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Algae, Fungi And Mosses > Cyanobacteria > Flashcards

Cyanobacteria Flashcards

1
Q

Cyanobacteria are classified within what domain?

A

Eubacteria

Due to their simple prokaryotic cell structure and predominantly oxygen-evolving photosynthesis

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2
Q

Bacteria characteristics
-cell type
-nuclear envelope
-number of chromosomes
-chromosome configuration
-organelles
-cytoskeleton
-chlorophyll-based photosynthesis

A

Prokaryotic
Absent
1
Circular
Absent
Absent
Present

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3
Q

Archea characteristics
-cell type
-nuclear envelope
-number of chromosomes
-chromosome configuration
-organelles
-cytoskeleton
-chlorophyll-based photosynthesis

A

Prokaryotic
Absent
1
Circular
Absent
Absent
Absent

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4
Q

Eukarya characteristics

cell type
-nuclear envelope
-number of chromosomes
-chromosome configuration
-organelles
-cytoskeleton
-chlorophyll-based photosynthesis

A

Eukaryotic
Present
More than 1
Linear present
Present
Present

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5
Q

What percent of evolutionary history is Precambrian life

A

85

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6
Q

First photosynthetic organism were what and when

A

Cyanobacteria
3.5 BYA

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7
Q

How long did it take for prokaryotic life to transform the atmosphere

A

1 billion years

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8
Q

When did eukaryotic organisms evolve

A

1.5 billion years ago

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9
Q

The simplest Cyanobacteria grow as _____ cells which may be enveloped by a thin, diffuse of form gelatinous layer called a ____

A

Solitary

Sheath

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10
Q

Trichome

A

Formation of a row of cells

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11
Q

When a tri choke is surrounded by a sheath, the structure is called a _____

A

Filament

(Adjacent cells share a common cell wall)

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12
Q

Branched filaments can be ____ or ____

A

Uniseriate (composed of single row of cells

Multiseriate (composed of more than one row of cells

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13
Q

Thylakoids structure and function

A

3-6 or more thylakoids are peripherally arranged in a cell and cause a dark peripheral region

Hold complexed of photosynthetic pigments

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14
Q

Cell structure of Cyanobacteria

A

Thylakoids

Internal part of the cell is called the centroplasm

DNA appears fairly uniform but concentrated in central region (nucleoid)

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15
Q

Photosynthetic pigments

A

Cell colour depends on ratio of photosynthetic pigments which can be bright blue, green, olive, gray ish, pink or violet

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16
Q

Phycobilins

A

Accessory photosynthetic pigments that extend the range of absorbed light

-phycoerythrin
-phycocyanins
-allophycocyanin

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17
Q

Phycoerythrin

A

Appear red, absorb green (495-545 nm)

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18
Q

Phycocyanins

A

Appear blue, absorb orange and red 620nm

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19
Q

Allophycocyanin

A

Appear blue, absorb red at 650-660nm

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20
Q

Phycobilisomes

A

Clusters of pigments that adhere to thylakoid membrane

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21
Q

Chlorophyll-a

A

Absorbs 450-475 nm and 650-675 nm

Two peaks

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22
Q

Cyanobacteria uses photo systems ________ and ______ electron transport system

A

1 and 2

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23
Q

What do phycobilisomes specialize in

A

Absorbing deep penetrating green light which extends range of light absorbed into wavelengths out of the range of chlorophyll

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24
Q

Longer red wavelengths are absorbed at _____ depth than shorter blue wavelengths which _______

A

Shallower

Penetrate deeper

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25
Q

Photo acclimation

A

Proportion of pigments changed with light conditions

-green light stimulates synthesis of phycoerythrin=more efficient capture of green light than chlorophyll-a
-red light stimulates phycocyanins synthesis

26
Q

Photo acclimation in polar area

A

Relatively constant photosynthesis of polar phytoplankton appear to be a response to the persistently low, yet continuous irradiance of the polar summer.

27
Q

When are photosynthetic pigments highest

A

Peak in morning, lower in evening

28
Q

Cyanobacteria swimming

A

Protein on the cell surface generate waves (without flagella)
-1/3 of open ocean unicellular Cyanobacteria are motile
-move at 5-25mm/a while rotating long axis
-motion optimized light exposure
-important to avoid UV damage

29
Q

Motor cargo proteins

A

Move along a continuous looped helical track creating distortions

Protein that moves Cyanobacteria

30
Q

Oscillation

A

Various movements of many strains can include trichome bending, rotation and gliding

Movements may be due to contradict proteins in the cell walls in combination with signalling between cells along the trichome

31
Q

Gas vesicles in Cyanobacteria

A

-cylindrical, hollow structures made of gas-permeable protein
-some permeable to H2. N2, O2, CO2, CH4, and Ar
-small pore sizes exclude water
-makes Cyanobacteria buoyant

Lower density= higher buoyancy

By regulating their relative gas vesicles content, Cyanobacteria are able to migrate vertically

32
Q

Buoyancy cycle of Cyanobacteria

A
  1. Vesicles form under low light
  2. Cells migrate to surface
  3. Sugars accumulate
  4. Denser cells sink
  5. As nutrients are consumed, vesicles re-form
33
Q

Nitrogen fixing Cyanobacteria

A

Nitrogen fixation occurs only in prokaryotic bacteria and Cyanobacteria

Some symbiotic, some non-symbiotic

-the nitrogen didn’t enzyme, nitrogen are, is located inside heterocyst (specialized cells that perform N2 fixation (N2-NH+)

