SIze comparison of microorganisms Meters Visibility scale Relative size of microbes 103 1,000um 1 mm ked eye Prokaryotes 10-4 100pm 10-5 lO um Bacillus megaterium 6 1.000 nm or Eukaryotes 1 um Escherichia coli 10-7 100nm Light microscope Mycoplasma 0810nm Virus Viruses 10-9 1 nm Electron microscope
size comparison of microorganisms Meters Visibility scale Relative size of Microbes Prokaryotes Eukaryotes Viruses Naked eye Light microscope Electron microscope
Surface area and volume relationships in cells volUme.4.2wl r Carlson a cell increases in size its surface area -to 1-2um volume ratio decreases 5rs0a=503 wore.33.5 um' Surace 15
a cell increases in size, its surface area – to – volume ratio decreases Surface area and volume relationships in cells
Shape: bacteria have a few basic shapes spherical coccus Coccus Rod-shaped bacillus spirillum
spirallum Shape: Bacteria have a few basic shapes spherical coccus Rod-shaped bacillus
Prokaryotic cell wall The cell wall of the bacterial cell is a complex semi-rigid structure that is responsible for the characteristic shape of the cell. The cell wall surrounds the underlying, fragile plasma (cytoplasmic) membrane and protects it and internal parts of the cell from adverse changes in the surrounding environment Almost all prokaryotes have cell walls
• The cell wall of the bacterial cell is a complex, semi-rigid structure that is responsible for the characteristic shape of the cell. The cell wall surrounds the underlying, fragile plasma (cytoplasmic) membrane and protects it and internal parts of the cell from adverse changes in the surrounding environment. • Almost all prokaryotes have cell walls. Prokaryotic cell wall
Schematic diagram of bacterial cell walls Grant rram Peptidoglycan 一 Peptidoglycan Membrane Membrane I Periplasm Lipopolysaccharide and protein Bacteria can be divided into two major groups, called gram-positive and gram-negative. The original distinction between gram-positive and gram-negative was based on a special staining procedure, the Gram stain
Gram+ Gram - Schematic diagram of bacterial cell walls Bacteria can be divided into two major groups, called gram-positive and gram-negative. The original distinction between gram-positive and gram-negative was based on a special staining procedure, the Gram stain