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Algae, Fungi And Mosses > Dinophyta > Flashcards

Dinophyta Flashcards

1
Q

_____% of dinoflagellates are planktonic

A

90

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2
Q

Dinoflagellates are included in the group ________

Why?

A

Alveolates

Presence of alveoli (membrane bound vehicle)

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3
Q

Cell covering a of dinoflagellates

A

Continuous outermost membrane + single membranes bound thecal vesicles (alveoli)

Thecal vesicles contain little or no cellulose or thick cellulose plates (thecal plates)

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4
Q

Amphiesma

A

Array of membranes and vesicles

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5
Q

Dinoflagellate cell types distinguished by position of flagella:

A

Desmokont: flagella emerge apex
-both flagella inserted anteriorly

Dinokont: flagella emerge from mid point (ventrally inserted)
-both flagella are inserted centrally and lie in surficial grooves (whiplash and tinsel flagella)

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6
Q

Typical dinokont cell types

A

Upper half: Epicone
Lower half: Hypocone

Transverse groove-encircles the cell: girdle

Sulcus: extends posteriorly in the hypocone from the cingulum

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7
Q

Part of cell directed forward during swimming is considered to be ______

A

Anterior

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8
Q

Region from which flagella emerge is considered _____

A

Ventral side

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9
Q

Dinophyta vary in the number and arrangement of ______

A

Thecal plates

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10
Q

Controversy of thecal plate arrangement

A

Was many thecal plates original to ancestor or was few???

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11
Q

Dinoflagellates originated from ______ ancestors

Why is this supported

A

Heterotrophic (800mya)

Many dinoflagellates are heterotrophic today

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12
Q

In the fossil record, _____% of dinoflagellates produce an organic layer of _______ beneath thecal plates

A

40

Dinosporin

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13
Q

____% of dinoflagellates are __________
But most are _______

A

Photosynthetic (50%)

Mixitrophic

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14
Q

Most photosynthetic dinoflagellates originated from _____ symbiosis with a ______ and therefore contain ______

A

Secondary
Red algae

Chlorophyll a and c as well as peridinin (carotenoid) and pyrenoids

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15
Q

Plastid membranes of dinoflagellates

A

Two membranes of chloroplast envelope

One membrane of chloroplast e.r from primary host ebdosymbiont

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16
Q

Tertiary endosymbiosis in dinoflagellates

A
  1. Begins with a loss of a Plastid (originally deceived from a secondary endosymbiosis of red algae)
  2. Followed by endosymbiosis of a diatom
  3. Instead of peridinin pigment it has fucoxanthin pigments from diatom
17
Q

In Dinophyta, photosynthates are stored as _____

A

Cytoplasmic starch grains, lipids droplets, unsaturated fatty acids and sterols

18
Q

Some dinoflagellate sterols are linked to fossil _______

A

Oil deposits

Blooms contributed to oil deposits in areas with incomplete degradation of organic lipids

19
Q

In a dinoflagellate, where can you find lipid bodies and starch grains

A

Lipid-anterior end of cell

Starch-posterior end of cell

20
Q

Chromatic adaption

A

Dinophyta are able to capture and harvest more light by using water soluble peridinin-chlorophyll-protein light harvesting complex (PerCP) found in the lumen of plastids and membrane bound light harvesting complexes

Peridin absorbs in the blue-green range (450-550) which is beyond chlorophyll-A’s capability

More peridinin to chlorophyll is chromatic adaptation

21
Q

Dinophyta motility

A

-longitudinal flagellum (whiplash) projects out->speed and steeering

-transverse flagellum (tinsel) coiled and closest appressed and used for rotating

Great swimmers (200-500mm/sec)

22
Q

How are the flagellum arranged in dinophyta

A

9+2 array of microtubules

23
Q

What percent of dinoflagellates have an eyespot?
What does the eyespot do?

A

<5%

They are simple: lipid droplets packaged within membranes
Or
They are complex: rows of lipid globules

Contain carotenoids for phototaxis
-reposition longitudinal flagellum and swim towards light

24
Q

Do dinophyta have a flavin based light detector at the base of the flagella?

A

No

25
Q

Dinophyta Trichocysts

A

-defensive trichocysts: rod shaped crystalline, protein filaments
-triggered by changes in temperature, turbulence, and other disturbance
-discharged upon rapid hydration
-discharge causes a jet-propulsive response to predators

Or can be used to catch prey (nematocysts)

26
Q

Dinophyta reproduction

A

Asexual division of haploid, motile cells

Sexual reproduction due to changes in nutrients, irradiance, photoperiod, temp
-gametes resemble vegetative cells, syngamy is slow and difficult to distinguish from cell division, and often occurs at night. Making it hard to observe!!!!

-early stages of zygote development have >2 flagella

-formation of cysts often follow sexual reproduction and are viable for 100 years

27
Q

Photosynthetic _______ are second to diatoms as primary producers in costal waters

A

Dinoflagellates

28
Q

Zooxanthellae

A

Unarmoured marine dinoflagellates are marine symbionts of most reef bulking coral polyps

29
Q

“Bleaching”

A

When coral polyps expel their zooxanthellae and therefore their colour

30
Q

Zooxanthellae and coral exchange of nutrients

A

Coral gets plenty of carbon from zooxanthellae

Zooxanthellae get carbon dioxide from coral

31
Q

Dinoflagellates were once called what?

Why?

A

Pyrrhophyta (fire plants)

Some species are bioluminescent

32
Q

Adaptation to bioluminescence

A

Reduce attack by predators by shocking predators

33
Q

How does bioluminescence work

A

Scintillons: spherical intracellular structures derived from invaginations of vacuole membranes that contain luceiferin (chlorophyll-derived molecule)

Luciferase oxidizes luciferin, causing a flash of blue light

Circadian rhythm in synthesis and destruction of scintillons: night phase (540 scintillons per cell) vs day phase (46/cell)

34
Q

Red tides

A

Surface upwellings of nutrients trigger blooms of photosynthetic dinoflagellates
-some species in blooms produce neurotoxins-> paralytic shellfish poisoning

35
Q

Saxitoxins

A

Block Na+ movement through voltage-dependent channels in nerve and muscle cell membranes=prevent action potentials

-dinoflagellates that produce toxins contain chloroplasts: ability to produce toxins drives from endosymbiotic Cyanobacteria

36
Q

Pfiesteria sp

A

Predatory dinoflagellate common in estuaries
-kill fish by feeding on their skin (large lesions)
-dinoflagellate zoospores feed on the fish by phagocytizing fish tissue through peduncle.
- the peduncle is swollen with haustoria/like penetrating extensions when feeding on the fish

Algae, Fungi And Mosses (18 decks)

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