Topic #3 - Cell Structure Flashcards
Cell Wall chemistry
Chemically Distinct - peptidoglycan is not anywhere else on planet
Periplasmic Space
Between Wall & Membrane
Cytoplasmic Membrane (or Plasma Membrane)
Selectively permeable membrane - moves stuff in & out. Contains lipids & proteins
Nucleoid Region
Localization of genetic material - no membrane
Cytoplasmic Membrane: Permeability Barrier
Selectively permeable - Active & Passive Transport
Cytoplasmic Membrane: Energy
Proton Motive Force: Charge gradient that creates energy (Also conservation)
Protein Anchors (Receptors)
Integrated or otherwise proteins - important for Transport, Chemotaxi & bioenergetics
Water Polarity
Positively charged hydrogen side = Ability for it to be a universal solvent (hydrophilic)
Hydrophilic
Water Loving - polar molecules
Hydrophobic
Water Fearing - Non-polar molecules
Amphipathic
Both polar & non-polar
Lipids in membranes
Lipid Amphipathicity
Fatty Acid=Hydrophobic
Glycerol phosphate=Hydrophilic
Cell membrane overview
6-8 nm thin
Lots of proteins
Unit Membrane
Integral Protein
Embedded all the way through membrane (transport). Hard to get rid of.
Peripheral proteins
Firmly assocated with membrane (usually stuck on integral membranes)
Unit Membrane
The phospholipid bilayer + Integral proteins. The whole kitten kaboodle
Fluid Mosaic Model
Proteins not fixed in space - mobile. (pieces of meat sliding on heating pan with no fixed position)
Hopanoids
Bacterial cholesterol - for mobility of proteins in unit membrane. Similar to cholesterol. Most abundant molecule on planet.
Bacteria/Eukarya: Membrane Lipids
Linkage of side chain & glycerol with Ester bond (organic acid group)
Fatty Acid Sidechain
Archaea: Membrane Lipids
Linkage of side chain & Glycerol with Ether bond (No org. acid group)
Hydrocarbon Side Chain (Isoprene)
Monolayer
Found only with tetraethers (super strong) in Archaean hyperthermophiles.
Contrasts with bilayer - no hydrophobicity in between 2 lipids - just one long lipid.
Permeability: Simple Diffusion
Scarce - need small size & uncharged.
Oxygen, CO2 & water are biggest diffusers.
Why water diffuses
Flexible membrane & weak hydrophobic forces in the middle.
Specific Transport Types
Active: Spends energy - against gradients
Passive: No energy - with gradients
Simple Transporters
- Uniporter
- Antiporter
- Symporter
Uniporters
No PMF used - Passive transport QED facilitated diffusion
Antiporter
Use PMF - H+ & a substrate move in opposite directions
Symporter
Use PMF - H+ & substrate move in same direction