Farnesyl pyrophosphate is an intermediate in isoprenoid biosynthesis formed by joining geranyl pyrophosphate with isopentenyl pyrophosphate (IPP), as follows:

Geranyl Pyrophosphate + IPP <=> Farnesyl Pyrophosphate + PPi (Figure 19.20)

In cholesterol biosynthesis, farnesyl pyrophosphate is converted to presqualene pyrophosphate, as follows:

2 Farnesyl Pyrophosphate <=> Presqualene Pyrophosphate + PPi (Figure 19.21)