What are the three general shapes of prokaryotes?
- Cocci (spherical)
- Bacilli (rod-shaped)
- Spirilli (spiral-shaped)
Cocci are singularly referred to as coccus, bacilli as bacillus, and spirilli as spirillium.
What is the composition of the cell walls of eubacteria?
Peptidoglycan
Peptidoglycan is made of disaccharides and peptide fragments.
What technique is used to identify the two major types of bacteria based on their cell wall composition?
Gram stain
This technique involves adding dyes to bacteria to differentiate between gram positive and gram negative bacteria.
What color do gram positive bacteria appear after staining?
Dark purple
Gram positive bacteria have a large amount of peptidoglycan in their cell walls.
What color do gram negative bacteria appear after staining?
Light pink
Gram negative bacteria have less peptidoglycan and an outer lipid layer.
Why is it important for physicians to know the type of cell wall present in bacteria?
To prescribe the proper antibiotic
Some antibiotics work by attacking the cell wall of bacteria.
How do some prokaryotes move?
- Using flagella
- Gliding over a layer of secreted slime
Prokaryotic flagella are made of filaments, unlike eukaryotic flagella which are made of microtubules.
True or false: All prokaryotes are stationary.
FALSE
Some prokaryotes use flagella for movement toward light, higher oxygen concentration, or essential chemicals.
