How will age affect gram stain?

1. How does age affect Gram stain?
2. What will happen if you Gram stain cells of an old culture?
3. Why is the age of the culture important in gram staining?
4. Which of these factors will affect your Gram stain results?
5. Which step is most likely to cause poor results in the Gram stain?
6. Why is it important to use older cultures when performing the Endospore stain?
7. What is the purpose of Gram staining what structures does the Gram stain affect?
8. How does the culture affect the results of an Endospore stain quizlet?
9. What are some consequences of leaving a stain on a bacterial smear too long over staining )?
10. What is the advantage of the Gram stain over the simple stain?
11. Why Will old Gram positive cells stain gram negative?
12. What is the importance of Gram staining in microbiology?
13. Why do we use positive and negative controls in the Gram stain?
14. What would happen if you Gram stained human cells?

How does age affect Gram stain?

How does the age of a culture affect the gram stain reaction? a. Old cultures can convert to gram-variable or gram-negative giving erroneous results. ... If done too long, gram-positive can look gram-negative and if done too short, gram-negative and look gram-positive.

What will happen if you Gram stain cells of an old culture?

Cells from old cultures may stain Gram negative even if the bacteria are Gram positive. ... A Gram negative bacterium contains less peptidoglycan and more lipid than a Gram positive organism. These chemical characteristics cause more effective and rapid removal of dye complex when decolorizer is applied.

Why is the age of the culture important in gram staining?

what is an optimum culture age for a valid gram reaction? old cultures of gram positive cells may not retain stain as well as younger cultures and could give false negative results (ex) pink cells. Cultures that are 16-18 hrs are best.

Which of these factors will affect your Gram stain results?

The many variables that can affect this stain are age of the culture, amount of decolorizer used, the time of decolorization, the type of organism (acid-fast bacteria and spores do not stain well), thickness of the smear, and the general care of the stainer.

Which step is most likely to cause poor results in the Gram stain?

Excessive Decolorization

It is clear that the decolorization step is the one most likely to cause problems in the Gram stain.

Why is it important to use older cultures when performing the Endospore stain?

Endospore staining is considered a structural stain b/c it is used to highlight a specific structure in the cell. ... To improve the odds that spore formers can be detected, most methods suggest using cultures that are 18-36 hours old. Older cultures are more nutrient depleted causing sporulation.

What is the purpose of Gram staining what structures does the Gram stain affect?

The Gram Stain is a differential staining technique that allows us to differentiate gram negative cells from gram positive cells based upon the chemistry and structure of their cell walls. After completing the staining protocol, gram positive cells appear purple while gram negative cells appear pink.

How does the culture affect the results of an Endospore stain quizlet?

How does the culture affect the results of an endospore stain? If the culture is a harsh environment there would be more spores than vegetative cells. The same goes vise-versa. What color are endospores after a Gram stain is performed?

What are some consequences of leaving a stain on a bacterial smear too long over staining )?

. What are some consequences of leaving a stain on a bacterial smear too long (over-staining)? Consequences of over-staining are that the cell wall may be broken up or completely destroyed which would result in a loss of morphological characteristics of the bacterial cell.

What is the advantage of the Gram stain over the simple stain?

What is the advantage of the Gram stain over a simple stain such as methylene blue? Gram staining highlights different bacteria types through the use of special dyes. It aids in the diagnosis of a specific organism and tells the difference between gram negative and gram positive bacteria.

Why Will old Gram positive cells stain gram negative?

Old cultures tend to lose the peptidoglycan cell walls, which predisposes gram-positive cells to be gram-negative or gram variable. Gram stain is not useful for organisms without a cell wall like Mycoplasma species, and for smaller bacteria like Chlamydia and Rickettsia species.

What is the importance of Gram staining in microbiology?

The Gram stain is the most important staining procedure in microbiology. It is used to differentiate between gram positive organisms and gram negative organisms. Hence, it is a differential stain. Gram negative and gram positive organisms are distinguished from each other by differences in their cell walls.

Why do we use positive and negative controls in the Gram stain?

The positive and negative controls are bacterial smears we use to test if the Gram stain was performed properly. If the positive and negative controls are not as expected, you can not trust that the stain was performed properly. As a Positive Control we use a known Gram-positive bacteria.

What would happen if you Gram stained human cells?

If you performed a Gram stain on human cells, what would happen? NO cell walls, the cells would not hold the stain, ETOH (alcohol) would destroy the membranes (phospholipid bilayer).