According to Jeffrey Bada, director of the NASA Specialized Center of Research and Training (NSCORT) in Exobiology at Scripps Institution for Oceanography, a paper (SURVIVABILITY OF SMALL BIOMOLECULES DURING EXTRATERRESTRIAL DELIVERY: SIMULATION EXPERIMENTS ON AMINO ACID PYROLYSIS, Basiuk and Douda, Planetary Space Science 47:577- 584, 1999), found that most meteorites would simply get too hot and would destroy most amino acids and organic material during entry to the earth's atmosphere. In this paper, the only possible way to get significant organic material to earth was through interplanetary dust particles (IDPs). Bada himself later heated IDP's and found that during entry they can easily heat up to 1200 C, easily hot enough to destroy most organic material. Apparently the only amino acid that ever remained during Bada's realistic simulations was glycine. Bada called this "bad news" if you are interested in originating life based upon material from outer-space. (See a report on Bada's talk at UCSD on June 10, 2003 at http://www.arn.org/docs2/news/ucsdoriginoflife062003.htm.)
http://www.arn.org/docs2/news/ucsdoriginoflife062003.htm.)