The gravitational force makes it harder for cellular biologies to construct their proteins. Remember that ribosomes need to carry amino acids to the protein chain in order to create more complex structures.
In the absence of a gravitational field, there are several things that could be affected. Will ribosomes be able to navigate effectively without some sort of 'down' reference? Will ribosomes be more efficient in their construction of proteins without the force of gravity working against their movement? These are surely just a few of the questions the researchers would hope to find out more about from an experiment such as this.
With regards to your comparison to the electromagnetic force, I cannot give an educated response. My understanding is that cellular life uses the electromagnetic force as a tool to assist in their construction of proteins and other energy-related processes. Essentially, this means they can make their job easier by taking advantage of the physics in a 'smart' way.