CHEM 437 Chp 1

What drives the chemistry of life?

The biomolecules

What is life?

Self-sustaining system of chemical reactions driven by biomolecules.

Biomolecules

Carbon-based compounds containing H, N, and O (which make up over 99% of the atoms in the human body).

What properties of H, O, C, and N make these atoms so appropriate to the chemistry of life?

Their ability to form very strong covalent bonds by electron-pair sharing.

What is the build-up of biomolecules into a unit of life?

Precursors → metabolites → macromolecules and membranes → organelles → cell.

Prokaryotic

A single plasma membrane, no nucleus or organelles. Ex: bacteria, archaea

Eukaryotic

Much larger, membrane-bound organelles. Ex: animals, humans, plants.

What are the general properties of living systems?

• Complex and well organized

• Biological structures in an organism serve functional roles

• There is a flow of energy through living system

• Can self-replicate

How are the properties of biomolecules suitable for living systems?

• Biomolecules and their building blocks have a “sense” or directionality.

  • Ex: amino acids being built from N’ to C’.

• They contain information

  • Ex: DNA → mRNA → protein

• Have a characteristic 3-D architecture that determines their function

  • Allow them to specifically interact with other biomolecules

• Weak forces maintain biological structures and determine biomolecular interactions

Van der Waals Forces

Induced electrical interaction between approaching atoms/molecules.

Hydrogen Bonds

From between a hydrogen covalently linked to an electronegative atom and another electronegative atom.

Ionic Interactions

Interactions between opposite charges.

Hydrophobic Interactions

Result from a tendency to exclude non-polar group from water.

What is the catch of using weak chemical forces to mediate biomolecular recognition?

The weak chemical forces restrict organisms to a narrow range of environmental conditions (pH, temperature).