Choose the correct option:
$(1)$ The value of ${\psi _S}$ is always negative / positive.
$(2)$ Porins are a type of carbohydrates / proteins.

(A) $(1)$ The solute potential $({\psi _S})$ is always negative because the addition of solute particles to a solution decreases the free energy of water,thereby lowering the water potential.
$(2)$ Porins are transport proteins that form large pores in the outer membranes of plastids,mitochondria,and some bacteria,allowing molecules up to the size of small proteins to pass through.