Introduction
Biochemistry is the study of the molecules and chemical reactions of life.
Major players:
Friedrich Wohler- synthesized urea, an organic compound, by heating an inorganic compound, ammonium nitrate. Showed for the first time that an organic ("living") compound can be synthesized from an inorganic ("non-living") compound.
Eduard Buchner- identification of enzymes as the catalysts of biological reactions. Showed that extracts of yeast cells could catalyze the fermentation of sugar to alcohol and carbon dioxide.
Emil Fischer- during catalysis an enzyme and its substrate (reactant) combine to form an intermediate compound. Only a molecule with suitable structure can serve as a substrate for a given enzyme....specificity.
James D. Watson/Francis H.C. Crick- three-dimentional structure of DNA
Chemistry of Life
Elements found in the human body:
| ELEMENT |
Abundance in Body(% of dry weight) |
Biomolecular Examples |
|
Carbon (C) Oxygen (O) Hydrogen (H) |
50.0 20.0 10.0 |
Proteins, Carbohydrates, DNA/RNA, Lipids, Heme |
| Nitrogen (N) | 8.0 | Protein, DNA/RNA, Heme |
| Calcium (Ca) | 4.0 | Bone |
| Phosphorus (P) | 2.5 | Bone, Lipids, DNA/RNA |
| Potassium (K) | 1.0 | Electrolyte |
| Sulfur (S) | 0.8 | Proteins |
| Sodium (Na) | 0.4 | Electrolyte |
| Chloride (Cl-) | 0.4 | Electrolyte |
| Magnesium (Mg) | 0.1 | DNA/RNA, Proteins |
| Iron (Fe) | 0.01 | Proteins, Heme |
Three most abundant and important are Carbon (C), Oxygen (O) and Hydrogen (H)
They comprise the majority of atoms in the FOUR classes of molecules found in the human body:
1. proteins
2. carbohydrates
3. nucleic acids (DNA and RNA)
4. lipids (including fat)
| Class of Molecule | Composition | Role in Human Body |
| Lipids | C, H, O (N, P) | Membrane Structure, Fuel, Fuel Storage |
| Carbohydrates (CHO's) | C, H, O (N) | Fuel, Fuel Storage, Cell-Cell Recognition |
| Proteins | C, H, O, N (S) | Enzymes, Tissue Structure, Fuel |
| Nucleic Acids (DNA, RNA) | C, H, O, N, P | Genetic Information Storage and Transfer |
Also important...
Nitrogen-proteins and nucleic acids
Phosphorus-nucleic acids
Calcium, Phosphorus-skeleton
Sodium, Potassium, Chloride-body fluids (electrolytes)
Magnesium-DNA and RNA
Iron-heme(participates in binding oxygen)
Covalent Bonds: A Review....
Covalent bonds are the main structural framework of proteins, carbohydrates, lipids, nucleic acids.
Oxygen has a high attraction for electrons to complete its outer shell.
i.e. oxygen is more elecronegative than than hydrogen. Result: oxygen will posses a partial negative charge while hydrogen becomes partially positive.---POLAR
Ionic Bonds: A review.....
Extreme differences in electronegativity between elements leads to ionic bonds.
Ions can actually drift apart especially in a polar solvent such as water.
In biological systems where water is the solvent Na and Cl nearly always exist as separate ions.
Water:
Most important biological molecule.
Important feature: Hydrogen Bonding Ability
The ability of water to hydrogen bond:
1. gives water great cohesion and resistance to vaporization.
2. allows for solvation of biomolecules.
Hydrophobic:
"water fearing", i.e. long-chain hydrocarbon
Hydrophilic:
"water loving", i.e. ionic, polar compounds
Amphiphilic:
both "water fearing" and "water loving"
Molecules which contain both a "hydrophilic" and "hydrophobic" region, i.e.
"A Fatty Acid"
Review of functional groups important in the study of biochemistry:
The Cell
The basic unit of life...
Every organism is composed of either a single cell or many cells.
There are two major classes of cells:
Eukaryotic- complex internal structure, including a prominent nucleus.
Prokaryotic- are less complex and much smaller.
Prokaryotic Cells:
Usually single celled organisms, such as bacteria.
E. coli-
1. lacks a nucleus, a large DNA molecule packed in the nucleoid region.
2. Cell-wall-made of a network of covalently linked carbohydrate and peptide chains.
Eukaryotic Cells:
Include plants, animals, fungi.
The Nucleus: Control center of the cell, containing 95% of its DNA.
DNA replication and transcription of DNA into RNA.
Endoplasmic Reticulum (ER):
Aqueous region enclosed w/in the ER is the lumen.
Protein synthesis/export.
Many enzyme systems involved in the metabolism of lipids.
Golgi Apparatus: Protein modification/sorting/packaging/transport.
Mitochondria: Central role in energy transduction.
Oxidative energy metabolism.
Chloroplasts: Sites of photosynthesis in plants and algae.
Mitochondrial Matrix: The inner mitochondrial membrane and the matrix contain many of the enzymes involved in aerobic energy metabolism.
Sites of Biochemical Processes in the Cell:
Just for interest, other elements important in biochemistry:
© Dr. Noel Sturm 2014