Gram Staining
a method of differentiating bacteria
With a technique called gram staining, we can differentiate between so-called gram-negative bacteria and
gram-positive bacteria. Watch the short informative video to complete the questions below.
1- Why are the cell walls important for bacterial cells? Explain and draw a simple diagram.
2- Peptidoglycan, or murein, is the substance that makes up the ___________________.
3- It is made out of ____________________ and _____________________, which creates a _________
structure.
4- Whether we call a bacterium gram-positive or gram-negative depends on their _____________ to the
gram stain.
5- Differences in gram-negative and gram-positive bacteria’s cell walls: Fill in the missing information, draw a
neat visualization using color or patterns, and label it.
_______________________________
-
thinner cell wall (only 1 layer of peptidoglycan)
cell wall is in between two bilipid membranes
(diderms)
_______________________________
-
thick cell wall (up to 30 layers of peptidoglycan)
monoderm (single plasma membrane)
6- The staining process starts with a dye that is ______________ in color.
7- Gram-positive bacteria turn _______________. Gram-negative bacteria turn _______________.
8- Explain why there is a difference in the staining.
9- Explain the importance of staining bacteria.
Video link: https://www.youtube.com/watch?v=Didrc3wJ3E8