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Why do gram-positive cells more than 24 hours old stain gram-negative?
To write:
The reason for iodide can be added before the primary stain in a gram strain.
Introduction:
Staining is a method that provides variance to the microscopic image for enhanced vision under the microscope. It is a method that is extensively used for the assessment of cells and tissue components. It is often used to draw attention to the microbial structures for viewing with the help of diverse microscopes.
Explanation of Solution
Gram staining:
It is a common method that is used to distinguish two large bacterial groups based on their dissimilar cell wall components. The Gram stain process differentiates between the Gram-positive and negative bacterial groups by coloring these cells violet or red.
Gram-negative bacteria:
It loses the crystal violet stain in the Gram staining method. It is a feature of bacteria which contain a cell wall made up of thin layer peptidoglycan.
Gram-positive bacteria:
These bacteria contain a very thick cell wall of peptidoglycan. These gram-positive bacteria hold the crystal violet dye.
The reason for the gram-positive cells that are more than 24 hours old can stain gram-negative:
Because in the older cells, the cell walls become degenerate and lose the purple dye.
In the older cells, the cell walls become degenerate and lose the purple dye.
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Chapter 7 Solutions
Laboratory Experiments in Microbiology (12th Edition) (What's New in Microbiology)
- What color will a gram-negative cell be after Gram staining bythe conventional method?arrow_forwardWhat color wouod gram negative cells appear if the decolorizing step was left out of staining procedure? Why?arrow_forwardWhat is meant by Gram positive? Explain the mechanism of Gram positive staining.arrow_forward
- Which step in the Gram stain procedure is most prone to error? If done incorrectly, how might that step affect the end result?arrow_forwardDescribe why the Gram stain can differentiate between Gram positive and Gramnegative cells?arrow_forwardHow would the slide appear if the bacteria were stained with safranin, a basic red dye?arrow_forward
- Why is oil immersion necessary to see bacteria in the laboratory?arrow_forwardOne of your classmates performed a gram stain on Pseudomonas aeruginosa and found variable gram staining, with only some of the cells gram positive. What should your classmate have found ? What errors could have contributed to the variable result?arrow_forwardWhat is the importance of Gram-staining?arrow_forward
