“Assembling” I take to mean, “one atom at a time.” Given a machine that can maneuver individual atoms and bond them to each other one at a time, and given that your machine is so fast that it adds one billion atoms to the target every second, 6 billion nucleodites (the human genome) would take 6 times N seconds, where N is the average number of atoms in a nucleotide, including the sugars etc. that link it to the central double helix.
Cells being vast with respect to the nucleus inside them, we’re looking at somewhere between all day and all week to make one cell. While the nucleus is very complex, the cell’s simpler but more massive parts also have to be handled that same old slow billion atoms per second.
Your mission, should you choose to accept it, will be to make the machine that plants a new atom every nanosecond (one billion atoms per second) and can hold the vulnerable cell it’s working on in a benign environment (can’t let it dry out!) – –
Call me when you have that working.
Oh, and Another Thing 