So that they don't explode.
AKA with a thing called osmosis (transportation of water through cells.)
Answer:
Theory is not definite, while Law is.
Explanation:
A Theory is an idea or set of ideas that has proven itself many times, but has certain loopholes that prevent absolute certainty. Meanwhile, a Law is a Theory without loopholes.
The part of the amino acid that gives the molecule its unique or characteristic chemical properties would be the R-group. Every amino acid has three main groups in it namely the amino group, carboxyl group and the R group. "R" represents different organic chain that is specific to a certain amino acid which gives different properties of the molecule.