Here are the definitions and energy requirements for each type of transport:
Simple Diffusion
Definition: Simple diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration directly through the lipid bilayer of a cell membrane. This process occurs for small, nonpolar molecules (like oxygen and carbon dioxide) that can readily pass through the membrane without the need for assistance.
Energy Requirement: Does not require energy (passive transport).
Facilitated Diffusion
Definition: Facilitated diffusion is a type of passive transport where molecules move across the cell membrane through protein channels or carriers. This process occurs for larger or polar molecules (like glucose and ions) that cannot easily pass through the lipid bilayer.
Energy Requirement: Does not require energy (passive transport).
Osmosis
Definition: Osmosis is the diffusion of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. This process helps to balance solute concentrations on either side of the membrane.
Energy Requirement: Does not require energy (passive transport).
Active Transport
Definition: Active transport is the movement of molecules across a cell membrane from an area of lower concentration to an area of higher concentration using energy, typically in the form of ATP. This process is often mediated by specific transport proteins.
Energy Requirement: Requires energy (active transport).
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