Bacterial Capsules, Inclusions, and Endospores Flashcards
1
Q
What is a bacterial capsule?
A
- usually composed of polysaccharides
- well organized and not easily removed
- seen well on a negative stain
2
Q
What are the advantages of having a bacterial capsule?
A
- allow for attachment to surfaces and each other (biofilms)
- helpful for nutrient absorption
- protects against desiccation, phagocytosis, viruses, detergents, toxins, and antimicrobials
3
Q
What are slime layers?
A
- similar to capsules except diffuse, unorganized and easily removed
- may aid in motility
- not seen well on a negative stain
4
Q
What are cell inclusions?
A
- aggregates of organic or inorganic material
- can be granules, crystals, or globules
- some enclosed by a single-layered “membrane” or invaginations of the plasma membrane
5
Q
What are storage inclusions?
A
- store nutrients, metabolic end products, and energy building blocks
- ex: carbon (glycogen, PHB), phosphate granules, sulfur globules, and nitrogen (cyanophycin granules)
6
Q
What are carbonate minerals?
A
- stored minerals used for stabilization in water
- ex: found in aquatic bacteria in alkaline lakes
7
Q
What are gas vesicles?
A
- store gas
- found in cyanobacteria (use oxygenic photosynthesis)
- have hollow protein tubes only permeable to gases
- aid in motility
8
Q
What are magnetosomes?
A
- magnetic bacteria
- held in invaginations of the cytoplasmic membrane
- typically found in water at the bottom (low O2 conditions)
- attracted to Earth’s magnetic field
9
Q
What are bacterial endospores?
A
- complex, dormant, survival structures formed by some bacteria
- have various locations in the cell (species specific)
- resistant to heat/freezing, radiation, chemicals, starvation, and desication
10
Q
What are the different locations of the endospore?
A
- central
- subterminal (close to end)
- terminal
- swollen sporangium (in a mother cell)
11
Q
What is the structure of an endospore?
A
- exporium on the outside
- spore coat
- outer membrane
- cortex
- germ cell wall
- inner membrane
- core
12
Q
What is the exosporium?
A
a thin outside layer of the endospore made of protein
13
Q
What is the spore coat made of?
A
proteins, very protective
14
Q
What is the cortex made of?
A
peptidoglycan, but less cross linked
15
Q
What layers of the endospore make up the vegetative cell?
A
germ cell wall, inner membrane, and core