Prokaryotic Cell Structure Flashcards
What is the cell size for prokaryotes and eukaryotes?
Prokaryotes- 0.2-700um
Eukaryotes- 10-200 um
What is the cytoplasmic membrane?
Thin structure that surrounds the cell
6-8nm
Vital barrier that separates cytoplasm from environment
Selectively permeable
What do bacteria and eukarya have in common?
Both have ester linkages in phospholipids
What do archaeal lipids lack?
Fatty acids
Have isoprenes instead
Describe the permeability barrier;
Polar and charged molecules must be transported
Transport proteins accumulate solutes against the concentration gradient
Describe the protein anchor;
Holds transport proteins in place
Describe the bacterial cell wall
Peptidoglycan
- rigid layer that provides strength to cell wall
- polysaccharide is composed of( NAG,NAM, DAP amino acids)
Describe gram positive cell walls;
Can contain up to 90% peptidoglycan
Common to have teichoic acids embedded in the cell wall
Describe gram negative cell walls;
Contains total 10% Peptidoglycan
Most of cell wall composed of outer membrane (aka LPS layer)
What does the lipopolysaccharide layer contain?
Core polysaccharide & O-polysaccharide
LPS replaces most of phospholipids in outer half of outer membrane
Endotoxin - the toxic component of LPS
What is contained in the archaeal cell walls?
No peptidoglycan
Typically no outer membrane
Paeudomurein
What are S-layers?
Most common cell wall type among archaea
Consist of protein or glycoprotein
Paracrhstalline structure
Describe the capsules and slime layers;
Polysaccharide layers (thin,thick,rigid,flexible)
Assist in attachment to surfaces
Protect against phagocytosis
Resist desiccation
What is fimbriae?
Filamentous protein structures
Enable organisms to stick to surfaces or form pellicles
