Question

Part 1 Imagine two cells. One is 10 microns long on each side and the other is 5 microns long on each side. Let’s say the job of these cells is to pick-up and transport oxygen to other parts of the body. Imagine the red dots represent oxygen molecules Which of the two cells will fill up with oxygen first? * 1 point The larger cell The smaller cell Both cells will fill up with oxygen in the same amount of time Which cell has a greater volume and can therefore hold more oxygen? * 1 point The larger cell The smaller cell They both can hold the same amount of oxygen Calculate the volumes of each cell to be certain. Volume = side x side x side The larger cell can hold ______ cubic microns of oxygen. * 1 point Your answer The smaller cell can hold ______ cubic microns of oxygen. * 1 point Your answer What can the smaller cell do in order to hold more oxygen? * 1 point Shrink to a smaller volume Do nothing but feel sorry for itself :( Make copies of itself Now imagine that there are 8 identical copies of the smaller cell Which cells will fill up with oxygen first? * 1 point The larger cells Both the smaller cells and the larger cell will fill up with oxygen in the same amount of time The smaller cells. Is the one large cell able to hold more oxygen than the group of 8 cells? * 1 point Yes, the larger cell can hold more oxygen. No, the larger cell can hold less oxygen. No, the larger cell can hold the same amount of oxygen as the 8 smaller cells can hold together. Calculate the volume of each to be certain. Again, the larger cell can hold ______ cubic microns of oxygen. * 0 points Your answer All together, the 8 small cells can hold ____ cubic microns of oxygen. * 1 point Your answer If they both can hold the same amount of oxygen, why is better to have 8 small cells than 1 large cell? * 1 point Together, the smaller cells have LESS surface area and they can therefore fill up with oxygen faster. It's not. The larger cell is better because it fills up with oxygen faster. Together, the smaller cells have MORE surface area and they can therefore fill up with oxygen faster.

Answer 1

The speed of filling up with oxygen ( or any other gas, that is) is called the rate of diffusion. It depends on the temperature, distance and cell surface. Since from the diagram we can assume that the temperature and the distance between cell and oxygen is the same for both cells, then the only factor that affects the rate of diffusion is the cell's surface. Since the cells here are presented as cubes, the surface of the cube is 6 • a^2. So, the surface of the larger cell is 6 • 10^2, which is 600, and the second cell is 6 • 5^2, which is 150. That means that the larger cell will fill up with oxygen faster.

Regarding the amount of oxygen the cells can store, we need to calculate the volume of each cell. They are cubes, so the volume is a • a • a. So, the larger cell has a volume of 10 • 10 • 10, which is 1000 cubic microns, and the smaller one 5 • 5 • 5, which is 125 cubic microns.

The ability of smaller cells is to divide faster than the big ones, which is, let's say, a sort of compensatory mechanism for their lack of size. So, in order to hold more oxygen, smaller cells divide.

In the situation where we have 1 large and 8 smaller cells, to determine which will fill with oxygen faster, again we need to determine their surfaces. We already calculated large cell's surface, which is 600 square microns. The surface of one small cell was also calculated, and it is 150 square microns. If we have 8 cells, their surface is 8 • 150, which is 1200. That means that 8 smaller cells have a greater rate of diffusion.

Regarding their volume, we already calculated that a large cell's volume was 1000 cubic microns, and one small cell had a volume of 125. That means that 8 small cells will have a volume of 8 • 125, which is 1000 cubic microns. That means that one large and eight small cells have the same volume.

Finally, since 1 large and 8 small cells have the same volume, but smaller cells have the greater surface ( as calculated before), that is the reason why it is better to have more smaller than one large cell.