Question

The process by which specific materials can be moved across a plasma membrane with the help of transport protein is

• A. Concentration gradient
• B. Active transport
• C. Osmosis
• D. Facilitated transport
• E. Phagocytosis

Answer 1

The correct option is D Facilitated transport

Concentration gradient refers to the difference in the concentration of substances on either side of compartments. Active transport is the uphill movement of substances and requires ATP-powered pumps. Osmosis is the movement of the solvent through a semipermeable membrane down the concentration gradient. Transport hydrophilic small molecules down their concentration gradient is carried out by specific channel proteins and is termed as facilitated diffusion. Phagocytosis is mediated by outgrowth of the cell membrane and does not require any channel proteins. Thus, the correct answer is D.