Chapter 2 (Test 2) Flashcards
Endospores
Resistant to heat, chemicals, radiation, UV Survival structures Bacillus, Clostridium species No Archaea
Endospore conversion back to
to vegetative cell
Structure of the bacterial endospore
Spore coats-layers of spore-specific proteins Cortex-loose peptidoglycan Exosporium-thin protein covering Core-cell constituents DNA
Chemical constituents of the bacterial endospore
- Dipicolinic acid-calcium complex in core
- Small acid-soluble proteins (SASPs)
Dipicolinic acid-calcium complex in core
10% of spore Reduces water availability Increases heat resistance Increases chemical resistance Intercalates in DNA Prevents heat denaturation
Small acid-soluble proteins (SASPs)
Bind DNA—UV, desiccation, dry heat
Carbon and energy source for outgrowth
Gliding motility
Filamentous or rod-shaped cells:
Cyanobacteria—Polysaccharide secreted onto surface pulls cell along
Flavobacterium—Proteins on cell surface
Microbial taxis
Movement towards or away from a an agent
Cell surface receptors
Chemotaxis of peritrichously flagellated cell
Other taxes
Phototaxis—light
Osmotaxis—high ionic strength
Hydrotaxis—water
Aerotaxis—oxygen