Gram-positive -
teichoic acid, various other
polysaccharides and/or proteins and/or lipids
Gram-negative -
outer membrane composed of lipid bilayer containing lipopolysaccharide (LPS
or endotoxin) and various proteins
Membranes -
glycerol-based phospholipids with ester linkages which form typical bilayer membranes
Ribosomes -
small RNA/protein
particles which are required for protein synthesis
Chromosome - double-stranded
DNA (~5000 kbp for Escherichia coli) that contains the "blueprint" for
all cell structure and activity in regions called genes
Plasmids -
some have pieces of extrachromosomal DNA (generally circular)
that contain only a few genes, but can replicate themselves and are exchanged among
various species of bacteria
Endospore -
thick-walled structures that are highly resistant to adverse environmental conditions
(high temperature, drying, oxygen, etc.); generally formed only by bacilli, and then
each cell only forms one (endospore
stain)
Capsules -
polysaccharide "coatings"
secreted by cells (act as anchors)
Flagella -
long, thin protein (flagellin) polymers that
provide motility
Pili -
long, thin protein (pilin) polymers that act as cell "anchors" to help bacteria attach to environmental surfaces
and can assist in attaching bacterial cells one another to facilitate DNA transfer from cell to cell
Prokaryotic -
0.1-15 x 0.1-200 µm
(typically, 0.3-1 x 0.3-6 µm) rods
(bacilli), spheres (cocci), or irregular shaped (lobed, triangular, spherical, or amorphus
(no cell wall)
Membranes - structure similar to that found
in Bacteria and Eukarya, but Archaea use ether
linkages in lipids (rather than ester linkages) and
form monolayers rather than bilayers
Cell wall
protects the cytoplasm from osmotic
pressure changes and provides cell shape ... however, some
lack cell walls
Gram-positive or Gram-negative, lacks
peptidoglycan (no muramic acid or D-amino
acids); instead, possess pseudopeptidoglycan,
polysaccharide, glycoprotein or
protein
Ribosomes - 70S RNA/protein
particles which are required for protein synthesis
(act more like those of Eukarya than those of
Bacteria)
Chromosome - single (closed circular)
molecule of double-stranded DNA (one-third to one-half
as much DNA per cell as found in bacteria such as
E. coli)
Plasmids - these pieces of extrachromosomal
DNA may make up as much as 25-30% of cellular DNA
Capsules - polysaccharide "coatings"
secreted by cells (???)
Flagella - long, thin protein (flagellin)
polymers that provide motility
Pili - long, thin protein polymers that act as cell "anchors" to help archaea attach to environmental surfaces (archaeal pili have quite different structures than bacterial pili)
Eukaryotic - individual cells are generally
larger than bacterial cells
Unicellular(yeasts) or
multicellular (molds ... mycelium that is a mesh
of elongated filamentous hyphae that are frequently
branched, with perforated septa between cells to
ensure unimpeded movement of nutrients from one region
of the mycelium to another) ... some fungi are
dimorphic (change back and forth from yeast to
mold)
Cell walls contain chitin or cellulose -
protect the cytoplasm from osmotic pressure
changes and provides cell shape
Membranes - glycerol-based phospholipids
with ester linkages which form typical bilayer
membranes
Absorptive nutrient uptake
Ribosomes - 80S RNA/protein
particles which are required for protein
synthesis
Chromosome - multiple, non-identical DNA molecules
complexed with histones; the DNA contains the "blueprint" for
all cell structure and activity in regions called genes
Reproduce by:
asexual reproduction via spores
(thick-walled structures that can withstand dry,
cold, low-nutrient conditions), binary fission,
budding, hyphal fragmentation
sexual reproduction via fusion of
haploid nuclei leading to formation of spores
(thick-walled structures that can withstand
dry, cold, low-nutrient conditions)
Unicellular - microscopic, but
larger than most Bacteria or Archea
Cell walls - none, but many form a pellicle just "inside" the cytoplasmic membrane, especially in ciliates and Apicocomplexans
Membranes - glycerol-based phospholipids
with ester linkages which form typical bilayer
membranes
Pseudopodia or undilipodia (cilia,
flagella) provide motility
Cysts (dormant) formed by some
Absorptive or ingestive nutrient
uptake
Ribosomes - 80S RNA/protein particles which
are required for protein synthesis
Chromosome - multiple, non-identical DNA molecules
complexed with histones; the DNA contains the "blueprint" for
all cell structure and activity in regions called genes
Reproduce by:
asexual reproduction via binary fission
or budding
Membranes - glycerol-based phospholipids
with ester linkages which form typical bilayer
membranes
Organs and organ systems made up of tissues
of cells
Holdfasts (hooks, suckers, etc.) possessed
by parasitic forms for attachment to the host
Absorptive or ingestive nutrient
uptake
Ribosomes - 80S RNA/protein particles which
are required for protein synthesis
Chromosome - multiple, non-identical DNA molecules
complexed with histones; the DNA contains the "blueprint" for
all cell structure and activity in regions called genes
Reproduction is sexual (only) ...
via fertilized eggs that mature into offspring