Understatement. There are 50 trillion atoms in a cell, 50 trillion cells in a human body (give or take an order of magnitude or two for definitions and caveats). Furthermore, big swaths of chemistry/biochemistry are inherently quantum mechanical (classical mech + E&M doesn't explain why molecules snap into little geometric shapes, let alone how those shapes interact) which has god-awful asymptotic complexity on account of the "present state" of the system (wavefunction) being a probability for each possible configuration of the system rather than a description of a single configuration.

A purpose-built silicon supercomputer will struggle to simulate a single small protein using classical-mechanics approximations for a millisecond (and there are millions of those per cell and trillions of cells per body). There's a lot of room for improvement.