Is a coccus or a rod more likely to survive in a moist environment?
Cocci, with their low surface to volume ratio are less efficient at exchange with the environment than rods, but are at an advantage in a dry environment where they lose water dehydrate more slowly than rods.
What does rods and cocci in bacterial morphology mean?
Bacteria exhibit a wide variety of shapes but the commonly studied species of bacteria are generally either spherical in shape which are called cocci (singular coccus) or have a cylindrical shape and are called rods or bacilli (singular bacillus).
What is the advantage of rod shaped bacteria?
Another benefit of a rod-like shape is the inherent breaking of symmetry, allowing the cell to concentrate molecules at specific cellular locales. Despite their small size, bacteria are capable of concentrating proteins at different locations in the cell.
What are some consequences of Overstaining?
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 happens if you leave crystal violet on too long?
Do NOT decolorize for a full minute! If the decolorizer is left on too long, even gram positive cells will lose the crystal violet and will stain red.
Does Carbolfuchsin stain acid fast negative cells?
Are acid-fast negative cells stained by carbolfuchsin? If so, how can this be a differential stain? Yes they are initially stained by carbolfuchsin but the decolorizing step, acid alcohol, removes stain from acid fast negative cells while acid fast positive cells retain the stain.
What is the difference between rods and cocci?
What is this? Cocci (or coccus for a single cell) are round cells, sometimes slightly flattened when they are adjacent to one another. Bacilli (or bacillus for a single cell) are rod-shaped bacteria.
What happens if you leave safranin on for too long?
What is the purpose of emulsifying the sample in serum in this staining procedure?
IN PLACE OF HEAT FIXING, CELLS MAY BE EMULSIFIED IN A DROP OF SERUM TO PROMOTE THEIR ADHERING TO THE SLIDE. CAPSULES ARE NEUTRALLY CHARGED. THIS BEING THE CASE, WHAT IS THE PURPOSE OF EMULSIFYING THE SAMPLE IN SERUM IN THIS STAINING PROCEDURE? SERUM ACTS LIKE A GLUE TO HOLD IT TO THE SLIDE.
What are rod-shaped bacteria?
As the name implies, rod-shaped bacteria tend to have a cylindrical shape as the main distinguishing factor. All rod-shaped bacteria are considered bacilli bacteria.
Why are Gram-positive cocci capable of causing airborne infections?
This protein effect on bacterial survival was marked for Escherichia coli and Salmonella typhimurium but not for Pseudomonas cepacia and Xanthomonas maltophilia. These results indicate why Gram-positive cocci and A. calocoaceticus are capable of causing airborne infections.
Is Acinetobacter calcoaceticus resistant to dry?
In the case of the Gram-positive cocci tested and one species of Gram-negative rods, Acinetobacter calcoaceticus var. anitratus, the viable cell numbers decreased by only 2 log10 by 25 days after inoculation, indicating that they are highly resistant to dry conditions.