Biomolecules

• The core biomolecules are carbohydrates, proteins, nucleic acids, and lipids
• Carbs, proteins, and nucleic acids are polymers
• A polymers is a chain of identical, covalently bonded molecules called monomers
• Monomers bond through condensation reactions in which a small molecule is lost
• A dehydration reaction occurs when a condensation reaction involves the loss of a water molecule
• Hydrolysis is the reverse of dehydration
• Carbohydrates can be monosaccharides, disaccharides, or polysaccharides
• Monosaccharides include glucose and fructose
• Disaccharides include sucrose, maltose, and lactose
• Polysaccharides include glycogen, starch, and cellulose
• Monosaccharides are of the formula (CH2O)n and typically have a carbon skeleton of 3,5, or 6 carbons. They have carbonyl and alcohol functional groups. They are hydrophilic
• Monosaccharides form rings to be more stable
• Glycosidic linkage is when a covalent bond links 2 monosaccharides into a disaccharide by dehydration reaction
• Polysaccharides are used for food storage (eg. glycogen, starch) and plant structure (eg. cellulose)
• Starch is made up of alpha glucose and cellulose is made up of beta glucose
• Lipids contain carbon and hydrogen. They are hydrophobic and include fats, phospholipids, and steroids
• Fats can be used for energy storage & insulation
• The structure of fats is a glycerol head and fatty acid arms with ester linkage
• Water cannot bond with fatty acids
• Saturated fats have no double bonds and are solid at room temperature
• Unsaturated fats have one or more double bonds and are liquid at room temperature
• Phospholipids have a hydrophilic head and 2 fatty acid chains. They self assemble into bilayers, a major component of cell membranes
• Steroids are made up of 4 rings with various functional groups and are hydrophobic
• Cholesterol is a steroid which increases fluidity of membranes and is a precursor for synthesis of other steroids