Question

what is the driving force behind diffusion?
water pressure
concentration gradient
external energy
protein pump
question 2
1 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?
osmosis
active transport
diffusion
facilitated diffusion

Explanation:

• For the first question: Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. The concentration gradient (difference in concentration) drives this movement. Water pressure is related to osmosis (a type of diffusion for water). External energy is not involved in simple diffusion (it is passive). Protein pumps are for active transport (which requires energy and is against the concentration gradient).
• For the second question: When food coloring spreads in water, it is because of diffusion (movement from an area of higher color concentration - the drop - to areas of lower color concentration - the surrounding water). Osmosis is specifically for water movement. Active transport requires energy and is not the case here. Facilitated diffusion needs transport proteins (not relevant for food coloring in water as it can freely move without such proteins in this simple case).

Answer:

1. concentration gradient
2. diffusion