34
Q

During times of low environmental nitrogen, about ____ out of ____ cells in Cyanobacteria will differentiate into a ______

A

1
10
Heterocyst

35
Q

Intercalary heterocyst

A

In middle of trichome

36
Q

What colour are heterocyst

A

Pale

37
Q

Reaction of nitrogen fixation in Cyanobacteria

A

N2->NH4+->added to 2-oxoglutaerate (from citric acid cycle)->glutamate->NH4 added->glutamine (exported to vegetative cells)

Evolved in low O2 atmosphere-> unstable in presence of O2

38
Q

Protecting nitrogen are from O2 in Cyanobacteria

A

Heterocysts
-in filamentous Cyanobacteria
-physical protection from O2 with impermeable glycolipid layer, thick mucilage (polar plugs) reduce O2 diffusion from adjacent cells

Heterocysts
-biochemical protection from O2
-eliminate photo system 2 inside heterocyst (pale colour), no splitting of H2O to release O2
-cyanoglobin (from myoglobin) scavenges and binds O2
-higher respiration in cells bordering heterocyst

Diurnal cycle:
-found in groups of non-filamentous Cyanobacteria
-fix atmospheric nitrogen in the dark
-eliminate production of O2 by photosynthesis

39
Q

Vegetative cells fix ___

Heterocysts fix ____

A

C
N

40
Q

Why do Cyanobacteria need to be able to use a range of pigments

A

Have no appendages so they are carried with currents, so need to be able to use light at many depths

41
Q

Akinetes

A

Resting spores

Cells that are resistant to unfavourable environmental conditions

Surrounded by a wide, 3 layered coat and contain starch granules

42
Q

Akinetes are only produced by ______ that produce _____

A

Cyanobacteria

Heterocysts

43
Q

What physiological factors have been reported to stimulate akinete differentiation?

A

Nutrient deficiency, reduction in light (carbon limitation), reduced temperatures

44
Q

Floatation of akinetes is lost due to….

Floatation if akinetes occurs due to….

A

Accumulation of starch. Causing an Increase in density

Filaments with akinetes sink and overwinter in the bottom sediments

New filaments are produced by germination (gas vesicles re suspend new filaments)

45
Q

How do filamentous Cyanobacteria multiply?

A

-binary fission

-fragmentation: hormogonia short pieces of trichome that detach and travel by gliding and develop into new filaments.

Necridia create space and ends of hormogonia continue to increase length (isopolar)

46
Q

Necridia

A

Dead vegetative cells that weaken filaments and provide points where hormogonia separate

47
Q

Stromatolites

A

Diurnal (night vs day) cycle of growth (day) and sedimentations (night) resuming in laminations

In marine environments, Cyanobacteria deposit is result from trapping and binding of sediments as well as mineral precipitation

48
Q

Early earth atmosphere (early Proterozoic >2.5bya) contained mainly ______

A

Methane (CH4)

Insulates 22 times more effectively than CO2

This maintained high atmospheric temperatures

49
Q

Cyanobacteria began splitting H2O during photosynthesis when?

A

Late archean to early Proterozoic

2.8-2.2 bya

50
Q

O2 eliminated ____ by reacting to form CO2 and H2O

A

CH4

51
Q

Late archean to early protozoic history

A

2.8-2.2 bya
-first oceans and continents formed
-atmosphere rich in methane and nitrogen, no oxygen
-photosynthetic Cyanobacteria in oceans produce oxygen and transform atmosphere

Temps are warm

52
Q

Snowball earth history

A

650mya
-extreme ice age: glaciers reaching from the poles to the equator
-volcanos powered by tectonic plates, release carbon dioxide
-accumulating carbon dioxide increases global temperatures

-50°c average temp

53
Q

Cambrian history

A

500mya
-two main landmasses
-land barren, with some microbial communities
-marine life thrives in warm, oxygen-rich waters
-fossils of complex organisms: trilobites, mollusks, sea stars, sea urchins

Temp: warm

54
Q

Cryptogamic crusts

A

Cyanobacteria that Stabilize soil in arid systems

55
Q

Cyanelle

A

Intracellular, symbiotic Cyanobacteria that fixate nitrogen

Some occur in cells of marine diatoms

Coral colonies host coccinoid Cyanobacteria

In root of cycas sp

In water fern (azolla)

56
Q

Cyanobacteria and blooms

A

Natural, or anthropocentric pollution coupled to global climate changes, cause blooms

Phosphate levels rise, n it riven becomes limiting

Cyanobacteria fix their own nitrogen and become dominant over other organisms and other algae decline

57
Q

Release of O2 by Cyanobacteria caused temperatures to _____

A

Reduce (snowball effect)

58
Q

Cyanotoxins

A

Cyanobacteria defence against invertebrate herbivores

Include: neurotoxins and hepatotoxins

59
Q

Neurotoxins

A

Alkaloids, block neuron transmission to muscles leading to staggering, muscle twitching, gasping, convulsions, and death caused by respiratory arrest

Ex: anatoxin (Anabaena, Oscillatoria)

60
Q

Hepatotoxins

A

Inhibitaors of phosphatases in liver resulting in internal bleeding, weakness, vomiting, diarrhea, cold extremities

Ex: microcystin (microcystis, Anabaena, Nostoc, Oscillatoria)

61
Q

Microcystis blooms cause what illness

A

Dugout death

Livestock and domesticated animals are poisoned by drinking contaminated water, fish and bird mortalities also reported in water bodies with these blooms.

Algae, Fungi And Mosses (18 decks)

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