Final answer:
The statement is False. Membrane proteins act as receptors and trigger signal transduction processes within the cell without physically moving from one membrane layer to another.
Step-by-step explanation:
The statement that proteins transmit signals from the outside of the cell to the cytoplasm by flip-flopping from the outer membrane monolayer to the inner monolayer is False. Proteins, specifically membrane proteins, transmit signals through a process known as signal transduction. These proteins are typically embedded in the cell's plasma membrane and function as receptors.
When a signaling molecule, such as a hormone or neurotransmitter, binds to a membrane protein receptor on the outside of a cell, it triggers a conformational change in the protein. This change then initiates a cascade of events inside the cell, leading to an appropriate cellular response. Importantly, membrane proteins do not move between the monolayers of the plasma membrane as part of this process. Instead, they remain in their respective locations and transmit signals by altering their shape or by interacting with other proteins or molecules.