Neutron or radiation transport kernels in general have two factors, namely, the space transition part and the energy-angle transition part. Importance biasing schemes are obtained here for these two factors separately leading to zero variance estimation by Monte Carlo. These biasing schemes are different from the one obtained by straightforward extension of importance biasing of the transport kernel. New biasing schemes are obtained for collision, track-length, and expectation estimators. Using the moments equations developed by Amster and Djomehri and extended by Lux to treat nonanalog games it is shown that these new biasing schemes lead to zero variance in the Monte Carlo estimation of reaction rate type of quantities.