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Heterokontophyta Flashcards

1
Q

Golden algae taxonomy

A

Phylum Heterkontophyta
Class chysophyceae

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2
Q

Phylum Heterokontophyta have what type of endosymbiosis

A

Secondary with red algae

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3
Q

Habitat of Chrysophyceae

A

Oligotropic (low nutrient) fresh water environments

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4
Q

Feeding of Chrysophyceae

A

-facultatively heterotrophic (mixotrophy) in absence of adequate light, or plentiful, dissolved food
-eat yeast, smaller eukaryotic algae, and starch grains, bacteria
-in low light, 80% of carbon from phagotrophic activity

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5
Q

Heterokont meaning

A

2 flagella
-tinsel (anterior)
-whiplash

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6
Q

Cysts of Chrysophyceae

A

Stomatocysts
-preserved in fossil record
-silica shell
-~100mya (Cretaceous)
-161 distinctive morphological stomatocysts identified in arctic peat

-cyst wall inside membrane
-silica deposits within coalesced golgi vesicles
-pore at apex plugged with polysaccharide

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7
Q

What type of rock can you find fossilized stomatocysts

A

Pyrite

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8
Q

Why are ancient fossils of stomatocysts found in marine environments but the class is freshwater?

A

Probably in ocean water, and estuary type of environment transported them to fresh water to be fossilized

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9
Q

Chrysophyceae pigments

A

-chlorophyll’s a, C1 and C2
-chlorophyll c is for photo system 2
-accessory and protective pigment: fucoxanthin (carotenoid) that gives golden colour

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10
Q

B-1,2 glucan, found in posterior vesicle

A

Chyrosolaminarin

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11
Q

Photosynthate and storage organelle of Chrysophyceae

A

Pyrenoids

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12
Q

Chrysophyceae mobility

A

-flagellar swelling contains electron-dense area called a photoreceptor
-eyespot under flagellar swelling inside the chloroplast

-tinsel and whiplash

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13
Q

Cell walls of Chrysophyceae are composed of

A

Cellulose, Loricas and silicified scales and walls

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14
Q

Lorica

A

Envelope of microfibrils around protoplast
-not generally attached to protoplast

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15
Q

Chrysophyceae reproduction

A

-isogametes structurally similar to vegetative cells
-zygotic meiosis
-female produce a pheromone to attract males flagellated cells to swim to female
-resulting zygote becomes a stomatocyst and loses its flagella

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16
Q

Stomatocysts can result from _______

A

Asexual or sexual reproduction and are indistinguishable

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17
Q

Freshwater ________ are commonly used as in dictators of the environmental conditions during the deposition of the sediments

A

Stomatocysts

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18
Q

How do Chrysophyceae indicate environmental conditions?

A

-Indicate low levels of pollution
-high phosphate decreases populations
-prefer low pH related to their acid phosphatase enzymes that liberate phosphate from organic compounds and give advantage in low nutrient areas
-seasonal cold and oligotrophic conditions protect from predation

Fires give more nutrients so less Chrysophyceae

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19
Q

Class Bacillariophyceae are known commonly as….

A

Diatoms

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20
Q

Diatoms habitat and feeding

A

-almost every aquatic habitat as free-living photoautotrophs, colourless heterotrophs or photosynthetic symbiotes

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21
Q

Most numerous aquatic eukaryotes are

A

Diatoms

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22
Q

Most important aquatic primary producers are

A

Diatoms (25% of global PP)

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23
Q

Diatoms habitat

A

-dominant in cold, nutrient rich waters (ocean upwellings) and circulated waters of fresh water lakes

-planktonic, benthic, periphytic, endozpic (in animal) or ectozoic (on animal)

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24
Q

Diatom Frustules

A

-contain 96.5% silica oxide

-Frustules are enveloped by organic skin of amino acids and sugars
-bio-silica structure have increased strength because of their organic-inorganic microstructure
-silica walls accumulate in sediment (bio indicator)

