is  still   very    important   for Test    Day success;    that    content is  found   in  Chapters    1,  2,  3,  6,  and 7

of  MCAT    Biochemistry    Review.

Introduction

Organic chemistry is the study of carbon-containing molecules. But as you’ve seen, carbon is not the
only element that plays a role in organic molecules; many of the functional groups we’ve explored
up until this point also include hydrogen and oxygen. Together, these three elements make up 93%
of the composition of the human body by weight. But other atoms also contribute to biomolecules:
nitrogen comprises 3.2% of body weight and phosphorus 1.0%.

In this chapter, we’ll take a look at some biologically important molecules that contain nitrogen and
phosphorus. In addition to the amides explored in the previous chapter, amino acids also contain
nitrogen. These building blocks of proteins are discussed in depth in Chapter 1 of MCAT Biochemistry
Review; in this chapter, we review their structure and focus on laboratory methods for synthesizing
amino acids. Finally, we turn our attention to phosphorus-containing molecules, which often are
used to transfer energy—or store genetic information.