erupt bailiwick to leger symmetry and the Relation to the Rate of Diffusion
Aim and Background
This is an prove to examine how the bug out knowledge base / record book Ratio affects the number of dispersal and how this relates to the size and shape of living organisms.
The surface landing field to volume ratio in living organisms is actually important. Nutrients and oxygen privation to deal through the cell membrane and into the cells. intimately cells are no seven-day than 1mm in diameter because down(p) cells en fitting nutrients and oxygen to sink in into the cell quickly and accommodate waste to diffuse out of the cell quickly. If the cells were any medium-large than this and because it would take too long for the nutrients and oxygen to diffuse into the cell so the cell would probably not survive.
Single celled organisms cigaret survive as they own a large abundant surface study to allow all the oxygen and nutrients they impoverishment to diffuse through. Larger multi-celled organisms need organs to respire such(prenominal) as lungs or gills.
Method
The reason I chose to do this crabbed experiment is because I ground it very interesting and as well because the aim, method, results- basically the whole experiment would be easily unsounded by the average person who knew nothing or so heighten Area/Volume Ratio. The variable being try outed in this experiment is the invest of diffusion in similarity to the size of the gelatin cube. Another experiment one could do to watch the surface area to volume ratio is to construct a set of cubes out of construction paper- 1 x 1, 2 x 2, 3 x 3 and 4 x 4 (cm).Then use this pattern to determine the surface area- L x W x 6 and compare it with the volumes. The formula to determine volumes of cubes is L x W x H. Although that subject of experiment will show no insight into SA/V ratio in relation to the rate of diffusion.
        Equipment
1. Â Â Â Â Â Â Â Â Agar-phenolphthalein - sodium hydrated oxide jelly
2. Â Â Â Â Â Â Â Â O.1 M hydrochloric pane of glass
3. Â Â Â Â Â Â Â Â Ruler (cm and mm)
4. Â Â Â Â Â Â Â Â Razor blade
5. Â Â Â Â Â Â Â Â Paper towel
6. Â Â Â Â Â Â Â Â Beaker
Method
1. A parry of gelatin which has been dyed with phenolphthalein should be cut into blocks of the following sizes (mm).
5 x 5 x 5
10 x 10 x 10
15 x 15 x 15
20 x 20 x 20
30 x 30 x 30
20 x 5 x 5
Phenolphthalein is an cutting/alkali indicator dye. In the alkali conditions of the gelatin it is red ink or purple but when it detects exposed to battery-acid it turns more or less colorless.
Gelatin is use for these tests because it is permeable which means it acts like a cell. It is liberal to cut into the required sizes and the hydrochloric acid can diffuse at an even rate through it.
2. A small beaker was fill with about 400ml of 0.1 molar Hydrochloric acid. This is a sufficient measuring of acid to assure that all the block sizes are fully cover in acid when dropped into the beaker.
3. One of the blocks is dropped into this beaker, left for 10 minutes, then removed, dried, and cut in two to measure the depth of penetration. This test should be repeated for all the sizes of blocks three times to ensure an accurate test. Fresh acid should be used for from severally one block to make sure that this does not affect the experiments results.
4. The Surface Area/Volume Ratio and an average of the results can then be worked out. A interpret of Surface Area to Volume Ratio can then be plotted on with percentages left colored and uncolored . From this graph we will be able to see how surface area affects the rate of diffusion of materials into the cubes.
Results
        I carried out the above experiment and these results were obtained.
Dimensions (mm)         Surface Area         Volume (V) (mm)         Surface Area / Volume Ratio         shew 1         Test 2         Test 3
5 x 5 x 5         150         125         1.2:1         1mm         1mm         1mm
10 x 10 x 10         600         1,000         0.6:1         1mm         1mm         1mm
20 x 20 x 20         2,400         8,000         0.3:1         1mm         1mm         1mm
30 x 30 x 30         5,400         27,000         0.2:1         1mm         1mm         1mm
The Surface Area to Volume Ratio is calculated by
SA = cm
From these results I was able to make a graph of the volume quieten drab along with the percentages left coloured and uncoloured.
Dimensions (mm)         Volume left coloured 3(mm )         Percentage coloured compared to genuine volume         Percentage penetratedby the acid
5 x 5 x 5         3mm         60%         40%
10 x 10 x 10         8mm         80%         20%
20 x 20 x 20         18mm         90%         10%
30 x 30 x 30         28mm         93.3%         6.7%
        Length of side not penetrated = (s - 2x)
                                3
Volume left coloured (Vc) = (s - 2x)
Percentage still coloured (C%) = Vc x 100
                        V         1
Percentage of cube penetrated = 100 - C%
Interpretation
In all the blocks of gelatin the rate of penetration of the hydrochloric acid from each side would subscribe been the same but all the cubes have different percentages still coloured because they are different sizes. As the blocks get bigger the hydrochloric acid to diffuses smaller percentages of the cubes. It would take longer to totally diffuse the largest cube even though the rate of diffusion is the same for all the cubes.
As the volume of the blocks goes up the Surface Area/Volume ratio goes down. The larger blocks have a smaller surface area than the smaller blocks. The smallest block has 1.2mm form of surface area for every 1mm cubed of volume. The largest block only has 0.2mm square of surface area for each 1mm cubed of volume. This means that the hydrochloric acid is able to diffuse the smallest block much faster than the largest block.
When the Surface Area/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.
The single error or limitation I encountered was the impossiblity to precisely measure the size of gelatin block. I measurable the sizes to the nearest mm so the sizes of block that I used should be correct to the nearest mm.
Discussion
It is important that cells have a large surface area to volume ratio so that they can get enough nutrients into the cell.
Single celled organisms have a large surface area to volume ratio because they are so small. They are able to get all the oxygen and nutrients they need by diffusion through the cell membrane.
Here is a plot of a standard leaf:
Their are openings within a leaf called stomata. These allow for the gases to flow in and out of the leaf. Leaves of plants have a large surface area, and the irregular-shaped, spongy cells increase the area even more meaning a larger amount of gas exchange. An example of surface area to volume ratio in a real world context would be something such as the example that was just explained.
Therefore, by increase the surface area the rate of diffusion will go up.
Appendices
(2002) Biology: The Surface Area to Volume Ratio of a Cell [Web document] hypertext transfer protocol://www.geocities.com/CapeCanaveral/Hall/1410/lab-B-24.html
This piece of information was a good start for the investigation of Surface Area to Volume Ratio investigation. Even though it has no mention about rate of diffusion in relation to SA/V ratios, its relevance to my investigation was crucial.
(2002) Encyclopedia Britannica: Biology- Surface Area to Volume Ratio
[CD-ROM]
I found this source of information to be very reliable. The Encyclopedia Britannica is a popular and credible way to gain information. It covers the whole picture of factors relating to SA/V ratios as well as the rate of diffusion. It was very appropriate for my investigation.
(2000) Sizes of Organisms: Surface area to Volume ratio [Web document] http://www.tiem.utk.edu/~mbeals/area_volume.html
This document had an in depth discussion about the relation between Surface Area and Volume Ratios. It used batch of examples to get the point across more clearly. It also touched(p) on Surface Area to Volume Ratios of spheres.
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