Biochem Lecture 1

A chemical bond that involves the sharing of electrons between two atoms

The energy required to break a chemical bond (a measure of bond strength)

An electrostatic interaction b/w an electronegative atom and the hydrogen atom covalently bonded to another electronegative atom

Measures the ability of an atom to attract electrons to itself w/in a covalent bond

Electrostatic interation b/w 2 atoms or molecules w/ formal charges

Describes the tendency of a non-polar solute to come together when placed in a polar environment

The component of the total energy of a system that can do work at constant temperature and pressure

The amount of free energy released (-) or absorbed (+) in a reaction at constant temperature and pressure

A rxn that, given a set of initial conditions, will proceed in the direction of the production of products to reach equilibrium

A measure of the heat conten of a given molecule or system

A measure of disorder and randomness

The point in a chemical reaction where the rate of the forward reaction is equal to the rate of the reverse reaction

The ratio of the concentration [] of products over the concentration of reactants once equilibruim has been achieved

• 1. Covalent bonds - generally unchanging in proteins
• 2. Non-covalent bonds - 'weak' bonds that cause interactions b/w macromolecules

• Ionic bonds
• Hydrogen bonds
• Hydrophobic interation
• Van der Waals interactions

Changes about a single bond that are adopted w/out breaking covalent bonds (staggered, eclipsed, etc)

changes about a double bond that can only be adopted by breaking bonds (cis and trans)

H<C<N<O

The lone pair or partial negative charge (the e.n. atom other than H)

The Hydrogen with the partial positive charge

Arises when an atom has more (-) or less (+) valence electrons in the Lewis structure than the bare atom

• Bare Oxygen owns 6 electrons, so:
• ~owns 7 if 1 bond = negative (anion)
• ~owns 6 if 2 bonds = neutral

• Bare Nitrogen owns 5 electrons, so:
• ~owns 4 if 4 bonds = positive (cation)
• ~owns 5 if 3 bonds = neutral

• Q= charge of the two ions
• r = distance b/w the two ions
• E = dielectric constant

• The ability of a solvent to shield ions from each other.
• ~E is HIGH for polar solvents
• ~E is LOW for non-polar solvents

• Rxns with a negative delta G
• Rxns that release free energy, spontaneous

• Rxns with a positive delta G
• Rxns that absorb free energy, nonspontaneous

Enthalpy (H), Entropy (S), and Temperature (assumed constant)

• Rxns with a negative delta H
• Rxns that feel hot (temperature of surroundings is increased)

• Rxns with a positive delta H
• Rxns that feel cold (temperature of surroundings is decreased)

If the order in a system decreases, the change in entropy or degrees of freedom is positive

If the order in a system increases, the change in entropy or degrees of freedom is negative

Products will predominate at equilibrium

Reactants will predominate at equilibrium