Discussion Of Lab Report Mic 125 Exercise 2 656b31

Discussion

Simple staining is a method that is used in microscopy to enhance the visualization of microscopic images. Stains and dyes are the two major chemicals that are usually used in simple staining to examine the structure and the morphology of the bacterial cell. In this experiment, methylene blue solution was used to stain the bacterial smears. The methylene blue solution is used to stain animal cells to make their nuclei more observable for viewing under the microscope. When observed the onion skin cell, the cells looked as on a brick-like structure and within the cells, small dots (the nuclei) can be seen. When the specimen was observed under microscope with total magnification 40x, there were about a hundred rows of rectangular cells, but as the total magnification were changed into another, the number of cells in the field of view decreased. When observed the onion skin cell at (400x) of total magnification, the nuclei of the cells looked clearer and larger and able to study the cell with more understanding compared to the first magnification. The organelles that was observed in this type of cell were the nucleus, the cytoplasm and the cell wall. Unlike the onion skin cells, the cheek cells were more spread out from each other and they all had a round shape. When observed the cheek cells at 40X total magnification, the cells were secluded and spread out. At 400X total magnification, the image viewed one cell at a time, due to the fact that the cells were separated from each other. The organelles that were visible in this type of cell were the nucleus, the cytoplasm and the cell membrane. Aside from the actual cells, the air bubbles could be observed within both the onion skin cell slide and the cheek cell slide. Due to the staining procedure, the morphology of the bacterial cell will be clearly seen when examined under the oil immersion. From the observation, we can infer that Escherichia coli or called as E.coli are rod-shaped bacteria. However, the difference in their arrangement could be observed clearly. For example, E.coli were arranged in an individual manner with noticeable space between each cell, whereas as the theoretical manner, Bacillus subtilis should to be longer than E.coli. Thus, the bacteria Staphylococcus aureus appears oval shaped, like a bunched grape like clusters. It is also very small in size compared to the other two bacteria.

Questions

1) How would a stained preparation appear under oil-immersion objective without the oil between the slide and the objective lens? Why if you don’t know, try it. When the specimen was observed under the microscope without the oil-immersion, the image that appear was clear and could be seen as well. But, after using the oilimmersion objective to observe the stained, the image of the stained specimen was very clearly and the image seems to arise clearly. 2) What are the structural differences between the animal and plant cell? Could you observe this exercise? The differences between the animal and plant cell are shown in the table below Differences Cell wall Shape Chloroplast

Cilia Vacuole

Animal cell ( cheek cell ) Absent Round shape (irregular) Absent

present Much smaller than plant cells

Plant cell ( onion cell ) Present in the formed of cellulose Rectangular shape (fixed) Present because they make their own food Most plant cell do not contain cilia Large central vacuole

3) Could you detect the presence or the absence of the structures in question 2in the bacterial cell? Why? No, the structures of the bacterial cells cannot be observed clearly to detect the presence of their different structures like the cell membrane, cytoplasm, the nucleus and their cell wall. This is because, the bacterial cell is very small to observe it, it cannot be observed clearly with the total magnification of 1000x but have to above than that. For example, like the staphylococcus aureus. But, it could be clearly seen with the use of oil-immersion between the slide and the objective lens. For example, Escherichia coli or called as E.coli.