Question

The movement of dye through an agar gel is an example of:

a. simple diffusion
b. osmosis
c. facilitated diffusion
d. active transport

Answer 1

The movement of dye through an agar gel is an example of simple diffusion, which is a type of passive transport that doesn't require energy. Ion pumps and phagocytosis, by contrast, are forms of active transport, requiring energy to move substances against their concentration gradient.

Step-by-step explanation:

The movement of dye through an agar gel is an example of simple diffusion. This process occurs when molecules move from an area of high concentration to an area of low concentration directly across the membrane without the need for energy or the assistance of carrier proteins or channels. Simple diffusion is a passive transport mechanism that involves molecules like gases (e.g. O2, CO2) moving down their concentration gradient.

In the case of ion pumps and phagocytosis, these are examples of active transport. Ion pumps move ions against their concentration gradient using energy, typically in the form of ATP. Phagocytosis is a form of endocytosis where the cell engulfs large particles or cells, also requiring energy. Hence, neither ion pumps nor phagocytosis are passive processes; instead, they are active because they require an input of energy.

The final answer to your question on the movement of dye through the agar gel is:

• a. simple diffusion