Carboxyl groups have an electronegative oxygen atom double bonded to a carbon atom. This carbon-oxygen bond is very polar and the fact that its a double bond increases the polarity of the bond.
PEA agar, also referred to as Phenylethyl Alcohol Agar is a medium  used by microbiologists to grow microorganisms. The ingredient that  supplies nitrogen is casein. Making the world better, one answer at a time.
How to Germinate Peas. Peas supply a wide variety of nutrients to your diet. Depending on the type--from sugar snap peas to dry peas to green garden peas-they provide high amounts of fiber, iron, protein, Vitamin C, lysine, tryptophan and carbohydrates.