Factors that Influence Diffusion | Biology for GCSE/IGCSE - Year 11 PDF Download

Factors that Influence Diffusion

Surface area to volume ratio

• The size of a cell or structure impacts its surface area to volume ratio. A larger cell has a smaller ratio, which in turn slows down the movement of substances across its surface.
• Cells specialized for diffusion often exhibit increased surface area adaptations. For instance, root hair cells in plants, responsible for water and mineral ion absorption, and cells lining the ileum in animals, involved in absorbing digested products, showcase enhanced surface areas to facilitate efficient diffusion processes.

Distance

• Transport speed is enhanced when molecules have shorter distances to travel.
• For instance, blood capillaries and alveoli possess single-cell thick walls to optimize diffusion rates.

Temperature

• Elevated temperatures accelerate molecular movement by increasing energy levels.
• This leads to heightened collisions with cell membranes, thereby expediting transport.

Concentration Gradient

• Greater disparities in concentration across a membrane result in faster movement.
• Higher concentrations prompt more frequent collisions with the membrane, facilitating swifter transport.