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.
Root nodules contain nitrogen fixing bacteria which help a plant to obtain nitrogen compounds, which are needed for the production of protein (and although plants do not contaâ¦in as much protein as animals do, they still need a certain amount of it). Making the world better, one answer at a time.