give the final heat of reaction --> the heat of reaction will sum and be the same

Permittivity

the ability of a substance to store electrical energy in an electric field.

Proteolysis

the number of lower molecular weight bands with time increases and the original band at the highest molecular weight diminishes with time

flourescence

Can occur when the absorbed radiation has a photon energy larger than the photon energy of the radiation emitted through fluorescence. The photon energy is inversely proportional to the radiation wavelength -->E= hc/ wavelength = hf ------> Energy of a photon = [plancks constant (6.626 x10^-34 Js) x speed of light (3x10^8 m/s)] / wavelength (nm)

Average current equation

Charge of capacitor / Time units [amplitude A]

continuity equation (fluids)

**works under the assumption that the flow of the fluid in = fluid out (Q1=Q2) A1V1=A2V2

Pauli Exclusion Principle

-An atomic orbital may describe at most two electrons, each with opposite spin direction -two or more identical fermions, e.g. electrons, cannot occupy the same quantum state

flow rate (Q)

The volume of fluid that moves through a surface in a given unit of time. Volumetric flow rate: Q=vA or Q=V/t *v= velocity of fluid *A= area of cross section of the space fluid is moving through *V= volume of fluid *t= time elapsed

affinity chromatography

uses a bound receptor or ligand and an elutent with free ligand or a receptor for the protein of interest

common ion effect

-a decrease in the solubility of an ionic compound caused by the addition of a common ion -visual result seen from shifting the equilibrium; a shift in equilibrium results in the creation of either more products or reactants being created -in laboratory experiments, used to crash out specific compounds in a molecule ---> for example, if we have silver chloride, AgCl, and silver sulfate, Ag2So4, in solution and ONLY want to take out AgCl, we could think about our example above and add NaCl to crash out the AgCl in solution

Kd (equilibrium dissociation constant)

-a measure of the tendency of a larger complex to separate (dissociate) into its smaller parts - dissociation rxn: AxBy <--> Ax + By - Kd= ([Ax][By])/[AxBy] -ex. represent ligand concentration and should be calculated when 50% of the receptors are bound to ligands **the smaller the Kd, the more tightly bound the ligand is and therefore the higher the affinity between the ligand and the receptor

Ki - Inhibitor Constant

-type of equilibrium dissociation constant (Kd) that represents the equilibrium binding affinity for a ligand that reduces the activity of its binding partner -represents the concentration at which the inhibitor ligand occupies 50% of the receptor sites when no competing ligand is present

The probability of fusion increases with:

-with the decrease in the average distance between fuel particles that enables attractive nuclear forces to overcome the repelling nuclear forces acting at medium and long distances -with the increase in density of fuel

area under the force-distance line

= work generated ** A= 1/2xFxd

Hill coefficient

A measure of cooperative interaction between protein subunits

ligand

A molecule that binds specifically to a receptor site of another molecule.

salt bridge

A tube that allows the slow transfer of ions and maintains the neutrality of the electrolyte solutions. ex: negatively charged phosphate with positive side chain of an AA

Area of a circle formula

A=πr²

Newton's Second Law

Force = mass x acceleration

pi stacking/aromatic stacking

Double bonds are pi bonds. So when you have a phenylalanine ring, for example, it turns out that the molecule isn't completely flat. The pi electrons in the double bonds form a "ring" above and below the phenylalanine ring. So when you stack two phenylalanine rings on top of each other, these two pi electron regions will overlap.

what is the only L-Amino Acid that is NOT optically active?

Glycine

formate molecular formula

HCO2

bicarbonate molecular formula

HCO3-

Ki on semi-log plot

Ki is the inflection point of the sigmoidal curve because by definition Ki is the concentration of the inhibitor at which the reaction rate is half of the maximum reaction rate

What makes a compound more soluble in water?

Polar lone pair that can accept a hydrogen bond from water

hydrostatic pressure

Pressure exerted by a volume of fluid against a wall, membrane, or some other structure that encloses the fluid. P=pgd [Hydrostatic Pressure = Liquid Density x gravitational acceleration x depth)

Charge on a capacitor equation

Q = CV -V is the voltage (V) difference between the two plates of the capacitor, not necessarily the voltage of a battery in the circuit -For a given voltage, larger C means greater storage charge units Q = mC units C = Farads [F]

indole

R group of tryptophan

common ion effect: NaCl and AgCl example

Say we have fully dissolved NaCl in an aqueous solution... leaving no solid NaCl left in the solution THUS, there are now both Na+ and Cl- ions in the solution [NaCl <--> Na+ + Cl-]. If we were to dissolve silver chloride, AgCl, in the same glass [AgCl <--> Ag+ + Cl-], the equilibrium of the reaction shifts to the left. -Le Chatlier's Principle dictates the equilibrium of a reaction to shift in whichever direction is needed to counteract the effect. -In THIS situation, the effect is the surplus of the reactant Cl-. -AS A RESULT, because the reaction favors the left side, AgCl, its solubility is decreased ---> NaCl and AgCl dissolve to form Na+, Ag+, and Cl- ions. Because NaCl and AgCl share the common ion Cl-, all Cl- ions in solution contribute to the equilibrium of AgCl

Esterification

The reaction of an alcohol with a carboxylic acid to produce an ester and water.

epitope

Small, accessible portion of an antigen that can be recognized.

Formula for tension

T = mg + ma

Solubility and pH

The common ion effect is also present in buffer solutions. Addition of excess ions will alter the buffer solution. Therefore the common ion effect takes a role in pH regulation. According to Le Chatlier's principle, the addition of more ions alters the equilibrium and shifts the reaction to FAVOR the solid or deionized form. --> in the case of an acidic buffer, the hydrogen ion concentration decreases, and the resulting solution is less acidic than a solution containing the pure weak acid ---->ex. HCN <---> H+ CN- The addition of cyanide ions (CN-) will suppress the ionization of hydrogen cyanide (HCN) and shift its equilibrium to the left. The percent dissociation of the hydrogen cyanide will decrease and therefore decrease the H+ ions and increasing the pH of the solution.