A peptide unit is planar - how many atoms are in the same plane in a peptide unit, counting all C, H, O, and N? Biology A peptide unit is planar - how many atoms are in the same plane in a peptide unit, counting all C, H, O, and N? A. 2 B. 4 C. 5 D. 6 E. 8 Answer: D Share this Share on FacebookTweet on TwitterPlus on Google+