Diagnostic MCAT (science) Flashcards
What letter is equillibrium constant?
K
What is pK and what does the size of the number indicate?
pK = -log(K)
Dissociation constant of acid into its conjugate base or vice versa.
Smaller number indicates stronger acid/base.
What is the formula that ties in the equillibrium constant of acids and bases?
Ka * Kb = Kw
Kw applies to water, ig this is only for water.
Put 50cm^2 into m^2.
.005 m^2 (4 decimal places)
Relate capacitance, voltage, and charge.
Relate average current, time, and charge.
Q = CV
I = Q/∆t
If a capacitance or voltage is changed in a problem and the respective new value of the new capacitance or voltage is asked, what is the equation?
C1V1=C2V2
Relate wavelength to frequency 2 ways.
What is the speed of light?
f = 1/λ
(inverse relationship)
f*λ = c(speed of light)
c = 3E8 m/s
Protonation and deprotonation
Protonation: Addition of a proton (H+)
Deprotonation: Removal of a proton (H+)
As pH is raised, the most acidic group ____ ____.
deprotonates first
This is because the most acidic group has the lowest pKa, meaning it is the most willing to lose a proton (H⁺) at lower pH values.
Acidity and pKa are ____ ____.
inversely related
What change in physical state (ex. solid to liquid, liquid to gas, liquid to solid, gas to liquid) takes the most energy/heat.
Vaporization (liquid to gas)
Enantiomers
Pairs of chiral molecules. Same physical/chemical properties.
Ex:
Dextrorotatory (rotates light clockwise, labeled (+)), the other being Levorotatory (rotates light counterclockwise, labeled (-)).
Chirality
Can’t be superimposed on another molecule, same size but assymetrical. (Right glove left glove).
Same atomic formula and connectivity.
Similar physical and chemical properties but can differ in different conditions.
Refers to one molecule.
Blood flow speed is 30 cm/s in a 1.6 cm diameter tube. Tube is reduced to .8 cm diameter, what is the new speed?
A1V1=A2V2
Area = pir^2
Answer is 120 cm/s
Does Ca 2+ have an electron configuration equal to that of a noble gas? (Need periodic table)
Yes, loses two electrons through positive 2 charge, move 2 columns left on the periodic table.
6C12 (6 on top 12 on bottom of Carbon)
What about 14 on bottom?
How many protons electrons neutrons?
Protons:6
Neutrons:6
Electrons, depending on + or -, if C+, 5 electrons.
If Carbon has 14, then 6 protons, 8 neutrons.
Electronegativity
Periodic table trick…
Ability for atom to attract electrons toward itself in chemical bond.
Increase in electronegativity as moves to the right and up (periodic table).
Temperature’s relationship to volume…
Pressure relation to volume…
As temp increases volume increases (if heat is added).
Inverse relationship –> Doubling pressure will halve the volume.
Formula relating moles volume and concentration.
moles = CV –> moles = volumeconcentration
Le Chateleirs Principle.
Formula with Ki, E, EI and I.
In a reversible process, the application of stress in the system will prompt a response that relieves stress.
Ex. Adding more [I] (inhibitor) will prompt the production of more [EI] (enzyme substrate inhibitor).
Ki = ([I][E])/[EI]
[E] + [I] <–> [EI]
Polarity relationship with water solubility…
As polarity increases so does water solubility.
Reasoning:
Polarity increases water solubility because polar molecules can form hydrogen bonds or dipole-dipole interactions with water, which is a highly polar solvent. These interactions allow the polar molecules to dissolve more easily by breaking into the water’s hydrogen-bonded network.
RC(=O)R ——> RCH(OH)R
What happened here?
C(=O) = carbonyl
H(OH) = hydroxyl
carbonyl to hydroxyl group.
What kind of reaction is this:
RC(=O)R ——> RCH(OH)R
Reduction reaction.
Addition of electrons and protons.
When more electronegative atoms are replaced with less electro negative atoms on a carbon, the oxidation state decreases (becomes more negative) because the carbon “gains” electrons because the pull is less intense.
What are flavins?
Group of organic compounds based on a molecular structure derived from isoalloxazine —> tricylcic ring system.
Isoalloxazine ring?
tricyclic ring
When coupling a charged particle against a concentration gradient, what happens?
Energetically costly, makes reaction less exothermic.
Pyrrole ring
1 nitrogen corner, 4 carbon corners.
Aromatic compounds
A molecule that contains a conjugated pi electron system.
Cyclic planar structure with delocalized electrons in conjugated pi bonds.
Increased stability.
What is the volume of 1 mole of gas at 0 degrees C, 1atm?
AKA STP.
How is it derived?
22.4L
22400 cm^3
Derived from PV=nRT
P = 1atm
V = Volume (L)
n = 1 mol
R = ideal gas constant .0821L
T = 273.15K
Equation that connects volume of gas, volume of 1 mole at STP, and moles.
moles = (volume of gas)/(volume of 1 mole at STP)
When will fluorescence radiation be produced, which has to be higher?
Energy of absorbed radiation or energy of fluorescence radiation?
Energy of absorbed radiation.
CD Spectroscopy
CD (circular dichroism) spectroscopy is a technique used to study the secondary structure of proteins and other chiral molecules by measuring the difference in absorption of left- and right-circularly polarized light. It helps identify structural elements such as alpha-helices, beta-sheets, and random coils by analyzing their characteristic absorbance patterns in the far-UV region (typically 180-250 nm). In the context of the MCAT, understanding CD spectroscopy is relevant for recognizing how proteins fold and how their structures relate to function.
Problem mentions where chirality arises from and mentions protein folding or amino acids, what is most likely the answer?
alpha carbon
(acarbon)
As time goes on gel is broken down, what is proteolysis?
Breaks down proteins into smaller fragments
TMPT is a transferase
Transferase: A transferase is a type of enzyme that catalyzes the transfer of a functional group (e.g., methyl, acyl, phosphate, or amino group) from one molecule (the donor) to another molecule (the acceptor).
Transferase does not result in the loss of mass when dealing with the same molecule.
All steroid hormones are derived from…
Cholesterol
Ex. of a steroid hormone: progesterone.
Chromatography
Technique used to separate, identify, and purify components of a mixture based on their differences in chemical/physical properties.
Chromatography –> elution step
Separation
Chromatography –> affinity
Identify/purify
In chromatography, what is the most important part of a compound that separates the ligand/protein?
The hydrophobic/hydrophilic regions.
How to tell if something being tested is in its native state?
If the binding affinity was similar after the reaction to what it was before the reaction.
Carboxyl Group
C(=O)OH –> acidic
More acidic than hydroxyl and carbonyl groups.
Hydroxyl group
OH
can act as a weak acid
Amine group
NH2 or NH
generally basic
Rank order acidity:
Carboxyl group
Hydroxyl group
Amine group
Carboxyl>hydroxyl>amine
Most acidic is carboxyl
Acidity and bonding
Stronger acids have weaker bonds to H+ and form more stable conjugate bases.
Imidazole
Imidazole is a heterocyclic aromatic compound with the molecular formula C3H4N2.
5 membered ring structure.
6 pi electrons
Ammonium molecular structure.
Acetate molecular structure.
Ammonium: NH4+
Acetate: CH3CO2-
Anion exchanges vs cation exchanges
Anion exchange: negatively charged.
Cation exchange: positively charged.
(Chromatography)
Imidazole in histidine side chain…
The imidazole group in histidine’s side chain is a unique functional group that imparts chemical versatility, enabling histidine to act as a proton donor, acceptor, and metal ligand.