Question

morphology morphologies Ex. 5 Questions 1. Gram-positive cultures that are older than 24hrs can stain as Gram negative sometimes. Why does this happen? 2. Why is iodine important in the Gram stain? 3. Suppose you do a Gram stain on a pure culture of Gram-positive cocci. When you view the What should slide, you see some purple spheres and red spheres adjacent to one another. you conclude and why? 으..@ 흐 真으으으뜨
Help with 1,3

4,5and 7 please God bless u

Answer 1

1. The cell wall of gram positive has higher peptidoglycon with lower lipid content than gram negative bacteria. The older culture degenerates the cell wall The bacterial cell walls are initially stained with crystal violet. The overcoloring will result in loss of primary stain causing negative bacteria to appear positive after 24hours.

3. I would conclude that bacteria was incorrectly stained because the stain has to produce either one colour purple or red but not both.

4. The most critical phase is decolorising phase which is based on the ease of crystal violet iodine complex is released from the cell. Over decolorising or leaving for long will lose the primary stain leading to give false results of indicating the gram positive to become negative.

5. Purple colour

7. To identify the type of bacteria and treat accordingly finding the resistant antibiotics in relation to it.