2-7: Bacterial Cell Inclusions and Endospores Flashcards
What is an inclusion
Body or aggregate within cell, often related to storage
What is a microcompartment
Protein shells that encase specific enzymes/metabolites, cofactors
What are carbon storage polymers
Lipid polymers produced when there is excess carbon/energy. They aggretate to form large granules and are broken down when energy is needed
What is the name of the carbon storage polymer lipid used?
poly-beta-hydroxyalkanoates (PHA), the most common of which is poly-beta-hydroxybutryric acid (PHB)
Where is inorganic phosphate stored
Polyphosphate granules; broken down to produce nucleic acids, phospholipids
Where is excess sulfur stored
Sulfur storage granules
What organisms produce sulfure stoarge granules?
Made by bacteria/archaea that oxidize reduced sulfur compounds for energy
What are gas vesicles. eg?
Protein structures that keep water/solutes out, let gas in. Confer buoyancy - can bring microbe to favourable environment. e.g. cyanobacteria at surface of water = sunlight
What are microcomparments? Give an example.
Polyhedral protein shells that encase specific enzymes/metabolites/cofactors. eg. carboxyzomes
What are carboxysomes
Microcompartments that concentrate enzymes involved in carbon fixation. Leads to increased efficiency, reduces side reactions
What are some functions of microcompartments?
Protect the cell from toxic metabolites
What is an endospore
Hihgly differentiated dormant cell that survives starvation, harsh evironment
What phylum produces endospores
Firmicutes (gram +)
Are endospores the only kind of spore?
NO, diff bacteria create diff spore structures
What are endospores resistant to
Heat, radiation, drying, nutrient depletion, chemicals, etc
What is a vegetative cell
A metabolically active, growing/diving cell that become endospores upon nutrient deprivation. Can be reactivated/germinate when environment becomes favourable
Name four metabolic changes that occur when a cell changes from vegetative to endospore
Low to high Ca2+, generation of ipicolonic acid, decrease water content, generation of SASPs
How do endospores create a stable/resistant core
Dehydration of the core, Dipicolinic acid, Small acid soluble proteins
What is dehydration of the core
Water from 80% to <25%. Increases resistance to dessication, inactivates enzymes
How do dipicolinic acids help endospores
Complexed with Ca2+. Important in dehydration process, binds/stabilizes DNA
How do small acid soluble proteins help endospores
only made during sporulation. Bind DNA - make it compact, protect it from damage (UV, heat denaturation). Act as carbon/energy source during germination
What are the structures of the endospore
Core, cortex, two membranes, coat, and exosporium
What is the core of an endospore?
Where the DNA/ribosomes are held - will become the vegetative cell
What is the cortex of an endospore?
Peptidoglycan layer
