BIO 202 L
Cytochemistry: Animal and Plant Tissues
Lab Performed: October 4th, 2011
Lab Submitted: November 16th, 2011
Day in and day out; Scientist worldwide work closely with various cells to study their functions, their components, and their complex structures. In Bio 202 one way we’ve learned to examine a cell is by taking advantage of the differences within the chemical reactivity of the molecules located within (Lab Manual, Chp. 5). Major biological molecules such as Polysaccharides, lipids, nucleic acids and proteins can be detected with in cells by a technique known as Cytochemistry. Cytochemistry is the practice of fixing, staining, and examining cells (Lab Manual, Chp. 5). Cytochemistry is an in situ experiment, meaning that any work performed is done on a normal, intact cell. The practice of fixing is important because it prevents the loss of components from their locations, likewise staining is equally important because it helps us to easily identify components in a cell by increasing the contrast between the different molecules. Overall, Cytochemistry reveals the presence of specific molecules, their distribution within the cell, also its form and structure (Lab Manual, Chp. 5). So the questions we begin to ask sounded like, What stains reveal specific molecules in plants?, Which stains show the molecules distribution within the cell in animals?, and What macromolecules do they actually reveal? In lab we worked with several different stains. The most commonly used stains were fast green which is used to stain proteins. Periodic acid-Schiff stain (PAS), which is used to stain carbohydrates. Feuglen stain which is used to stain DNA. Sudan Dye III which is used to detect lipids and Azure B which is used to stain DNA and RNA from blue to purple. In this lab, we were able to observe several different tissues and the major structures of each cell, while also indicating the colors we saw in each. Using histology the study of the structure...
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