The most effective size cube that we tested was the 1x1x1 cube. When we cut it open, you can see that the whole cube turned pink, unlike the other two that are still slightly foggy. This cube was the most effective at maximizing diffusion because it had the greatest SA:V ratio. Some important factors that affect how materials diffuse are the thickness of the material, the concentration, the temperature and more.
The cells can’t grow too large because even if a large surface area is good, the volume size would increase and the SA:V ratio would become smaller. This makes it harder for cell diffusion to be efficient.
Out of the three cubes, A, B and C, the third cube (C) would be the most effective at maximizing diffusion because if they are all ratios to one (3:1, 2.5:1 and 4:1) cube C would have the most surface area to volume ratio. It has the most surface area for materials to pass through, while still having less of its’ “insides” be affected.
Our bodies adapt SA:V ratios to help exchange gases by having cells that are shaped differently to maximize diffusion and organelles that have a lot of folds in their membranes.
Bacteria can’t get as big as fish because, similar to one of the previous questions, the cells will start to grow and the SA:V ratio would become smaller making cell diffusion harder. The cells would function less efficiently and they would start to divide.
One advantage of large organisms being multi cellular is that the rate of diffusion is higher for them, allowing the organism to function more efficiently altogether. Another advantage is that they have a longer lifespan. Since they have multiple cells, once a cell dies it’s not like the whole organism also dies.
