Final answer:
Option (b), The statement is false as ligand binding induces changes in the receptor that facilitate a signaling cascade rather than allowing the ligand itself to pass through the cell membrane.
Step-by-step explanation:
The statement that binding of a ligand to a membrane receptor allows the messenger to pass through the cell is false. When a ligand binds to a membrane receptor, it induces a conformational change in the receptor that affects the receptor's intracellular domain but does not allow the ligand itself to pass through the cell. Instead, this conformational change typically initiates a signaling cascade inside the cell, which can lead to various cellular responses without the ligand entering the cell.
Membrane receptors are involved with hydrophilic ligands and facilitate indirect actions such as activating enzymes or second messengers, whereas internal receptors can bind to hydrophobic ligands and then move into the nucleus to directly initiate transcription and the making of a functional protein.