When heat fixing, what would happen to the cells or to what you actually can see after staining if too much heat were applied? 3. Crystal violet was the simple stain that we used and it is a basic stain. What is the difference between a simple basic stain and a simple acidic stain, specifically what is stained during the procedure ?
The Correct Answer and Explanation is:
. Effect of Excess Heat During Heat Fixing:
Heat fixing is a crucial step in preparing slides for staining because it helps the cells adhere to the slide and preserves their shape. However, if too much heat is applied during this process, several undesirable effects can occur. Overheating can cause cells to shrink, distort, or even lyse (break apart). When cells shrink, they may appear smaller and less representative of their actual size, making it difficult to identify them correctly under the microscope. Additionally, excessive heat can damage the cell wall or membrane, potentially causing the cells to break apart or lose their structural integrity. This can result in a poor or unclear view after staining, as some cells may no longer be intact or clearly visible.
On the other hand, insufficient heat may not effectively fix the cells to the slide, which could lead to cells being washed away during the staining process.
2. Difference Between Basic and Acidic Stains:
A basic stain (like crystal violet) is positively charged. During staining, it interacts with negatively charged components of the cell, particularly the negatively charged nucleic acids (like DNA and RNA) and the acidic components of the cell wall. In this case, the cell structures, especially the cell membrane and the cytoplasm, take up the stain and become colored. Basic stains are commonly used for general bacterial staining because they highlight the shape and arrangement of cells, making them easier to observe.
An acidic stain, on the other hand, is negatively charged. These stains typically bind to positively charged structures within the cell, such as certain proteins. Since bacterial cells and many other biological cells have a negative charge on their outer surfaces, acidic stains do not bind as easily to the cells. Instead, they may stain the background of the slide, leaving the cells themselves largely unstained or with less intense staining. Acidic stains are often used in techniques like negative staining, where the aim is to highlight the cell shape by leaving the cell itself clear against a darkened background.
In summary, basic stains are used to color the cell structures, while acidic stains are typically used for background staining, highlighting the contrast of the cell structures without coloring them directly.
