Diffusion and Selective Permeability in Biological Systems Quiz

Diffusion is the passive movement of molecules from regions of higher concentration to regions of lower concentration.

Selectively permeable membranes control the passage of certain substances while restricting others.

Color of molecules is not a factor affecting the rate of diffusion; factors like concentration gradient, temperature, and surface area do.

Endocytosis is the process by which cells take in substances by engulfing them into vesicles formed from the cell membrane.

Active transport requires energy input to move molecules against their concentration gradient, making it distinct from passive transport.

Facilitated diffusion is a form of passive transport where molecules move across the membrane through protein channels.

Osmosis is the diffusion of water across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

Small, nonpolar molecules like carbon dioxide diffuse most rapidly through lipid bilayers.

Active transport involves the movement of molecules against their concentration gradient, requiring energy usually in the form of ATP.

The size of the molecule primarily determines its ability to passively diffuse through a membrane.

Carrier proteins aid in the passive movement of molecules across the membrane, following their concentration gradient.

Passive transport involves the movement of molecules down their concentration gradient without the input of energy.

Receptor proteins on the cell membrane are responsible for recognizing and binding to specific molecules, initiating cellular responses.

Transmembrane proteins, such as ion channels, traverse the entire lipid bilayer, facilitating the movement of ions across the membrane.

Channel proteins create pores in the membrane, allowing ions to move through in response to gradients without requiring energy.