Staphylococcus stains Gram positive. Both alcohol and acid–alcohol are decolorizers, and iodine is a mordant.
Correct Answer: Gram-negative bacteria – staphylococcus
The Gram stain begins by adding primary stain (crystal violet) to a heat-fixed smear of a bacterial culture. Heat fixing kills some bacteria but is mostly used to affix the bacteria to the slide so that they don't rinse out during the staining procedure. Then iodine is added to increase the size of the crystal violet crystals. These become entrapped in the cell wall. Next all the dye that is not entrapped is washed away with ethanol (alcohol wash). The cells are then counter-stained with safranin.
Correct Answer: 2-4-1-3
Neisseria is the genus name. Binomial nomenclature is the combination of a genus name and a second term, which identifies each species of organism. For example, the domestic cat species is Felis catus, genus Felis and species catus, and no other species of organism can have this same binomial name.
Correct Answer: Neisseria
Dyes used in negative staining, such as India ink, stain the background. The dye will not penetrate the tight layers of the capsule and the capsule will appear clear against a black background. The capsule’s resistance to staining explains why the other staining procedures fail.
Correct Answer: Negative
The genes involved in virulence often appear as groups. In bacteria, these groups are called pathogenicity islands and these occur in the chromosome or as a part of plasmids. Neither endoplasmic reticulum nor ribosomes carry virulence genes.
Correct Answer: The chromosome and plasmids
It is now well established that pathogens often carry clusters of genes whose activity results in the production of factors that increase its virulence. Bacteria typically have only one chromosome, and these virulence genes are carried either on that chromosome or on mobile genetic elements called plasmids. Clusters of virulence genes are called pathogenicity islands.
Correct Answer: Pathogenicity islands
During quorum sensing, small proteins called sensing proteins relay information about the cell’s environment to other proteins that regulate genes controlling the transcription of virulence genes. This environment-sensing mechanism is referred to as quorum sensing because it is based on cell population densities.
Correct Answer: All of the choices
All are properties of biofilms. Biofilms are aggregations of many bacterial cells which often contain polysaccharide matrices and protect bacteria.
Primary pathogens are defined by the finding that they cause disease in un-compromised hosts.
Correct Answer: Primary pathogens
A pathogen must be able to establish itself in the host (getting into a host cell, staying there, and avoid detection), cause damage, and then allow for transmission to other hosts.
Mycobacterium stains positive in the acid-fast stain and are not positive (do not retain crystal violet) in the Gram stain. Acid-fast bacteria stain poorly or not at all with the Gram stain. The Gram stain uses crystal violet as the primary stain, the decolorizer is an alcohol wash, and a positive Gram stain is purple. The acid-fast stain uses carbolfuchsin as the primary stain, the decolorizer is an acid-alcohol wash, and a positive result is red.
Correct Answer: Mycobacteria stain negative in the acid-fast stain, but positive in the Gram stain
The protein contacts ubiquitin first, then moves on to the first regulatory particle, then through the core particle and the second regulatory element to exit as protein fragments.
Correct Answer: Ubiquitin
Correct Answer: First regulatory particle
Correct Answer: Core particle
Correct Answer: Second regulatory particle