• With the exception of water, virtually all chemicals of life are CARBON based
• Molecules that contain Carbon are considered organic with some exceptions such as CO2
• Carbon has 4 valence electrons so it is oriented in a tetrahedron shape
Sketch→
• Carbon can form up to 4 covalent bonds and can form long chains, rings, and branched chain molecules
• Carbon acts as the backbone of biological molecules
• Molecules that only contain carbon and hydrogen are known as hydrocarbons→ because of their symmetrical shape, they are considered non-polar or hydrophobic
• Other elements such as oxygen, sulfur, phosphorus, and nitrogen may attach to the carbon backbone to form reactive “clusters of atoms” called functional groups
• These functional groups possess chemical properties that are passed on to the hydrocarbon chain that they are attached to. They are also considered much more reactive than the hydrocarbon chain they are attached to.
• Refer to Figure 4 on pg. 26 • The hydroxyl group (-OH) and the carboxyl group (-COOH) are polar which help to make sugars and alcohols highly soluble in water
• Amines (-NH2) found in amino acids are considered a weak base
• Those molecules that have a carboxyl group (weak acid) and an amine group (weak base) are known as Amino acids… the building blocks of proteins.
• The phosphate group is found in molecules such as ATP, the energy carrier molecule used in cellular respiration.
Biological Macromolecules
Macromolecule= large molecules sometimes composed of a large number of repeating units.
There are 4 macromolecules in living organisms:
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids
Macromolecule Subunit
Carbohydrate Simple sugar
Lipid Glycerol & fatty acids
Protein Amino acid
Nucleic Acids Nucleotide
All the above molecules are assembled and dissembled in the same way.
1. Anabolic Reactions→ construct large molecules from combining smaller subunits
Condensation