A three dimensional code for solving the set of Maxwell equations with the finite-difference time-domain method is developed to simulate the propagation and scattering of light in biological cells for realistic conditions. The numerical techniques employed in this code include the Yee algorithm, the absorbing boundary conditions, the total-field/scattered-field formulation, the discrete Fourier transformation and the near-to-far field transform with the equivalent electric and magnetic currents. The code is capable of simulating light scattering from cells with complex internal nanostructures at all angles. The effects of cellular nanostructure on the scattered light are studied. It is shown that changes in cellular nanostructures could cause significant changes in the scattered light at particular angles.