CYANOBACTERIA Flashcards
formerly called the blue green algae
Cyanobacteria
comprise a group of oxygenic photosynthetic prokaryotes
they lack membrane-bound nucleus and complex organelles.
Cyanobacteria
Cyanobacteria cell membrane is equipped with simple, flattened vesicles called
thylakoids
thylakoids contain _______ that enables them to release oxygen through photosynthesis much like algae and plants.
chlorophyll a
This release of oxygen by cyanobacteria had dramatically changed the earth’s atmosphere from a
reducing to an oxidizing
The cyanobacteria that successfully lived as symbiont in other prokaryotes also led to the evolution of photosynthetic eurkaryotes based on
endosymbiotic theory of the origin of eukaryotes
Recent molecular studies, however, now classified the prokaryotes under two domains
Bacteria and Archaea
Cyanobacteria occur in various body forms:
coccoid or unicellular, colonial and filamentous.
occur singly
coccoid or unicellular forms
voluminous and fluffy covering found surrounding the cells of cyanobacteria
mucilaginous sheath
comprises the cellulose fibers aligned reticulately within the matrix
mucilaginous sheath
multicellular form
Such filamentous forms may either have true branching or false branching filament
trichomate or filamentous forms
in colonies of two or more cells enclosed in a gelatinous or mucilaginous sheath.
Colonial
composed of a single row of cells
uniseriate
composed of several rows of cells, bracnhed
multiseriate
with similar cells
homocystous
with specialized cell called heterocyst or heterocyte for nitrogen fixation
heterocytous
cyanobacteria are traditionally classified under five orders
Order Chroococcales
Order Pleurocapsales
Order Oscillatoriales
Order Nostocales
Order Stigonematales
solitary cells, aggregations and colonies not reproducing by spores
Order
Order Chroococcales
solitary cells, aggregations and short filaments reproducing by spores
Order
Order Pleurocapsales
unbranched homocystous filaments, i.e. without heterocysts and akinetes
Order
Order Oscillatoriales
unbranched filaments with heterocysts and akinetes
order
Order Nostocales
branched filaments (sometimes multiseriate) with heterocysts and akinetes
Order Stigonematales
orders that are yet to be supported by phylogenetic studies
Order Chroococcales Order Pleurocapsales Order Oscillatoriales