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25
What makes up a frustule
-epivalve+ epicingulum = epitheca -hypovalve+hypocingulum= hypotheca Epitheca+hypotheca= frustrule
26
Diatoms are divided into two major groups based on valve symmetry:
Radial symmetry-centric diatoms Bilateral symmetry-pennate diatoms
27
________ are relatively young among photosynthetic eukaryotes Earliest known fossil is from _____
Diatoms Early Cretaceous (150mya)
28
Continuous record of diatom fossils in marine sediments date to
65mya Increasing evolution of genera and species since Paleozoic
29
Diatoms chloroplasts and pigments
-cells contain two (Pennales) or many (Centrales) chloroplasts -central Pyrenoid (starch synthesis and storage) -chloroplasts surrounded by two membranes of chloroplast envelope and two membranes of chloroplast endoplasmic reticulum -chlorophyll a and c1 and c2 and fucoxanthin (carotenoid) -Chrysolaminarian (storage molecules in vesicles)
30
Important of silica to diatoms
-silica created a physically strong and chemically inert, protective covering since frustules resists enzymes -predators have to crush diatoms or slip between wall components -silica uptake by diatoms requires less energy than required to create an organic wall
31
Advantages of silica covering
-silica in minerals form rocks-> replenished from sand and silt -physically strong and chemically inert, protective covering -requires less energy than creating an organic cell wall
32
Disadvantages of silica covering
-impermeable which limits diffusion of nutrients and waste products -silica does not stretch to accommodate cell growth
33
Dissolved ______ determines diatom abundance
Silica -spring pulses of diatoms deplete silica in temperate lakes -autosomal mixing creates second pulse of diatoms Silica accumulates in winter
34
How can diatoms grow or reproduce if silica covering is fixed?
Control over cell turgor allows protoplasts to push the thecae apart to grow and release gametes Growth of each theca is accomplished by the addition of a series of girdle band to the edge of the valve
35
Asexual reproduction of diatoms
-requires the formation of one new valve for each daughter cell -new valves are slightly smaller than those of the parent -average size of cells in a population shrinks over many generations -gametes produced when a diatom cell reaches a minimum size:45-55% or up to 75% of their maximum size (3 years)
36
Sexual Alice cycle of diatoms
Gametic= diploid generation is dominant and gametes are the only haploid stage Centric diatoms: male gametes are motile (single tinsel flagella) Pennate diatoms: both gametes are non-flagellated Auxospores: formed by the fusion of two gametes and re-established original size of cells
37
What is the only flagellated cell found in diatoms at any stage of life cycle
Centrales make gamete
38
Resting spore of diatoms
Formed by a frustules producing two more layers of valves inside the outside frustules Layer of mucilage is secreted to the outside enables a prolonged resting period
39
Silica frustules are more dense than sea-water? What can help them float?
Vacuoles with lipids Longer shape for more surface area Perforated silica to allow for air Accumulating less silica
40
Raphe
Slit running the length of the valve to expose cell membrane to a solid surface in pennate diatoms
41
Motility of diatoms
Rapid “gliding motility” on a solid surface, excreting a mucilaginous propellant. (Raphe in Pennales) Few centric diatoms have slower “shuffling motility”
42
Carbon fixed by sea ice ______ is exploited directly by zooplankton and krill which are then BC insured by whales, seals and birds and fish
Diatoms Food web member Sea ice algae found in coastal polynyas-areas of open water or thin ice within thicker pack ice
43
Diatom human uses
-silica frustules of diatoms have accumulated in ocean sediments over millions of years, forming the find crumbly substance known as diatomaceous earth -scouring element in cleaning products, ultra find filtration for purification of water, natural pesticide, crime investigation building blocks and bricks (low density but strong and heat insulation properties-diatomite blocks)
44
Class Phaeophyceae are known as what
Brown algae
45
Endosymbiosis of Phaeophyceae
-Secondary endosymbiosis with red algae -Plastids surrounded by 4 membranes (2 form cyano, 2 from E.R of eukaryote)
46
Diversity of Phaeophyceae
-Microscopic filaments to giant kelp -MARINE, but 4 genera in freshwater. Can penetrate brackish water
47
Habitat of Phaeophyceae
-dominant intertidal to shallow sub-tidal region of littoral zone (<60m) -important shallow water habitat for fish and invertebrates -Dominant colder waters (NH)=epilithic -Huge concentration in saragasso sea =pelagic
48
Tiny Brown algae
Micro-browns Freshwater living, often encrusted with marl (CaCO3)
49
Cell structure of brown algae is similar to _______ and ________. The main difference is…..
Chrysophyceae Bacillariophyceae Amounts of extracellular polysaccharides surrounding the protoplasts.
50
Cell walls of brown algae components
Cellulose (structural support) Alginic acid (flexibility and prevent dedication since tidal habitat) Fuchs polysaccharides (anchor)
51
Storage products from photosynthesis in Brown algae
-Sugars -Sugar alcohol (D-mannitol) which makes up 25% of dry weight of Laminaria sp. -Low molecule weight compounds (glycerol and mannitol) lower freezing point of cytoplasm
52
Mannitol has osmoregulation
Mannitol concentration changes with salinity of the surrounding medium-> prevents cells from bursting in hypotonic media or shrinking in hypertonic media
53
Filamentous growth of brown algae Kelp growth of brow algae
Cell division among a single plant of division Meristems cells: -Basal meristem: early growth to extend height -Intercalary meristem: mature growth to extend height -meristoderm: increases girth
54
Laminariales anatomy of blade
Blade composed of three basic structures 1. Epidermis: outermost layer of tissue consisting of small epidermal or palisade cells 2. Dermal tissue (cortex) below epidermis is differentiated into ectodermal tissue and endodermal tissue 3. Pith (medulla) composed of two types of cells: pith and trumpet cells
55
Trumpet cells
Laminaria sp. Form network of conducting cells -end walls have perforated sieve plates -network of trumpet cells transport photosynthates (mannitol) like a vascular system of higher plants
56
Sargasso Sea has what type of seaweed? What is its importance?
Floating seaweed belonging to brown algae known as saragassum Supports a diverse community of organisms
57
American eel and the Sargasso Sea
-life cycle of eek begins in open ocean (Sargasso Sea) where eel larva hatch. -larvae carried in ocean current and change into more elongated eels and migrate to rivers, streams and lakes. -grow into yellow eels (immature); adults migrate back to Sargasso Sea
58
Economic uses for Brown algae
-kelp harvested for mineral (is online and NaCO3) and organic Alvin are content as well as directly for food -iodine to treat goiters -NaCO3 used for glass and soap -Alginate are used to thicken ice cream, jelly, tooth paste and salad dressing, make teeth impressions, treat heartburn
59
Harvesting kelp
-scraping off rocks (traditional) -since the blades grown from Intercalary meristem (from bottom to top) the top couple of meters can be cutoff and the plants will continue to grow
60
Kelp aquaculture
-Kelp sporophytes can be grown on ropes suspended in large racks for easy harvest

Algae, Fungi And Mosses (18 decks)

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