Effect of surface area and volume on the rate of diffusion by Hana Jawz on Prezi
inside the cell. Unit = cm3. Cube size. Surface area. Volume. SA:V ratio Cells need to be small because they rely on diffusion for getting substances into time but the bigger cubes did not change colour on the inside as the NaOH hadn't. How Surface Area to Volume Ratio Affects The Rate Of Diffusion In I predict that as the Surface Area / Volume Ratio increases the time taken for the A larger block has a smaller amount of surface area in relation to it's size. Effect of surface area and volume on the rate of diffusion region of lower concentration or the change of concentration over a period of time.
The smallest block has 1.
The largest block only has 0. This means that the hydrochloric acid is able to diffuse to the centre of the smallest block much faster than the largest block. The acid took 48 minutes to diffuse to the centre of the largest block but only 1 minute in the smallest block. A living cell would not survive if it had to wait 48 minutes for oxygen to diffuse through it so living cells need to be very small.
When the surface area to volume ratio goes down it takes longer for the hydrochloric acid to diffuse into the cube but if the ratio goes up then the hydrochloric acid diffuses more quickly into the block of gelatin. Some shapes have a larger surface area to volume ratio so the shape of the object can have an effect on the rate of diffusion.
It is important that cells have a large surface area to volume ratio so that they can get enough nutrients into the cell. They can increase their surface area by flattening and becoming longer or by having a rough surface with lots of folds of cell membrane known as villi.
The cell membrane is made up of a lipid bi-layer with many proteins integrated into it. The concentration of oxygen in the cell is always lower than outside the cell which causes the oxygen to diffuse in. Gases will always dissolve from an area of high to low pressure. The concentration of carbon dioxide outside the cell is lower than the concentration in the cell so the carbon dioxide will always dissolve out of the cell.
Single celled organisms such as amoebas have a large surface area to volume ratio because they are so small.
Surface Area / Volume Ratio Biology Experiment
They are able to get all the oxygen and nutrients they need by diffusion through the cell membrane. Larger organisms such as mammals have a relatively small surface area compared to their volume so they need special systems such as the lungs in order to get enough oxygen.
Surface area to volume ratio is very important in lungs where a large amount of oxygen has to get into the lungs. The lungs have a very large surface area because they contain millions of sacs called alveoli which allow oxygen to diffuse into the bloodstream.
Relationship between SA:V and rate of diffusion - The Student Room
By having millions of these alveoli the lungs are able to cram a very large surface area into a small space. This surface area is sufficient for all the oxygen we need to diffuse through it and to let the carbon dioxide out. By increasing the surface area the rate of diffusion will go up.
Precautions a All the gelatin used should be taken from the same block to ensure that all the blocks are made up of the same materials. Limitations To help make this experiment more accurate, I repeated it three times for each block size and then used the average of all the results to plot a graph with a line of best fit.
I tried to keep all the variables except for the size of the gelatin blocks the same for all the experiments. For example, when length is doubled i. The increase in volume is always greater than the increase in surface area.
This is true for cubes, spheres, or any other object whose size is increased without changing its shape. For cubes smaller than this, surface area is greater relative to volume than it is in larger cubes where volume is greater relative to surface area. Sometimes a graph that shows how the relationship between two variables changes is more instructive.
For example, a graph of the ratio of surface area to volume,clearly illustrates that as the size of an object increases without changing shapethis ratio decreases. Mathematically, that tells us that the denominator volume increases faster relative to the numerator surface area as object size increases.
How does surface area to volume ratio affect the rate of diffusion?
Organisms exhibit a variety of modifications, both physiological and anatomical, to compensate for changes in the surface area to volume ratio associated with size differences. One example of this is the higher metabolic rates found in smaller homeothermic animals.
Because of their large surface area relative to volume, small animals lose heat at much higher rates than large animals, and therefore must produce more heat to offset the effects of thermal conductance. Another example is the variety of internal transport systems that have developed in plants and animals for actively moving materials throughout the organism, thus enabling them to circumvent the limits imposed by passive diffusion.