Chapter 3 Flashcards
Membrane Strengthening Agents
- Sterols
- -Rigid, planar lipids found in eukaryotic membranes. Strengthen and stabilize.
- Hopanoids
- -Similar to sterols
- -Present in bacterial membranes.
Archaea Membrane
- Ether linkages in phospholipids
- Have isoprenes
- Major lipids are glycerol dithers and tetra ethers.
Transport systems (prokaryotes)
- Three major classes of transport systems in prokaryotes:
- -simple
- -group translocation
- -ABC system
- All require energy.
Transport events
Three transport events are possible:
- Uniporters (one direction)
- Symporters (co-transporter)
- Antoporter (transports molecules in both directions)
Group translocation
-Transported substance is chemically modified
ABC systems
-Uptake of organic compounds and inorganic nutrients.
Protein Export
Translocases: exports proteins.
Peptidoglycan
- Rigid layer that provides strength to cell wall.
- Formed by joining peptides.
- Found ONLY in bacteria.
Gram + vs. Gram -
Cell wall:
- -gram+ is thick layer of peptidoglycan.
- -Contains TEICHOIC ACIDS (polymer).
- gram- is complex and multi-layered.
- LPS layer
- Periplasm layer
- Porins: permeable to small molecules.
Archaea Cell Walls
- No peptidoglycan.
- Pseudomurein: polysaccharide layer.
- Fimbriae.
- Pili.
Sulfur globules
-gram negative prokaryotes can store sulfur for energy.
Gas vesicles
-Gas filled structures made of protein that make cells buoyant.
Endospore structure
- Exosporium
- spore coat
- cortex
- core
- SASPS
Flagellar orientation
- monotrichous: single
- amphitrichous: two
- lophotrichous: two or more
- peritrichous: all over
- atrichous: none
Microbial Taxes
Taxis: directed movement in response to chemical or physical gradients.
- chemo:chemicals
- photo:light
- aero:O2
- osmo:ions
- hydro: H2O
Measuring chemotaxis
Measured by inserting a capillary tube with an attractant or repellent in a medium of motile bacteria.
