S01 WATER AND NONCOVALENT BONDS OBJECTIVES

What is hydrogen bonding?

An interaction between an electron-rich atom with a lone pair (N or O) and an electron-deficient hydrogen.

What is a hydrogen bond donor (HBD)?

A group containing covalently bound X-H where X is an electronegative atom.

What is a hydrogen bond acceptor (HBA)?

A functional group that provides an electron-rich atom to participate in a hydrogen bond.

What does the term hydrophilic mean?

Water loving.

What does the term lipophobic mean?

Lipid hating.

What does the term hydrophobic mean?

Water hating.

What does the term lipophilic mean?

Lipid loving.

What is the hydrophobic effect?

The separation of hydrophobic molecules from water.

What two factors affect the water solubility of biological molecules?

The ability to form hydrogen bonds and the ionization of functional groups.

How does water's dipolar nature affect its interactions with biomolecules?

It forms hydrogen bonds with polar molecules and excludes non-polar hydrophobic molecules.

How does a covalent bond occur?

When two atoms with half-filled orbitals overlap and their electrons align with opposite spins.

How does an ionic bond occur?

When two ions with opposite charges are attracted to form a bond.

How do Van der Waals bonds occur?

Temporary dipoles in non-polar regions induce dipoles in neighboring molecules.

What is enthalpy (H) in thermodynamics?

The heat of the reaction.

What is entropy (S) in thermodynamics?

The randomness of the system.

What is Gibbs free energy (G)?

A thermodynamic variable (G = H - TS) that determines if a chemical reaction proceeds right or left.

How is ΔG used to predict if a reaction occurs spontaneously?

A reaction occurs spontaneously when ΔG < 0.

Which functional group provides an electron-rich atom to participate in a hydrogen bond?

Hydrogen bond acceptor (HBA).

Between methane and ammonia, which is most likely to form a hydrogen bond with water?

Ammonia.

Is sodium chloride (NaCl) hydrophilic or hydrophobic based on its ability to dissolve readily in water?

Hydrophilic.

What phenomenon is demonstrated when avocado oil separates from water to form its own layer?

Hydrophobic effect.

Does glycolysis occur spontaneously or non-spontaneously as an exergonic reaction?

Spontaneously.