external structure of paramecium

www.nepeducation.com Abhay Mishra

Paramecium Kingdom – Animalia

Phylum – Protozoa

Sub-Phylum – Ciliophora

Class – Ciliata or Infusoria

Sub-Class – Holotricha

Order – Hymenostomatida

Sub-Order

Family –

Genus

Introduction: -

Paramecia are minute organisms just visible to the naked eyes as elongated whitish or grayish spots. It differes from Amoeba in having a permanent body shape.

History: -

The name “Chausson” given to means slipper shaped animal. The generic name “Paramecium” (Gr. Paramekos – Oblong) given by John Hill in 1752.

Habit & Habitat: -

Paramecium is perhaps the commonest ciliate found everywhere in freshwater i.e. ponds, pools, ditches, river, lak


Paramecium

Ciliophora

Ciliata or Infusoria

Holotricha

Hymenostomatida

Order – Peniculina

– Paramecidae

Genus – Paramecium

minute organisms just visible to the naked eyes as elongated whitish or grayish spots. It differes from Amoeba in having a

The name “Chausson” given to Paramecium Caudatum by Joblot means slipper shaped animal. The generic name “Paramecium” (Gr.

Oblong) given by John Hill in 1752.

is perhaps the commonest ciliate found everywhere in freshwater i.e. ponds, pools, ditches, river, lakes etc. It is specially


minute organisms just visible to the naked eyes as elongated whitish or grayish spots. It differes from Amoeba in having a

by Joblot means slipper shaped animal. The generic name “Paramecium” (Gr.

is perhaps the commonest ciliate found everywhere in es etc. It is specially


abundant in organic infusions i.e. in stagnant water containing decaying organic matter feeding upon the bacteria & tiny protozoa that swam in such water. It is free living & found float on the water surface.

External Feature: -

Shape & Size: -

Under microscope it looks rather elongated and cigar shaped or slipper shaped & hence called slipper animalcule.

It is 180 &m – 300 &m long & 45.75 P.Caudatum 170 – 290 &m]

· The anterior end is broad & rounded while the posterior end is more or less pointed.


abundant in organic infusions i.e. in stagnant water containing decaying organic matter feeding upon the bacteria & tiny protozoa that swam in such water. It is free living & found float on the water surface.

Under microscope it looks rather elongated and cigar shaped or slipper shaped & hence called slipper animalcule.

m long & 45.75 &m wide [Largest species

end is broad & rounded while the posterior end is more


abundant in organic infusions i.e. in stagnant water containing decaying organic matter feeding upon the bacteria & tiny protozoa that swam in

Under microscope it looks rather elongated and cigar shaped or

m wide [Largest species

end is broad & rounded while the posterior end is more


· The upper dorsal or aboral surface is convey while the ventral or oral surface is concave & thicker.

· It has greatest diameter just behind the centre of the body.· The ventral surface sh

oral groove which posteriorly leads to a deeper conical vestibule which in turn communicates with a buccal cavity having a basal mouth or hypostome.

· The ectoplasm secretes or colorless, thin, firm, elastic & cutmembrane which covered the body is called pellicle or, periplast which is responsible for a definite & constant shape of the paramecium.

· The surface of pellicle has a great number of polygonal or hexagonal areas bearing the opening of trichocyst.

· Each hexagonal areas has a central depression or circum ciliary space from which a cilium comes out.

· All cilia are equal in size except those of the posterior end which are longer and called caudal tuft.

· The cilia originate from the basal granules or kinet12 & in length and 0.27

Internal Structure: -

The cytoplasm beneath the pellicle is clearly differentiated into two regions i.e. outer ectoplasm or cortex &medulla.


The upper dorsal or aboral surface is convey while the ventral or oral surface is concave & thicker. It has greatest diameter just behind the centre of the body.The ventral surface shows a large shallow oblique depression, the oral groove which posteriorly leads to a deeper conical vestibule which in turn communicates with a buccal cavity having a basal mouth or hypostome. The ectoplasm secretes or colorless, thin, firm, elastic & cutmembrane which covered the body is called pellicle or, periplast which is responsible for a definite & constant shape of the

The surface of pellicle has a great number of polygonal or hexagonal areas bearing the opening of trichocyst.

ach hexagonal areas has a central depression or circum ciliary space from which a cilium comes out. All cilia are equal in size except those of the posterior end which are longer and called caudal tuft. The cilia originate from the basal granules or kinetesomes. [cilia

in length and 0.27 & in diameter, 10,000 – 14,000 in number]

