Functional Anatomy of Prokaryotic Cells Flashcards
What are the basic shapes of bacteria?
- Coccus (spherical)
- Bacillus (rod shaped)
- Spiral
What are the 5 arrangements of cocci after division?
- Diplococci
- Streptococci
- Tetrad
- Sarcinae
- Staphylococci
What are the 4 arrangements of bacilli after division?
- Single bacillus
- Diplobacilli
- Streptobacilli
- Coccobacillus
What are the 3 shapes of spiral bacteria?
- Vibrio
- Spirillum
- Spirochete
How do spirilla more and how about spirochetes?
- Spirilla move via flagella
2. Spirochetes move via axial filaments
Give an example of a common pleomorphic bacterium
Corynebacterium
What is glycocalyx? What is it composed of?
- The bacterial glycocalyx is a viscous, gelatinous polymer
2. Composed of polysaccharide, polypeptide or both.
What are the two forms of glycocalyx on the outside of bacterial cells?
- If glycocalyx is firmly attached to the cell wall, it is a Capsule
- If glycocalyx is loosely attached to the cell wall, it is a slime layer
Why are bacterial capsules virulent sometimes?
Or: Importance of glycocalyx/capsule (4 key points)
- Capsules often protect pathogenic bacteria from phagocytosis, thus, can adhere to host cell surface and colonize easily
- Glycocalyx (capsule) can be a source of nutrition (sugar) when energy stores are low
- Glycocalyx can protect a cell against dehydration
- Viscosity of glycocalyx may inhibit the movement of nutrients out of the cell
Give some examples of common encapsulated bacteria
- Bacillus anthracis (some are not encapsulated)
- Streptococcus pneumoniae
- Streptococcus mutans (cause dental caries)
- Klebsiella
Some bacteria have flagella, what are the 4 arrangements?
- Monotrichous (a single polar flagellum)
- Amphitrichous (a tuft of flagella at each end of the cell)
- Lophotrichous (2 or more flagella at one pole of the cell)
- Peritrichous (flagella distributed over the entire cell)
What is Taxis? What are the two common forms?
- Taxis is a stimulus that a bacterium move toward or away from
- Two forms: chemotaxis and phototaxis
- - Chemotaxis: ex. O2, ribose, galatose
- - Phototaxis: light
Why is it important to perform flagella stain?
The Flagellar (H) protein functions as antigens in Gram (-) bacteria
Name two common spirochetes, and diseases they cause
- Treponema pallidum: Syphilis
2. Borrelia burgdorferi: Lyme disease
What other two appendage structures besides flagella do many Gram (-) bacteria have and their functions
- Fimbriae: enable cells to adhere to surfaces, including the surfaces of other cells
- - Example: Neisseria gonorrhoea - Pili: join bacterial cells in preparation for the transfer of DNA from one cell to another