Diffusion in Agar Cubes

In terms of maximizing diffusion, what was the most effective size cube that you tested?

In terms of maximizing diffusion, the 1 cm cube was the most effective. All three cubes soaked in the sodium hydroxide solution for ten minutes, but the 2 and 3 cm cubes did not change colour on the inside as the solution had not diffused in yet.

Why was that size most effective at maximizing diffusion? What are the important factors that affect how materials diffuse into cells or tissues?

That size was most effective at maximizing diffusion because it had the largest surface area to volume ratio. This, along with concentration, mass, membrane thickness, pressure, temperature, are important factors that affect how materials diffuse into cells or tissues.

If a large surface area is helpful to cells, why do cells not grow to be very large?

Although a large surface area is helpful to cells, they do not grow to be very large because small cells are more efficient at diffusion. When a cell grows, its surface area to volume ratio decreases. There is comparatively less cell membrane for the substances to diffuse through resulting in the centre of the cell not receiving the substances that it needs. Diffusion is less efficient, and cell processes slow down.

You have three cubes, A, B, and C. They have surface area to volume ratios of 3:1, 5:2, and 4:1 respectively. Which of these cubes is going to be the most effective at maximizing diffusion?How do you know that?

Cube C is going to be the most effective at maximizing diffusion because it has the largest surface area to volume ratio.

How does your body adapt surface area to volume ratios to help exchange gases?

Your body adapts surface area to volume ratios to help exchange gases by cell division, slowing down metabolism, having long and thin cells rather than round and fat cells, (nerve cells), and having folds in the cell membrane (microvilli of intestinal epithelial cells).

Why can’t certain cells, like bacteria, get to be the size of a small fish?

Certain cells, like bacteria, cannot get to be the size of a small fish because when they get too large, they must divide.

What are the advantages of large organisms being multicellular?

The advantages of large organisms being multicellular are overcoming the problems of small cell sizes. Each cell has a large surface area to volume ratio, and they have also evolved features such as gas exchange organs (lungs) and a circulatory system (blood) to speed up and aid the movement of materials in and out of the organism.