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.
In addition to being rich in protein, peas also contain a great variety of essential vitamins and minerals, especially thiamine, folate, niacin, phosphorous and zinc, which are vital to cell growth and development. Frozen peas are widely available and are very versatile cooking ingredients.