MOVING FROM ECOLOGY TO BIOCHEMISTRY

BIOCHEMISTRY LEVELS OF ORGANIZATION

Organisms

Organ Systems

Organs Tissues

Cells Molecules Atoms

Subatomic

Particles

BIOLOGICAL BONDS (CONCEPT 2.3)

• TYPES OF BONDS & INTERACTIONS

• COVALENT BONDS

• IONIC BONDS

• HYDROGEN BONDS

• HYDROPHOBIC & HYDROPHILIC INTERACTIONS

• VAN DER WAALS INTERACTIONS

COVALENT BONDS

• VALENCE ELECTRONS ARE SHARED BY TWO ATOMS

• THERE ARE TWO TYPES

• POLAR – SHARED UNEQUALLY

• NONPOLAR – SHARED

EQUALLY (O=O, H-H)

IONIC BONDS

• SOME ATOMS ATTRACT VALENCE ELECTRONS SO UNEQUALLY THAT THE MORE ELECTRONEGATIVE ATOM STEALS THE ELECTRON AWAY FROM THE LESS ELECTRONEGATIVE

HYDROGEN BONDS

• THE SLIGHTLY POSITIVE

HYDROGEN ATOM OF A POLAR

MOLECULE IS ATTRACTED TO

THE SLIGHTLY NEGATIVE ATOM

OF ANOTHER MOLECULE

• WATER IS POLAR

  

HYDROPHOBIC & HYDROPHILIC INTERACTIONS

• HYDROPHOBIC – “WATER-FEARING”

• NONPOLAR MOLECULES

• NO AFFINITY FOR WATER

• HYDROPHILIC – “WATER-LOVING”

• POLAR MOLECULES

• HAVE AN AFFINITY FOR WATER

VAN DER WAALS INTERACTIONS

• WEAK INTERACTIONS BETWEEN MOLECULES OR PARTS OF MOLECULES THAT RESULT FROM TRANSIENT LOCAL PARTIAL CHARGES

• WAIT. WHAT?

• VIDEO