What determines the efficiency of diffusion throughout the model ‘cell’?

Hypothesis: The diffusion is affected by size and volume. The further to the cubes centre and the wider the surface means that the material has a wider and longer space to travel until it reaches full diffusion, therefore rendering the larger surface area and volume cube to be less efficient.

DATA TABLE:                                                                                                                                      

Cube Size	Total cube volume (cm3)	Total volume that was not pink (cm3)	Volume of the diffused cube (total volume – volume that was not pink)	Percent Diffusion	Surface area of cube (cm2)	Surface area to volume ratio
1cm	1cm3	0.25cm3	0.75cm3	75%	6cm2	6:1
2cm	8cm3	6.84cm3	1.16cm3	14.5%	24cm2	3:1
3cm	18cm3	14.3cm3	3.75cm3	20.8%	42cm2	7:3

Question

1. In terms of maximizing diffusion, what was the most effective size cube that you tested?
   • The most effective cube was the 1cm cube, in the photo it shows that the 1cm cube was more pink than the others, and had very littel agar left that was not pink. The hydroxide solution was able to extend through this cube and cover more of it’s area.
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 important factors that helpedmaximize diffusion was surface area and volume. The smaller cube had more hydroxide in it because it had less space that need hydroxide solution absorbed. The smaller cube has a smaller surface area to a lower volume, meaning that the diffusion reaches a wider surface and has less material to penetrate. This helps for it to be the highest diffused percentage.
3. If a large surface area is helpful to cells, why do cells not grow to be very large?
   • Cells need to have materials reach the center. High surface area is helpful, but must also have a low volume. Cells don’t want to get too big to lose their low volume aspect. The large surface area allows more areas for materials to enter and the low volume helps them travel a short period until the centre. Therefore, a smaller cell comes with a larger surface area compared to volume which helps cell functions such as materials entering the cell.
4. You have three cubes, A, B, and C. They have surface to volume ratios 6:1, 3:1, 7:3 respectively. Which of these cubes is going to be the most effective at maximizing diffusion, how do you know this?
   • Cube C (1cm cube, 6:1 ratio). It has a large surface area and a low volume, the surface area is much larger than its volume. This ratio helps gain the highest percent diffusion.
5. How does your body adapt surface area-to-volume ratios to help exchange gases?
   • Our body adapts the ratio for Alevoli, an air-filled sac inside our lungs. They need a large surface area to volume ratio to allow gas exchnage to occur more rapidly in our body.
6. Why can’t certain cells, like bacteria, get to be the size of small fish?
   • Bacteria are single-celled organisms. As seen in the lab, cells prefer to have a lower volume, so being the size of a fish would not help the functions of the cell. A cell needs to stay small for diffusion of materials.
7. What are the advantages of large organisms being multicellular?
   • Our body has multiple cells with unique purposes. This helps human functions, so having organisms be created of one cell would render us useless. In addition, multi-cellular organisms have the advantage and the ability that they can grow, whereas a single-celled organisms like bacertia can only reproduce and multiple itself. Multi-ceullar organisms have the potential to do so much more than a single-celled organism because of the help of many cells.