Bio Exam II.1 Plasmodial and Cellular Slime Molds
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Why are they called plasmodial?
the vegetative portion is a sheet of protoplasm (often fan-shaped and different colors)
Explain plasmodial slime molds.
(-walls? type of cell? nucleus? movement?)
-no cell wall, but there is a plasma membrane
-eukaryotic cell; has nuclei (the size of the slime mold determines the amount of nuclei)
-creeps like an amoeba (moves in one direction)
How do they appear?
Explain the cytoplasm.
Explain movement of some.
they appear to have veins going through them; called veins
in some, moves in one direction, stops, and moves in another direction
What is the advantage of the movement of moving in one direction and then another?
- mixing chemicals
- - they feed on things similarly to amoebas. As it is broken down, cytoplasmic streaming helps distribute it.
- - synchronous dividing of nuclei
Where do they live?
in the soil, leaf litter
they really don't like light; not really seen on the surface of the their habitat, but may come out at night
As long as there is good temperature, the conditions are favorable, and there is water, they grow and live
What are bad conditions for plasmodial slime molds?
What do they do?
if food is short and the plasmodium dries out, the temperature is incorrect
The plasmodium forms clumps--> forms sporangia to ensure that the organism survives
The nuclei in plasmodium is __. How?
- through meiosis--> haploid spores
Explain the spores?
- has plasmodial cell walls--> germinates to amoeba-like cells (mixamoebas or flagellated swarm cells)
- - can be either depending on the presence of water
- water= flagellated
- lack of water= unflagellated
What do these spores act like?
- they act like gametes/ cells pair up and fuse
- can also do mitosis to build a population
Cytoplasmic fusion= __
nuclear fusion= __
There is no __ leading to __.
- a multinucleate structure
What are the parts of the sorocarp?
the sorus (group of spores)
the sorophore (stalk)
A whole bunch of cells in __ can do what?
round up and secrete cell wall made of cellulose
What is the life cycle of a cellular slime mold
sorocarp--> forms spores ---germination
--> myxamoebae (vegetative state)--> a or b
- a: microcyst (altermate)
- b: aggregation--> c or d
d--> formation of psudoplasmodium--> pseudoplasmodium--> sorocarp
In terms of nuclei, what are myxamoebae?
What state are they?
How can macrocyst turn into myxamoebae?
In aggregation, what are the cells doing?
In a macrocyst, what can happen?
whole bunch of cells that stream to the center of the cell, where it is the most dense
moving toward the most dense region
some cells get confused and carry out meiosis
Once they reach a particular density, what happens?
Once they reach a particular density, there is release of acrasin (cAMP), which is released in pulses that diffuse out to the population
Where is cAMP mostly? Explain.
more cAMP in the center; pauses; releases its own cells; move when pulses are released
From aggregation--> __
The length of the center is __.
What do the cells start doing?
It becomes a __, acting as a __.
formation of psedoplasmodium
1 mm long
cells start specializing and adhering to one another
acts as a multicellular organism
Formation of pseudoplasmodium--> __
What is happening?
the cells are no longer dividing at this point; it is around 1 mm long
From the pseudoplasmodium--> __.
sorocarp (haploid cells)
__ does not occur in sorocarp development. What is here is a way of __.
way of distributing cells
What is the economic importance?
can be classified as decomposers
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