CYANOBACTERIA

Question 1

formerly called the blue green algae

Answer 1

Cyanobacteria

Question 2

comprise a group of oxygenic photosynthetic prokaryotes

they lack membrane-bound nucleus and complex organelles.

Answer 2

Cyanobacteria

Question 3

Cyanobacteria cell membrane is equipped with simple, flattened vesicles called

Answer 3

thylakoids

Question 4

thylakoids contain _______ that enables them to release oxygen through photosynthesis much like algae and plants.

Answer 4

chlorophyll a

Question 5

This release of oxygen by cyanobacteria had dramatically changed the earth’s atmosphere from a

Answer 5

reducing to an oxidizing

Question 6

The cyanobacteria that successfully lived as symbiont in other prokaryotes also led to the evolution of photosynthetic eurkaryotes based on

Answer 6

endosymbiotic theory of the origin of eukaryotes

Question 7

Recent molecular studies, however, now classified the prokaryotes under two domains

Answer 7

Bacteria and Archaea

Question 8

Cyanobacteria occur in various body forms:

Answer 8

coccoid or unicellular, colonial and filamentous.

Question 9

occur singly

Answer 9

coccoid or unicellular forms

Question 10

voluminous and fluffy covering found surrounding the cells of cyanobacteria

Answer 10

mucilaginous sheath

Question 11

comprises the cellulose fibers aligned reticulately within the matrix

Answer 11

mucilaginous sheath

Question 12

multicellular form
Such filamentous forms may either have true branching or false branching filament

Answer 12

trichomate or filamentous forms

Question 13

in colonies of two or more cells enclosed in a gelatinous or mucilaginous sheath.

Answer 13

Colonial

Question 14

composed of a single row of cells

Answer 14

uniseriate

Question 15

composed of several rows of cells, bracnhed

Answer 15

multiseriate

Question 16

with similar cells

Answer 16

homocystous

Question 17

with specialized cell called heterocyst or heterocyte for nitrogen fixation

Answer 17

heterocytous

Question 18

cyanobacteria are traditionally classified under five orders

Answer 18

Order Chroococcales
Order Pleurocapsales
Order Oscillatoriales
Order Nostocales
Order Stigonematales

Question 19

solitary cells, aggregations and colonies not reproducing by spores

Order

Answer 19

Order Chroococcales

Question 20

solitary cells, aggregations and short filaments reproducing by spores

Order

Answer 20

Order Pleurocapsales

Question 21

unbranched homocystous filaments, i.e. without heterocysts and akinetes

Order

Answer 21

Order Oscillatoriales

Question 22

unbranched filaments with heterocysts and akinetes

order

Answer 22

Order Nostocales

Question 23

branched filaments (sometimes multiseriate) with heterocysts and akinetes

Answer 23

Order Stigonematales

Question 24

orders that are yet to be supported by phylogenetic studies

Answer 24

Order Chroococcales Order Pleurocapsales Order Oscillatoriales

Question 25

but the 2 orders of heterocystous cyanobacteria have now been found to be a monophyletic group based on the 16S rRNA analysis.

Answer 25

(Nostocales and Stigonematales)

Question 26

class of cyanobacteria

Answer 26

Gloeocapsa.
Oscillatoria.
Spirulina.
Anabaena.
Nostoc.
Rivularia.

Question 27

relatively simple cyanobacterium

spherical cells either grow singly or in small aggregations (=colonies) held together by a firm mucilaginous sheath

The sheath is often colored and has distinct layers that delineate each cell’s contribution.

Reproduction is carried out by simple binary fission.

Answer 27

Gloeocapsa

Question 28

filamentous cyanobacterium consists of a single series of similar cells (homocystous)

shorter than wide except for terminal cells with a modified shape.

mucilaginous sheath encloses the filament

Reproduction is achieved via fragmentation

Answer 28

Oscillatoria.

Question 29

often grows in mats or interwoven filaments that may show active gliding or “oscillating” movement to adjust filament density in a mat in response to environmental conditions.

Answer 29

Oscillatoria

Question 30

proposed reason of Oscillatoria movement

Answer 30

mucilage secretion

Question 31

part of a filament Oscillatoria breaks off producing short segments

Answer 31

hormogonia.

Question 32

oftentimes distinguishable by their cell shape, greater motility and presence of gas vesicles, detach from vegetative filaments at separation discs.

grow by adding new cells.

Answer 32

hormogonia.

Question 33

his filamentous, homocytous cyanobacterium is easily distinguishable by its spiral trichome, which lacks a mucilagenous sheath. The high protein content merits its being a food supplement.

Answer 33

Spirulina.

Question 34

filamentous cyanobacterium forming heterocysts

unbranched filaments appear like a string of beads.

Answer 34

Anabaena

Question 35

specialized cells for N2 fixation

Answer 35

heterocysts

Question 36

thick-walled cells formed after a period of active growth that survive in a dormant state when conditions are unfavorable for further growth

Answer 36

akinetes

Question 37

Both are larger and with thicker walls than the vegetative cells.

Answer 37

heterocysts and akinetes

Question 38

differ from heterocysts in having granular cytoplasm with an abundance of cyanophycin granules

Answer 38

Akinetes

Question 39

This cyanobacterium is much similar with Anabaena, but has a thick and firm mucilaginous sheath which may enclose the filaments into highly visible colonies

Answer 39

Nostoc.

Question 40

highly visible colonies of Nostoc
This particular species is highly nutritious.

Answer 40

Nostoc commune

Question 41

This forms colonies in which the sheaths of one filament are confluent with others. The sheaths are heavily encrusted with lime and are very firm.

the filaments are polarized with a terminal heterocysts under conditions of low nitrogen concentration. When grown in media containing nitrogenous compounds, heterocysts are not formed and the trichomes are not tapered, thus, resembling species of genera such as Oscillatoria.

Answer 41

Rivularia.