green algae Flashcards
green algae
relative absence of accessory pigments for chlorophyll colours are unmasked
Unicellular
(motile and nonmotile)
Colonial
Colonial (motile or nonmotile) – loose aggregations of cells held together by mucilage or intercellular connections
Coenobium – cell number fixed at time of development (e.g., Volvox, Hydrodictyon, Scenedesmus)
Filamentous
Uniseriate to multiseriate
Branched or unbranched
Heterotrichous – differentiated into erect and prostrate parts
Siphonous / coenocytic
multinucleate, acellular
some species cell wall
- calcium carbonate
- glycoproetin
Some motile forms lose flagella during certain phases of lifecycle, becoming
palmelloid
palmelloid
Applied to an algal colony composed of an indefinite number of non-motile cells embedded in a gelatinous or mucilaginous matrix. It may occur as a non-motile phase in a normally motile species
some motile by
mucilage extrusion
eyespot
when present, located in chloroplast, usually in anterior portion of cell near base of flagellum
Consists of one to several lipid droplets, usually located between outermost band of thylakoids and chloroplast envelope
Usually orange-red colour from carotenoids in lipid droplets
some species contain photoreceptor
consisting of chrmophore
-measures light at different time intervals as cell change its position relative to light
axial
central
parietal
edges
thylakoids
stacked in groups of two to six (lamellae) with pseudograna
pseudograna
areas of stacked in columns by partial overlap of thylakoids
pyrenoids
embedded in chloroplast and often penetrated by thylakoids, associated with true starch deposition
starch is stored in
chloroplast
photoheterotrophic
(use organic carbon only when light available and when limited by dissolved inorganic carbon supply
Phycoplast
algae made- Found in simpler forms (Chlorophycean line)
Two daughter nuclei close together
After mitotic division, spindle fibers disappear and are replaced by more microtubules perpendicular to plane of division
New cell wall forms across microtubules by furrowing (ingrowth of cell membrane) or cell-plate formation (outward growth from centre)
Phragmoplast
wall made - Found in higher green algae and more advanced plants (Charophycean line)
After mitotic division, two daughter nuclei held far apart by persistent spindle fibers perpendicular to plane of division
Golgi vesicles aggregate on spindle fibers and form new cell plate via furrowing or cell plate
