Question

what is the driving force behind diffusion?
concentration gradient
external energy
water pressure
protein pump
question 2
2 pts
if you place a drop of food coloring into a beaker of water, what process causes the color to eventually spread evenly throughout the water?
diffusion
facilitated diffusion
osmosis
active transport

Explanation:

• First question: Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. The concentration gradient (the difference in concentration between two areas) drives this movement. External energy is not required for simple diffusion (it is for active transport). Water pressure is related to osmosis (a special case of diffusion for water). Protein pumps are involved in active transport (using energy to move substances against a concentration gradient).
• Second question: When food coloring spreads in water, it is simple diffusion. Facilitated diffusion requires transport proteins (not needed here as food - coloring can move through the water without such assistance). Osmosis is specifically the diffusion of water. Active transport requires energy input, which is not the case for the spreading of food coloring in water.

Answer:

1. concentration gradient
2. diffusion