Aqueous Chemistry Flashcards
What do all of the four major classes of biomolecules have in common?
all made up of mainly: C, N, O, & H
What atom is the most important and versatile? Why?
Carbon! because it has 4 valence electrons and therefore can form chains
what is a covalent bond?
2 atoms SHARING electrons
strong, require a lot of energy to break
geometry of carbon bonding…
sp3, tetrahedral–free rotation defines conformation
sp2, trigonal planar no free rotation, defines configuration
what is nice about space fill models?
show the size of van der waal radii
what is the most important property of biomolecules? why?
polarity! because it tells the positive and negative nature of molecules in space. It is based on the EN of atoms
Define amphipathic
molecules that contain polar and non-polar groups
Ionic interactions
attractive or repulsive electrostatic force
strength depends on coulombs law
van der waals interactions
collection of very weak attractive forces based on dipole or induced dipole interactions of closely spaced atoms
becomes significant in larger numbers where complimentary surface can contribute to bonding specificity
Hydrogen bonds
H shared by two EN atoms; partial covalent character
depend on linearity and polarity of the environment
very directional, contribute to biological specificity
Tell me about water!! (6)
it is the most important molecule!!
it is bent and very polar
forms hydrogen bonds which impart high melting and boiling points, surface tension, dielectric constant
orients itself differently depending on what it is next to
104.5 degrees not 109.5!!
Hydrogen bonds are strongest when three atoms are in a line
What are the relative bond strengths in biomolecules?
covalent>ionic>hydrogen>van der waals
What type of molecules is water a good solvent for?
polar ionic because it disrupts crystal structure
not non-polar!!
What is the hydrophobic effect?
The hydrophobic effect is the observed tendency of non-polar substances to aggregate in aqueous solution and exclude water molecules.
what is the thermodynamic explanation for this effect?
the decreased entropy at the non-polar solute interface is not compensated for by a lower enthalpy of solute interactions
However the total area of contact is less is favoured
