(Inserted above is my group’s datasheet for the agar cube lab. All our information for our lab is recorded above.)

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

The most effective size cube that we tested was the 1cm cube. This cube was the best at diffusion and the percent diffusion was 100% compared to the 2cm cube which has a percent diffusion of 81.25% and the 3cm cube with 70.37%.

( This is a photo of the agar cubes cut in half to see the diffusion after a 10 minute period.).

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

The 1cm cube was most effective at maximizing diffusion as it has the highest surface area ratio and the lowest volume ratio (6:1). The 6 represents the surface area and the 1 represents the volume. For successful diffusion, the ratio should have a high surface area and a low volume.  The important factors that affect how materials diffuse into cells or tissues that we touched on in this lab is the surface area to volume ratio; however, other factors may include temperature, concentration, density, and pressure.

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

A large surface area is helpful to cells, through this lab we could see that the more surface area cells and lower volume in the ratio are ideal for the most effective diffusion. Cells do not grow to be very large because if they increase in size, they increase volume which in turn will increase the SA: V ratio. This means that in reality, diffusion becomes harder and less effective if cells were to grow very large. Cells need to be small because they rely on diffusion for getting substances into and out of their cells.

4. You have three cubes, A, B, and C.  They have surface 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 this?

Cube C (4:1) will be most effective at maximizing diffusion as it has the highest Surface Area in the SA: V ratio.

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

Your body can adapt its ratios in a number of ways such as: folding the surface of the object/ cell membrane, being shaped differently to perform specific functions, or/and cells divide when they get to bid to restore/have a larger SAV ratio. Producing a high SAV ratio is very important as this allows us to have a good gas exchange rate; however, if our surface are drops, so does our rate of gas exchange.

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

Bacteria is unicellular and must be able to sustain itself, as opposed to a small fish that is multi-cellular and is composed of many different cells. Bacteria need to be able to diffuse efficiently as if it can not it will die. If the bacteria became the size of a small fish the surface area would grow but so would the volume and as a result, the diffusion is not as effective and the bacteria will die.

7. What are the advantages of large organisms being multicellular?

By being multicellular organisms, plants and animals have overcome the problems of small cell sizes. Each cell has a large SAVratio which is necessary as there are a lot of functions needed to be performed with their specialized systems and cells. These features include gas exchange organs (lungs) and circulatory system (blood) to speed up and aid the movement of materials into and out of the organism. Furthermore, by being multicellular the cells in large organisms can vary in size if necessary.