Most species of bacteria can be broadly divided into two groups, known as gram-positive and gram-negative ... in the chemical composition of bacterial cell walls that makes a difference in the ...

This is because the cell wall retains the color of the staining technique developed by Hans Christian Gram in 1884. Experts divide them into Gram-positive cocci or bacilli, depending on their shape.

Gram-positive bacteria are bacteria with thick cell walls. In a Gram stain test, these organisms yield a positive result. Here’s why knowing whether the result is positive or negative is important.

Gram-positive bacteria show blue or purple after Gram-staining in a laboratory test. They have thick cell walls. Gram-negative bacteria show pink or red on staining and have thin walls.

Some bacteria have a cell wall composed of peptidoglycan, a polymer of sugar and amino acids. These “gram-positive” bacterial cells retain the colour of a stain – usually a complex of ...

It is very important to perform the Gram stain on _____ _____ because as Gram-positive cells age, they may loose their ability to retain the crystal violet dye. II. Acid-fast stain ...