Term
| What do the latin bacterial family names end in? How do we note the genus and species? |
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Definition
-aceae (ace-ee-ay) e.g. Enterobacteriaceae
-Genus and species are italicized, and genus is often abreviated to just the first letter (which is capitalized) |
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Term
| Go over some of the structural differences between gram+ vs gram- bacteria cell envelopes? Give a drug example? |
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Definition
Gram+
-Thick peptidoglycan layer
-Not surrounded by outer membrane (so no associated proteins or *periplasmic space)
-Has teichoic acid rather than LPS (similar in function)
Gram-
-Thin (light staining) peptidoglycan layer
-Has outer membrane and periplasmic space (membrane contains porins, LPS, and other proteins)
-Has LPS with it's antigenic *lipid A portion
-Both have the regular plasma membrane with associated cell wall synthesizing enzymes (target of penicillin) |
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Term
| Which types of cells can have a capsule? What does it do? What is it composed of? Exception? |
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Definition
-The capsule (AKA slime layer or glycocalyx) functions to protect both gram+&- from phagocytosis until opsonized
-It is composed of polysaccharide gel except in the case of B. anthracis where it is a polypeptide
-Note also that it is immunogenic, in general |
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Term
| What are the components of LPS and what do they do? In what cells? |
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Definition
-Lipid A portion (toxic)
-Polysaccharide (immunogenic)
-Only in gram- |
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Term
| What are mycolic acids? Where do we see them and what do they do? |
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Definition
-Mycolic acids are a membrane component seen in acid-fast bacteria only and confers a resistance to drying and chemicals
-Somewhat analogous to LPS and teichoic acid |
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Term
| When do we not see a peptidoglycan cell wall? What's the disease? How do we treat it? What is the usual roll of the cell wall? |
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Definition
-Mycoplasma pneumoniae have no peptidoglycan cell wall (instead they have a membrane with sterols, like euk cells, that they steal from host serum)
-The disease it causes is walking pneumonia*
-Can't treat with any drugs that target cell wall (like penicillin), so we treat instead with erythromycin (50S)
-Usually the cell wall protects from osmotic damage |
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Term
| What do we find in the periplasmic space and which cells have it? |
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Definition
-Gram- cells have it
-It is the space between membranes and contains enzymes for breaking down large molecules |
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Term
| What are the types of pilus/fimbria and which cells typically contain them? What is their purpose? Composition? |
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Definition
-They can be common, sex, or virulence types and are found primarily on gram- cells
-They function in adherence
-It is composed of the glycoprotein pilin |
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Term
| In which cells do we find flagellum? Purpose and composition? |
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Definition
-We see it in both
-It is for motility and is composed of the protein flagellin |
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Term
| In what cells do we find axial filaments (specifically)? What do they do? |
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Definition
-We find them in spirochetes (gram- type)
-They are "internal flagellum" which are in the periplasmic space and allow a corkscrew type of motility
-See in Borrelia burgdorferi (Lyme disease), Treponema pallidum (syphilis), and others |
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Term
| What are the ribosomes in bacteria composed of? |
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Definition
-A 30S and a 50S
-The 30S has a 16S in it
-The 50S has a 23S and 5S in it |
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Term
| Specifically, in which bacteria do we find endospores? What is it coated with that is extra? What is the purpose? |
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Definition
-It is found in **Bacillus and **Clostridium genera (gram+)
-They are covered in an extra thick, cross-linked peptidoglycan layer, and then a keratin layer also
-A normal bacterial cell goes into this state when conditions are bad and can stay viable for many years
-Antrax spores and staph spores are an example
-Note that the progression is from vegetative cell to spore (vegetative as in growth, i.e. normal) |
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Term
| What is the lag phase of cell growth? |
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Definition
-It is in the beginning when the cells are gearing up for division (no increase in cells here)
-Detoxifying medium and turning on enzymes |
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Term
| What is the log phase? What do we call the time interval involved? |
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Definition
-It is when the cells are actively dividing by *binary fission in a logarithmic fashion (x2 per time)
-The time interval it takes for each division is called the **generation time |
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Term
| What are the two other phases of the bacterial growth curve and what do they mean? |
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Definition
-Stationary phase and death phase
-In the stationary phase new cells = dying cells as the medium reaches the maximum amount of cells it can support
-May be from toxic byproducts or nutrient shortage
-The death phase occurs as more cells die than are made (nutrients depleted or toxic levels too high) |
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