chem/phys mcat practice exam 1

competitive inhibition

inhibitor binds to same active site as substrate. Vmax stays the same and Km increases

uncompetitive inhibition

inhibitor binds to ES complex at an allosteric site. Km decreases (because ES is constantly being drained out so we make more by binding more E to S), Vmax decreases

noncompetitive inhibition

inhibitor binds to allosteric site whether or not substrate is yet bound. Km stays the same, Vmax decreases

mixed-type inhibition

inhibitor acts as competitive or uncompetitive in terms of binding to an E or ES complex and how the Km is changed. but it binds at an allosteric site. Km will increase or decrease depending on if it acts as competitive or uncompetitive (E or ES binding). Vmax always decreses

axes of lineweaver-burk plot

x axis: -1/Km

y axis: 1/Vmax

linear

2:0 or 2:3

trigonal planar

3:0

bent (120 degrees)

2:1

tetrahedral

4:0

trigonal pyramidal

3:1

bent (109.4 degrees)

2:2

trigonal bipyramidal

5:0

seesaw

4:1

t-shaped

3:2

octahedral

6:0

square pyramidal

5:1

square planar

4:2

uracil

thymine

adenine

guanine

cytosine

equation to find electric field magnitude

E (units: v/m)= change in V (voltage) / D (distance)

equation for energy in a capacitor

E=(1/2)(QV) or E=(1/2)(CV²)

log(1)

0

log(2)

0.30

log(3)

0.48

log(4)

0.60

log(5)

0.70

log(10)

1.00

log(0.1)

-1.00

log(0.01)

-2.00

log(0.001)

-3.00

henderson-hasselbach equation

pH=pKa + log (A-/HA)

what is the delta G of this rxn: exothermic and decreased disorder

spontaneous at low temperatures, nonspontaneous at high temperatures

what is the delta G of this rxn: exothermic, increase in disorder

always spontaneous

what is the delta G of this rxn: endothermic, decrease in disorder

never spontaneous

what is the delta G of this rxn: endothermic, increase in disorder

spontaneous at high temperatures

what is the delta G of this rxn: requires energy at any temperature

nonspontaneous

converting energy, wavelength, frequency, and the speed of light

E=hv, c=λν

absorbance units

no units!

how to find concentration of enzyme at calculated absorbance

calibration/standard curve based on equation

what makes up a blank?

no reactants or products; just a solvent

relate energy to power and time

E=Pt

amplitude

how high a cosine or sine wave goes

period

a full cycle of a cosine or sine wave

phase difference

the x difference between two crests of the same type of wave

crest

the name for the top of a sine or cosine wave

constructive interference; what is it and what is its effect

occurs when there is no phase difference between 2 cosine or 2 sine waves; produces a third wave which combines their amplitudes

phase-shift

cosine or sine wave moving left or right, affecting whether the crest is up or down at a certain spot

deconstructive interference

occurs when there is a phase difference between 2 waves; subtract the amplitudes from each other

relationship between LDF forces and molecule size

larger molecules have more electrons, making their e- cloud more easily distorted, making it more more polarizable, leading to stronger LDF

acid dissociation constant equation

Ka=([H+][A-])/[HA]

how many C in propane

3

how many carbons in butane

4

acyl group

benzyl group

acetone

how are beta sheets held together

intermolecular hydrogen bonding

how are alpha helices held together

intramolecular hydrogen bonding

ionic radius periodic trend

decreases going up, increases with negativity (cations will shrink, anions swell)

relationship between Ka, pKa, and acidity

increased Ka = decreased pKa = releases proton more readily = stronger acid

positron decay (B+) ; same trend as electron capture

one proton is converted into a neutron

alpha decay

emits 2 protons and 2 neutrons

B- decay

neutron is converted into a proton and an electron

gamma decay

photon is released as energy

G and C hydrogen bonding

a and t hydrogen bonding

relate the electric field to voltage and distance (capacitor)

E = change in v/d

electric field within a conduction material at equilibrium

0