Block 1 Equations Cheat Sheet
Thermodynamics
Enthalpy
U = the change in energy
P = pressure
V = is volume
Gibbs Free Energy
Gibbs (G) = free energy of a system
S = entropy (a measure of disorder)
T = temperature
Enzymes
Reaction Velocity
=
Ks = reaction rate
x = reaction order
Michaelis-Menten
Vmax = maximum velocity
Km = half of the maximum velocity
Enzyme Binding
Dissociation Constant
Receptor (R) + Ligand (L) → RL
Resting Potential
Voltage
I = current
R = resistance
Capacitance
q = charge (coulombs)
V = voltage
Particle Movement Down Gradient
AKA, Fick's Law. Measured in Flux (J).
Di = diffusion coefficient
A = cross sectional area
(C1 - C2) = concentration difference
X = distance over which the diffusion takes place
Movement Across Membranes
Px = permeability coefficient
(Xo - Xi) = concentration difference between outside (o) and inside (i) the cell
Membrane Equilibrium Potential (Simplified)
AKA, Nernst Equation.
z = valence (charge of ion, Ca2+ = 2, K+ = 1)
Xo = concentration outside the cell
Xi = concentration inside the cell
Membrane Potential (Multiple Ions)
AKA, Goldman-Hodgkin-Katz. This example considers the flow of Potassium (K) and Sodium (Na) ions.
G = conductance
out = concentration outside membrane
in = concentration inside membrane
Membrane Potential (Steady State)
A modification of Goldman-Hodgkin-Katz using the current equation at steady state. This example considers the flow of Potassium (K) and Sodium (Na) ions.
G = conductance
E = membrane potential
Current Equation (Single Ion)
I = current
G = conductance
(Vm - Eeq) = driving force
Action Potential Conduction
Space Constant
Rm = membrane resistance
Ri = internal resistance (inverse of axon diameter)
Time Constant
Rm = membrane resistance
C = membrane capacitance
Heart Circulation
Mean Arterial Pressure
CO (Cardiac Output) = stroke volume (SV) * heart rate (HR)
TPR (Total Peripheral Resistance) = The resistance of the entire circulatory system
SBP = The contracting pressure, which correlates with the cardiac output (CO). Normally between 90-120 mmHg.
DBP = The arterial pressure when the heart is relaxes, which correlates with total peripheral resistance (TPR). Normally between 60-80 mmHg.
Pulse Pressure
PP = SBP - DBP
SBP = The contracting pressure, which correlates with the cardiac output (CO). Normally between 90-120 mmHg.
DBP = The arterial pressure when the heart is relaxes, which correlates with total peripheral resistance (TPR). Normally between 60-80 mmHg.
Body Fluid Compartments
Indicator Dilution Technique
For finding a compartment volume of unknown size.
Quantity (Q) = concentration * volume
Vi = volume injected
Measuring Blood Volume
Hematocrit = % of blood that is cells
Osmosis and Fluid Shifts
Permeability to Water
Ps = Permeability of solute
Pw = Permeability of water
Osmotic Pressure
σ = permeability to water
c = concentration
R = gas constant
T = the temperature (in k) of the fluid
Fluid Filtration Pressure
Pc = Capillary pressure. Force pointing out from pumping of the heart
Pif = Interstitial fluid pressure. Force pointing in from hydrostatics
p = Plasma colloid osmotic pressure. Force pointing in from proteins (solute)
if = Interstitial fluid colloid osmotic pressure. Force pointing out from proteins (solute) in the interstitial fluid
pH and Blood Buffering
Protons in Solution
Henderson-Hassall Bach
pKa = the point at which half the molecules are protonated
pKa = -log(Ka)
Inheritance in Populations
Hardy-Weinberg
= homozygous dominant
= homozygous recessive
= heterozygous