Chemical Interactions in Biology: Bonds, Polarity, and Salt Bridges

Chemical interactions

Interactions that dictate how biology occurs.

Chemical Bonds

Interactions between atoms that keep them close together.

Covalent Bond

Interaction where two atoms share valence electron(s).

Ionic Bond

Bond between positively and negatively charged atoms (full charges on atoms from electron exchange allow bonding).

Polarity

Unequal sharing of electrons in a chemical bond, resulting in partial charges on the involved atoms.

Electronegativity

Tendency for an atom to attract electrons towards itself (over other atoms in a chemical bond).

Dipoles

Chemical bonds with positively and negatively charged parts (atoms).

Ion-Dipole Interactions

Ionic charges (cations and anions) and opposite partial charges (dipoles) interact.

Hydrogen Bonding

H-bond donor: Electronegative atom covalently bonded to hydrogen contributed to the H-bond interaction.

What interactions make up a salt bridge?

Combination of H-bonding and ionic interaction; a strong biochemical interaction found in proteins.

Van der Waals Forces

Weak interactions that occur between molecules.

Dipole-Dipole Interactions

Interactions between polar molecules where positive and negative ends attract.

Dipole-Induced Dipole Interactions

Interactions that occur when a polar molecule induces a dipole in a nonpolar molecule.

London Dispersion Forces

Weak attractions that occur due to temporary dipoles in molecules.

Transient dipole induction

A temporary dipole that occurs in nonpolar molecules due to fluctuations in electron distribution.

Induced Dipole-Induced Dipole Interactions

Interactions that occur between two nonpolar molecules when one induces a dipole in the other.

What are salt bridges?

A strong biochemical interaction that provides structure to proteins.

Molecular Level

Refers to interactions at the level of molecules.

Cellular Level

Refers to interactions at the level of cells.

Organismal Level

Refers to interactions at the level of entire organisms.

Chemical interactions vary in strength

Different types of chemical interactions have varying degrees of strength.