Protozoans-Amoeba
Terms
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- What phylum do amoebae belong to?
- -Phylum Sarcodina
- Where do you find Amoeba P.?
- -freshwater on bottom debris
- What is plasmalemma?
- -the cell membrane that bounds amoeba
- What are/is pseudopodia/lobopodia?
-
-blunt projections on amoeba
-for movement and feeding - List the organelles found in amoeba.
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-ectoplasm
-endoplasm
-nucleus
-food vacuoles
-mitochondria
-crystals
-contractile vacuoles - How do amoeba move?
-
-by cytoplasmic streaming. Forms pseudopodia
-ectoplasm appears stationary, endoplasm moves. - What is a Hyaline cap?
-
-found in amoeba
-clear fluid continually forming at the distal end of the pseudopodium - What is the uroid?
- -the region that refers to the posterior end of the amoeba that crumples due to the forward movement
- What is plasmagel?
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-found in amoeba
-the rigid gel-like cytoplasm that makes up the ectoplasm - What is plasmasol?
-
-found in amoeba
-makes up the endoplasm, loose flowing - How do amoeba feed?
-
-forms food cups with the pseudopodia
-engulfs the food to form a food vacoule - How do amoeba digest?
-
-lysosomes fuse with the food vacoules to delvier digestive enzymes
-vacuoles may subdivide into several smaller vacuoles to increases surface area - How do amoeba get rid of waste?
- -reverse phagocytosis
- How do cells within an amoeba distribute nutrients?
- -by cytoplasmic streaming
- What is the function of the contractile vacuole?
- -it is the main organelle of osmoregulation
- What are the 4 amoeba movement theories?
-
1)Pressure Theory
2)Front Contraction Theory
3)Gel-endoplasm Shearing Theory
4)Movement involving actin Theory - What does the Pressure Theory of amoeboid movement suggest?
- -contraction of the ectoplasm near the posterior end of the amoeba squeezes the endoplasm forward to form pseudopodia
- What does the Front Contraction Theory of amoeboid movement suggest?
-
-suggests that endoplasm is not a homogeneous sol, there is a core of gel in the centre of the amoeba
-the core can contract in the region where the amoeba is going to form a pseudopodium
-squeezes out water to form the hyaline cap
-contraction pulls the whole core forward therefor collapsing the rear - What does the Gel-endoplas Shearing Theory of amoeboid movement suggest?
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-accepts most components of front contraction theory
-further suggests that a ratchet mechanism at the interface of the gel core and gel tube is responsible for moving the core gel past the peripheral gel - What does the Actin Involved Theory of amoeboid movement suggest?
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-actin is present in the ectoplasm
-supports the sides of the developing pseudopods
-actin disassembles nears the tip of the pseudopodium, causing a concentration gradient, therefor pulling water into the pseudopodium
-actin is then reformed and cycle continues - List the characteristics of Pelomyxa carolinensis.
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-larger than amoeba proteus
-multinucleate
-has fewer but more blunt pseudopodia than Amoeba proteus - List the characteristics of Entamoeba gingivalis.
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-lives on the gum tissues of man
-very small
-pseudopodia are very short and blunt - List the characteristics of Entamoeba histolytica.
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-lives in the intestines of humans
-eats bacteria in the intestine, may eat into intestinal walls
-always reproduces asexually, done in 2 ways
1)binary fission
2)cyst formation
-cyst is passed in feces and ill infect a new host if ingested -
What are the two testate forms of amoeba that are closely related to the naked amoeba?
What order do they belong to? -
1)Arcella - Chitinous domeshaped test with round opening at bottome
2)Difflugia - test made of mineral particles ingest and then embedded in a secreted matrix
**Belong to Order Testacea** - Is Arcella binucleate, uninucleate or polynucleate?
- -All of them
- What is the main characteristic of the Order Foraminifera?
- -secretes calcium carbonate shells consisting of a single or multiple chambers
- What is multilocular?
- -term for many chambered shells
- What is reticulopodia?
-
-long, slender, trhread-like branched and interconnected pseudopodia of Foraminireans
-important in movement, secreting the shell and trapping food organisms - What is actinopodia?
- -pseudopodia with internal skeletons of microtubules
- What are radiolarians?
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-marine organisms that secrete complicated siliceous skeletons composed of concentric hollow balls connected by radiating rods which continue outward as spines
-has a central capsule which separates the cell into intra and extra capsular regions - What are Heliozoans?
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-have actinopodia like radiolarians but don't have a central capsule
-everything else is like radiolarians(ie: food capture etc.)