In article , Dr. Rev. Chuck, M.D.
P.A. writes

Not impossible, since chlorophyll and hemoglobin differ only in the metal
at their center.

Chlorophyll and heme differ in the metal at their centre (magnesium
versus iron). They also differ otherwise - see

http://www.chm.bris.ac.uk/motm/chlor...orophyll_h.htm
http://omlc.ogi.edu/spectra/hemoglobin/hemestruct/

Note that there are (at least) five different chlorophylls.

Hemoglobin is a large protein with attached to a heme. It is not the
only such protein - others include catalase, cytochrome C, cytochrome
c554, ferritin, and hemopexin. Google is your friend.
--
Stewart Robert Hinsley