Question

Small molecules like O₂ and CO₂ can diffuse through the cell membrane, traveling from _____ to _______ concentration.

a) High, low
b) Low, high
c) Equal, unequal
d) Inside, outside

Answer 1

O₂ and CO₂ diffuse through cell membranes from high to low concentration areas via simple diffusion, a type of passive transport.

Step-by-step explanation:

Small molecules like O₂ and CO₂ can diffuse through the cell membrane, traveling from an area of high to low concentration. This process is known as passive transport, specifically a type of passive transport called simple diffusion. O₂ typically diffuses into cells where its concentration is lower, while CO₂ diffuses out of cells where its concentration is higher. Neither process requires energy, as both molecules move down their concentration gradients across the lipid bilayer of the cell membrane without the assistance of transport proteins.