Download Review of Biological Chemistry

Review of Biological Chemistry
Biologically Important Elements
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphorus
All organic
compounds
Organic compounds
Terminal electron
acceptor;
Carbohydrates, lipids
Proteins
Protein tertiary
structure
Nucleic acids;
Phospholipids; ATP
Chemical Bonds
•
Covalent
– Sharing of electrons
– Strong bonds
– Multiple bonds
possible (especially
with carbon)
• Single
• Double
• Triple
•
Ionic
– Transfer of
electrons and
attraction of
resulting ions
– Relatively weak;
tend to dissociate
Hydrogen Bonds
•
•
•
Attraction between
portions of different
molecules with partial
charges
Water molecules
Important in the
structure of proteins
Macromolecules in Cells
•
•
•
•
•
Carbohydrates
Lipids
Proteins
Nucleic Acids
Note: Most of
the cell is water
Carbohydrates
•
•
•
•
Composed of carbon,
hydrogen and oxygen
General formula:
Cx(H2O)y
Polymers of simple
sugars such as glucose
Storage of energy and
structural compounds
Linkages Between Sugars: Alpha
Linkages Between Sugars: Beta
Lipids
•
•
•
•
Chemically diverse group of chemicals
Defined on the basis of hydrophobicity -lipids do not dissolve in water.
Include fatty acids, fats, and waxes
Major structural components of membranes
-- phospholipids
Phospholipids and Membranes
•
•
•
Lipid with attached
phosphate group
Hydrophilic head with
hydrophobic tail
When placed in water
orient with lipids on
inside and phosphates
facing the water -bilayer or membrane
Proteins
•
•
•
Function as enzymes and structural
components of cells/organisms
Polymer of amino acids
Multiple levels of molecular organization
– Primary structure
– Secondary
– Tertiary
– Quaternary
Amino Acids
•
Central carbon atom
with attached
– Amino group
– Carboxylic acid
group
– “R” substitution
group/side chain
– Hydrogen
Peptide Bonds
•
•
Two amino acids
become linked by a
hydrolytic reaction
between the amino
group on one and the
acid group on the
other.
Note: this leaves a free
amino and acid group
for additional bonds.
Levels of Protein Structure
•
•
Primary structure
– Linear sequence of amino acids
– Ultimately this determines all other levels
of structure
Secondary structure
– Folding of the amino acid chain into
repeating structures -- alpha helix and
pleated sheets
Secondary Structure
•
Tertiary structure
– Folding into a globular form due to
intramolecular interactions
• Hydrogen bonds
• Ionic interactions
• Sulfur bridges
• Hydrophobic interactions
Quaternary Structure
•
•
Some proteins are
made of multiple
protein chains which
associate
Example hemoglobin
Nucleic Acids
•
•
DNA
– Deoxyribonucleic acid
– Carries all the genetic information of the
organism
RNA
– Ribonucleic acid
– Transfer of information from DNA to
proteins
Components of Nucleic Acids
•
•
•
Phosphates
Sugar
– RNA: ribose
– DNA: deoxyribose
Bases
– Purines
– Pyrimidines