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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
Photo acclimation
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
Photo acclimation in polar area
Relatively constant photosynthesis of polar phytoplankton appear to be a response to the persistently low, yet continuous irradiance of the polar summer.
27
When are photosynthetic pigments highest
Peak in morning, lower in evening
28
Cyanobacteria swimming
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
Motor cargo proteins
Move along a continuous looped helical track creating distortions Protein that moves Cyanobacteria
30
Oscillation
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
Gas vesicles in Cyanobacteria
-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
Buoyancy cycle of Cyanobacteria
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
Nitrogen fixing Cyanobacteria
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
During times of low environmental nitrogen, about ____ out of ____ cells in Cyanobacteria will differentiate into a ______
1 10 Heterocyst
35
Intercalary heterocyst
In middle of trichome
36
What colour are heterocyst
Pale
37
Reaction of nitrogen fixation in Cyanobacteria
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
Protecting nitrogen are from O2 in Cyanobacteria
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
Vegetative cells fix ___ Heterocysts fix ____
C N
40
Why do Cyanobacteria need to be able to use a range of pigments
Have no appendages so they are carried with currents, so need to be able to use light at many depths
41
Akinetes
Resting spores Cells that are resistant to unfavourable environmental conditions Surrounded by a wide, 3 layered coat and contain starch granules
42
Akinetes are only produced by ______ that produce _____
Cyanobacteria Heterocysts
43
What physiological factors have been reported to stimulate akinete differentiation?
Nutrient deficiency, reduction in light (carbon limitation), reduced temperatures
44
Floatation of akinetes is lost due to…. Floatation if akinetes occurs due to….
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
How do filamentous Cyanobacteria multiply?
-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
Necridia
Dead vegetative cells that weaken filaments and provide points where hormogonia separate
47
Stromatolites
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
Early earth atmosphere (early Proterozoic >2.5bya) contained mainly ______
Methane (CH4) Insulates 22 times more effectively than CO2 This maintained high atmospheric temperatures
49
Cyanobacteria began splitting H2O during photosynthesis when?
Late archean to early Proterozoic 2.8-2.2 bya
50
O2 eliminated ____ by reacting to form CO2 and H2O
CH4
51
Late archean to early protozoic history
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
Snowball earth history
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
Cambrian history
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
Cryptogamic crusts
Cyanobacteria that Stabilize soil in arid systems
55
Cyanelle
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
Cyanobacteria and blooms
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
Release of O2 by Cyanobacteria caused temperatures to _____
Reduce (snowball effect)
58
Cyanotoxins
Cyanobacteria defence against invertebrate herbivores Include: neurotoxins and hepatotoxins
59
Neurotoxins
Alkaloids, block neuron transmission to muscles leading to staggering, muscle twitching, gasping, convulsions, and death caused by respiratory arrest Ex: anatoxin (Anabaena, Oscillatoria)
60
Hepatotoxins
Inhibitaors of phosphatases in liver resulting in internal bleeding, weakness, vomiting, diarrhea, cold extremities Ex: microcystin (microcystis, Anabaena, Nostoc, Oscillatoria)
61
Microcystis blooms cause what illness
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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