Exam 3 Flashcards
Where can peptide bonds rotate
N-aC
N-C(carbonyl) angle
Omega
C(Carbonyl)-aC angle
Psi
aC-N angle
Phi
The amino acid sequence
Primary structure
Local folded structure. Stabilized H-bonds between backbone amides
Secondary structure
Interactions between regions of secondary structure. Stabilized by the hydrophobic effect and intermolecular interactions between side chains.
Tertiary structure
Interactions between multiple folded polypeptide chains.
Quaternary structure
Molecules move in straight lines; their directions is random
KMT or gases(kinetic molecular theory)
Molecules are small. The volume of the molecule is much smaller than the volume of the container.
KMT of gases
Molecules do not attract or repel each other.
KMT of gases
Molecules experience elastic collisions
KMT of gases
The mean kinetic energy is proportional to the temperature in kelvin
KMT of gases
T is proportional to E =
1/2 mxu^2 (mass of molecule in kg) (root mean square speed of molecule)
U(rms)=
Square root of 3RT/M R=8.314 M=Molar mass T=temperature in kelvin
Leakage of gas through a small opening
Effusion
Diffusion
Even distribution of all gases throughout a volume of space
Light molecules effuse and diffuse faster than heavy molecules
True
Square root M2/M1 M=molar mass
Grahams law(measuring effusion of two gases)
1 atm =
760 torr
Standard temperature and pressure values
T=0 C P= 1atm
density =
nM/V and PM/RT
Moles are proportional to volume
True
The pressure a gas would exert if alone in a container
Partial pressure
Fraction of each gas in both terms of pressure and of moles
X=Pi/Pt=ni/nt
Mole fraction
Pi=XiPt
True
Energy is required to disrupt molecular interactions (vaporization, fusion, sublimation)
Endothermic
Energy is released, when intermolecular interactions are formed (condensation, freezing, sublimation)
Exothermic
Heat capacity per gram
q/m(change in T) q=heat transferred
Specific heat capacity
Heat capacity per mole
q/n(change in T)
Molar heat capacity
Vapor pressure increases with temperature
True
Strong IMFs mean high boiling point and low vapor pressure
True
A minor component in a solution
Solute
A major component in a solution
Solvent
Mass of solute/mass of solution
Mass fraction
Mass fraction x 100%
Mass %
Moles of solute/moles of solution
Mole fraction
Moles of solute/liters or solution
Molarity
A solution that contains less solute than is soluble under those conditions
Unsaturated
A solution that contains the maximum amount of solute that is soluble under those conditions
Saturated
A solutions that contains more than the maximum amount of solute that is soluble under those conditions
Supersaturated
Soluble in all proportions
Miscible
Gas solubility decreases at temperature increases
True
Cg=kPg Cg=amount of gas dissolved Pg=partial pressure of gas above the solution
Henry’s law
