Abstract
The experiment at hand is investing on the safe usage of the microscope as vital tool in the study of cell biology. It is focusing on two main microscopic techniques used in the many biological laboratories. These are bright-field and phase-contrast microscopy. To achieve this its looks at the different method employed in the preparation of microscopic slide materials as well as examines the best most correct method of focusing the prepared slides in using the microscope.
Introduction
The study of biology entails getting of the insight information for both large and minute biological objects. The study of very small objects has not been possible with unaided eye. Therefore, the invention of the microscope is viewed as major break through in cell biology. The microscope is the most significant basic tool for a cell biologist, which enables the study of minute biological object that cannot be seen with naked eyes (Rudolph 4). Since its invention in the late 16th century by Janssen, the microscope developed as useful magnifying equipment in biological laboratories. Whereas earliest microscopes depended on the visible light in their functions, several advancements have been made leading to production of more sophisticated ones. The compound microscope which comprises of more lenses than the simple light microscope is the most common in biological laboratories for the study of microbes and other minute biological objects such as animal and plant tissues and cells (Cox 47).
In the study of minute biological objects, the different microscopic techniques are employed depending on the required depth of details or information. Four types of microscopic techniques that are commonly used include phase-contrast, dark-field, bright-field and fluorescence microscopy. The bright-field and phase contrast microscopic techniques are widely used in today’s biology laboratories particularly in microbiological work (Carpenter et al 3). These various microscopic techniques are suited for particular applications of study. Thus, each type has its advantages and disadvantages over the others. In order to use the microscope for the various studies in the microbiological work, cells, tissues and other biological objects undergo different treatments to reveal the necessary features required. Microbial cells such as bacteria, protozoa as well as plant and animal cells are treated with dyes, which contain either colored charged positive ions or negative ions- “(chromatophores)”. If a biological object has most of its components negatively charged, it’s stained with basic dyes such as crystal violet and methylene blue which have the cations being the chromatophores. However, for biological object that has its components being positively charged, it’s stained with acidic dyes which have the anions acting as the chromatophores (Bregman 47). The results of microscopic work depend on the adherence to the recommended procedure. This entails precision and accuracy in dispensing reagents in the entire process with the use of the appropriate apparatus or equipments.
Objectives
To study and understand the different characteristics of light microscopy employed in cell biology in studying the structural and physiological characteristics of the cells and their components.
To study and understand the proper use and care of the compound microscope.
Materials and Equipment
Plant cell from Elodea, human epithelial cell, Paramecium culture , automatic pipettes, glass slides, slide cover slips, brilliant crystal blue, methylene blue, alizarin red, janus green, Congo red, neutral red, and bismark brown, light compound microscope and its accessories, Toothpick visco-elastic resin
Methodology
Preparation of wet mount of paramecium
Using a sterilized pipette, a drop of paramecium culture medium was placed on a glass slide. 10 μl of visco-elastic resin was added and mixed with the culture medium using a toothpick. A slide cover slip was placed on top and then the slide was observed under bright-field microscopy at the different magnifications of the microscope. A sketch of the image observed was made of drawing paper. The slide was then observed under the phase-contrast microcopy and a sketch diagram was made on a piece paper.
Preparation of stained slide
Using a sterilized pipette, a drop of paramecium culture medium was placed on a glass slide. 10 μl of visco-elastic resin was added and mixed with the culture medium using a toothpick. A slide cover slip was placed on top and crystal blue stain added on one edge of the cover slip. Using a piece of “Kimwipe”, the stain solution was drawn into the wet mount. The prepared slide was observed under bright –field microscopy and the observed microscopic image was drawn. Similarly, the slide was also observed under the phase-contrast microscopy and the microscopic observed structured of the paramecium was drawn on a paper.
Examination of plant cell
Elodea leave was obtained from the plant body and placed on a clean glass slide. A drop of distilled water was added and a cover slip placed on top. The slide was then observed under the microscope using the bright-field microscopy. A clear diagram of the observed microscopic image was drawn
Examination of human cell
An epithelial cell was obtained from the cheek using a clean toothpick. The cells were mixed with a drop of distilled water on clean glass slide. A drop of methylene blue stain was added and mixed with the contents on the slide. A cover slip was placed on the top and then, the slide was observed under the microscope. The results of the observed bright-field and phase contrast microscopic images were drawn on a piece of paper.
Results
Magnification
Discussion
The microscope comprises of various parts which are coordinated with each to aid in the study of minute and complex structure found on the biological objects such a cells. The most important factor in the study of minute microscopic biological objects using the microscope is the ability of the microscope to attain high resolution. This depends on the contrast displayed by the objects. The microscope has several objective lenses which aids in the magnifying the tiny objects under study. When lens of the power of 10x is focused on the objects, the structures seen are less in number and also unclear than when a higher powered lens is used. Thus, the objective lens of 40x has gives greater resolution than 10x. The images of cells observed under 10x objective lenses were blurred. For instance, the epithelial cell nucleus was only seen when observed under 10x objective power but these were very unclear. Furthermore, it appeared as without of cytoplasm content with just the cell membranes surrounding it. This infers that it structure resembled that of single-celled organism or the prokaryotes. The plant cells observed under the bright-field microscopy also reveal important structures including the cell-wall which was absent in the epithelial cell and the paramecium cells. The cell-wall thus suggested the slight difference found in the epithelial cells which are of animal origin from the plant cells. The cell-wall found in plant cells are believed to be of significant important as it give the shape of plant cell as well as increasing support to the plant
Conclusion
Generally, the microscope is used for various studies in the biological field. This include the study of plant cells, animal cells as well as the study of unicellular cells such as the paramecium, which is a unicellular eukaryotic. Microscope is very delicate equipment, which needs a lot of care on the lenses. The microscope helps the observation of the biological object at different resolution, hence the preparation of the biological material together with the ability to scan the microscope is an important skills needed in the operation of the microscope.
Works Cited
Bregman, Allan. Laboratory exercises in cell and molecular biology. New York: Wiley ,1996
Carpenter et al. Biology Lab. Manual. University of Texas, 2007
Cox, Guy. Optical Imaging Techniques in Cell Biology. Boca Raton: CRC Press, 2007.
Rudolph, W. Biological microscopy with ultrashort laser pulses, in Tunable Laser Applications. New York: CRC press, 2009