cyanobacteria

Question 1

how big are cyanobacteria

Answer 1

2-100 um

Question 2

outline some characteristics of cyanobacteria

Answer 2

• blue green algae
• gram negative bacteria
• only photosynthetic prokaryotes to produce o2

Question 3

how are cyanobacteria important

Answer 3

first organisms to produce oxygen into the atmosphere 2.5 billion years ago

Question 4

what have we used as ancient evidence to prove the existence of cyanobacteria

Answer 4

presence of stromatolites

Question 5

what are stromatolites

Answer 5

rock like structures made of cyanobacteria which are used as modern day examples of life in Precambrian times

Question 6

what are some physical characteristics of the cyanobacteria

Answer 6

• thylakoids
• slime coats
• peptidoglycan layer
• phycobilisome = protein complexes in the membrane

Question 7

how are cyanobacteria pivotal for the evolution of life

Answer 7

it was hypothesised that they gave rise to the first eukaryotic cell via endosymbiosis

Question 8

what are the different classifications based on the number of membranes for endosymbiosis

Answer 8

• primary endosymbiosis
• secondary endosymbiosis
• tertiary endosymbiosis

Question 9

what do phycobilisomes contain

Answer 9

• phycoerythrin
• phycocyanin
  allows cyanobacteria to capture a wider spectrum of light increasing photosynthetic efficiency

Question 10

how are cyanobacteria involved in nitrogen fixation

Answer 10

they are capable of fixing nitrogen converting nitrogen into nitrate or ammonia

Question 11

how are cyanobacteria involved in marine ecosystems

Answer 11

• grazed on by reef organisms
• provide nitrogen to coral reef ecosystems
• important in calcification and decalcification
• symbiosis in sponges and ascidians

Question 12

how are cyanobacteria extremophiles

Answer 12

• flexible metabolism and lifestyle
• survive extremely high and low temps
• able to colonise infertile substrates

Question 13

what are the different types of cyanobacterial cells

Answer 13

• single cells
• colonies
• filaments with specialised cells

Question 14

name the three different types of cells found in filamentous cyanobacteria

Answer 14

1) akinete = resting stage
2) heterocyst’s = used for nitrogen fixation
3) hormogonia

Question 15

how are hormogonia used in asexual reproduction

Answer 15

short piece of trichome found is filaments which detaches from the parent and glides away

Question 16

what are the main morphological groups of cyanobacteria

Answer 16

• unicellular
• filaments lacking specialsed cells
• exospores
• endospores
• filaments with heterocysts and akinetes
• filaments with true branching

Question 17

what are synechocystis

Answer 17

a unicellular spherical cell which produces asexually and found in freshwater

Question 18

name some characteristics of synechoccus

Answer 18

unicellular
prokaryotic autotrophic picoplankton
fresh water strains
main source of primary production in marine waters

Question 19

what are trichodesmium (sea sawdust)

Answer 19

a non-heterocystous cyanbacteria
fixes nitroge without heterocysts
gas vesicles regulate buoyancy

Question 20

what are spirulina

Answer 20

fresh water species
occurs in tropical/subtropical lakes with high PH
used in commercial production

Question 21

what are nostacales

Answer 21

colonial filaments
terrestrial and freshwater species
forms loose clumps in the soil

Question 22

what is BMAA

Answer 22

a neurotoxin produced by some cyanobacteria which can cause neurodegenerative diseases like alzheimers

Question 23

why are cyanobacteria good to use in biotechnology

Answer 23

• minimal nutrient requirements
• high photosynthetic efficiency
• improve fertility by N fixation
• produce high value compounds