Amoeba (plural amoebas/amoebae) is a genus thatbelongs to Kingdom protozoa. Generally, the term is provided to describesingle celled biology that relocate in a primitive crawling manner (by usingtemporary "false feet" recognized as pseudopods).
Amoebas room eukaryotes,which way that their genetic material room well organized and enclosed withina membrane (nuclear membrane)
* The word amoeba originates from the Greek word"amoibe" which means to change
Amoebas room simply solitary celled organisms. Assuch, they have the right to only be viewed using a microscope. Over there are techniques that deserve to beused to observe these organisms.
The first and simplest methods requires viewing amoebas under the microscopic lense without staining. This is a simple methodthat enables students to view them live together they move around. The secondmethod requires fixing and staining to gain a much better view of thestructure and organelles of the organism.
You are watching: Using a microscope, you observe an amoeba moving toward a food source. this is an example of
1. Straightforward (Direct) method
Amoebas have the right to be found freely living and also thrivingin shallow pond waters with organic material.
To check out amoebas under themicroscope, students will need the following:
A sample that water collectedfrom a pond v organic materialPondweed native a pondPetri food WaterA dropper
For this technique, the student might eitherobserve a sample the pond water directly to determine the biology orconduct a simple culture to grow and also increase the variety of amoebas.
Amoebaculture is a straightforward exercise that involves the following few steps:
Place a couple of pondweeds in a petri-dishand include some water come cover the weedLeave the society is a darkroom because that a few days and also wait till a brown scum creates on the surface
Procedure for Microscopy
Gently covering the samplewith a cover slip and mount ~ above the microscopic lense stage for viewingStart through low power andincrease slowly to observe the specimen
When viewed, amoebas will appear like a colorless(transparent) jelly moving across the field very slowly together they changeshape. Together it changes its shape, it will certainly be watched protruding long, fingerlike projections (drawn and withdrawn).
2. Fixing and Staining technique
Amoeba cultureNeff"s saline, sea waterMoist chamberCover slipSodium hydroxide (NaOH)Distilled water Nissenbaum"s fixativeLugol"s IodineFormalin seawater Carnoy"s fixativeHeidenhain’s ironHaematoxylin
For this technique, the specimen (amoebae) isfirst cultured making use of such culture and saline agar slopes. Adhering to theculture, a sample of the specimen is further focused using a centrifuge(at 3 Krpm for about 10 minutes).
This is continued by the following few steps:
Wash the pellet making use of 75 percent seawater,Neff"s saline or any type of other suitable solution enable the specimen to resolve on a cover slip ina moist chamber till the amoebae adopt a typical locomotionary morphology (the coverslip can be treated with sodium hydroxide depending on the type of amoeba)
While settling on the coverslip, pipette freshly prepared Nissenbaum’s Fixative on the sample and permit tostand for 5 minutesWash the sample withacidified HgCl2 for about 7 minutesWash the sample through 50%,35%, 15% ethanol for around 5 minutesWash the sample again withdistilled water for about 5 minutes
Some that the various other fixatives that have the right to be usedinclude:
Carnoy’s FixativeLugol’s IodineSeawater formalin
Staining the amoebae is aimed in ~ enhancingvisibility the the mitotic figures.
Some of the stains that can be offered to stainthe amoeba cell include:
Heidenhain’s ironHaematoxylinKernechtrot (Nuclear Red)Modified Field’s StainKlein’s silver relief stain
For Heidenhain’s stole Haematoxylin, staininginvolves the following steps:
Inoculation of the samplein 2 percent ammonium ferric sulphate for around 1 and a half hourRinsing the sample in distilledwaterInoculation of the samplein 0.5% haematoxylin and 2% ammonium ferric sulphate for around one and a halfhours wash the sample with tapwater
After staining, mount the on slide on themicroscope stage to observe.
When regarded under the microscope, college student willnotice small dark clues in the cytoplasm the the biology while the cytoplasm islightly stained.
* Direct monitoring of the organism (without staining) has actually a greatadvantage in that the amoebae are still alive and motile as soon as being viewedunder the microscope.
This permits the students to see the finger likeprojections (pseudopods) elongate and also shorten together the biology moves around orengulfs provided substrates. However, this method does not enable students toview the cell’s organelles.
Fixing and also staining on the other hand kills theamoeba, which means that students will certainly not acquire to watch the organism relocating inthe field of view but stainingincreases contrast, allowing students to obtain a much better view the the oribelles inthe cell.
Structure that Amoeba
As mentioned, amoebae room eukaryotes, i beg your pardon simplymeans the they have a cabinet membrane neighboring their cytoplasm and DNA thatis properly packed in the main nucleus.
When regarded under the microscope,these aspects of the organism are clearly visible particularly when the sampleis stained.
Some that the various other organelles that are visible under the microscopeinclude:
A food vacuoleContractile vacuole
* v regards to your structure, amoebaeclosely resemble cell of higher animals prefer those of human being beings.
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Essentially, Pseudopodia are temporaryprojections that the cytoplasm that make it feasible for amoebae to move.Pseudopods are few of the most distinguishable attributes of amoebae and also theirformation is based on the circulation of the protoplasm.
The organism contractsin a manner that pushes the cytoplasm come fill and expand a pseudopod if pulling at adhesions in ~ the ago of the cell.
According come studies, the processinvolves the following steps:
With pressure from ectoplasm, i m sorry is anexterior gel, endoplasm (interior fluid) is forced to circulation forwards in the cell.On getting to the reminder of the membrane, thepressure causes the endoplasm to type a pseudopod.The endoplasm is climate forced back towards theectoplasm and also turns to gelatin (this reasons the new pseudopod to disappear) The newgel is again converted to endoplasm and also again under pressure moves come themembrane to kind a brand-new pseudopod.
Apart from using pseudopod to relocate around,amoebae also use them to engulf food particles. Here, the pseudopod surroundthe fragment while an opened on the membrane permits the particle to relocate intothe cell and into a food vacuole wherein it is digested by enzymes.