The cytoplasm beneath the pellicle is clearly differentiated into two regions i.e. outer ectoplasm or cortex & inner endoplasm or


The upper dorsal or aboral surface is convey while the ventral or oral

It has greatest diameter just behind the centre of the body. ows a large shallow oblique depression, the

oral groove which posteriorly leads to a deeper conical vestibule which in turn communicates with a buccal cavity having a basal

The ectoplasm secretes or colorless, thin, firm, elastic & cuticular membrane which covered the body is called pellicle or, periplast which is responsible for a definite & constant shape of the

The surface of pellicle has a great number of polygonal or hexagonal

ach hexagonal areas has a central depression or circum ciliary space

All cilia are equal in size except those of the posterior end which are

esomes. [cilia – 10-14,000 in number]

The cytoplasm beneath the pellicle is clearly differentiated inner endoplasm or


Ectoplasm: -

It surrounds the inner mass of the endoplasm forms a clear, dense, thin peripheral layer which is tough, elastic, supporting & protective. It contains basal bodies of cilia or kinetosome, kinetodesmata and trich

Kinetosome: -

The cilium is joint to a solid body below the pellicle is called kinetesome or basal granules or basal body. It is self reproducing unit and progenitors of new cilia. It is either centriole or its derivatives.


It surrounds the inner mass of the endoplasm forms a clear, dense, thin peripheral layer which is tough, elastic, supporting & protective. It contains basal bodies of cilia or kinetosome, kinetodesmata and trich

The cilium is joint to a solid body below the pellicle is called kinetesome or basal granules or basal body. It is self reproducing unit and progenitors of new cilia. It is either centriole or its derivatives.


It surrounds the inner mass of the endoplasm forms a clear, dense, thin peripheral layer which is tough, elastic, supporting & protective. It contains basal bodies of cilia or kinetosome, kinetodesmata and trichocyst.

The cilium is joint to a solid body below the pellicle is called kinetesome or basal granules or basal body. It is self reproducing unit and


Kinetodesmata: -

In paramecium a single ciliary rootlet or fibril called kinetodesmos or km fibrils arises from each kinetosome and runs for some distance tapering anteriorly.

Trichocyst: -

Numerous peculiar, tiny spindle shaped or cigar shaped organelles present beneath the pellicle. Each trichocyst is a minute organelle measuring 4 & by 2 &. It opens to the exterior through a minute pore present on the ridge of hexagonal areas of pellicle


In paramecium a single ciliary rootlet or fibril called kinetodesmos or km fibrils arises from each kinetosome and runs for some distance

Numerous peculiar, tiny spindle shaped or cigar shaped organelles present beneath the pellicle. Each trichocyst is a minute organelle . It opens to the exterior through a minute pore present on the ridge of hexagonal areas of pellicle.


In paramecium a single ciliary rootlet or fibril called kinetodesmos or km fibrils arises from each kinetosome and runs for some distance

Numerous peculiar, tiny spindle shaped or cigar shaped organelles present beneath the pellicle. Each trichocyst is a minute organelle . It opens to the exterior through a minute pore


The trichocysts contain a shaft with a terminal pointed tip called the spike or barb covered by a cap. When the animal is irritated, the protoplasm surrounding the trichocysts suddenly contracts, the caps of trichocysts lifted and water fills in. The swelling substance expands and is discharged as long sticky threads which serve as organs of defense.

Endoplasm: - Below the ectoplasm is a semi fluid granular endoplasm which shows a streaming movement called cyclosis. It contains nucleus, contractile granules of starch, glycogen & fat, mitochondria. Golgi bodies, ribosomes & other cytoplasmic inclusions of varying size, shape & character.


The trichocysts contain a shaft with a terminal pointed tip called the spike or barb covered by a cap. When the animal is irritated, the protoplasm surrounding the trichocysts suddenly contracts, the caps of trichocysts lifted and water fills swelling substance expands and is discharged as long sticky threads which serve as organs of defense.

Below the ectoplasm is a semi fluid granular endoplasm which shows a streaming movement called cyclosis. It contains nucleus, contractile vacuole, food vacuole, reserve food granules of starch, glycogen & fat, mitochondria. Golgi bodies, ribosomes & other cytoplasmic inclusions of varying size, shape & character.

www.nepeducation.com Abhay Mishra The trichocysts contain a shaft with a terminal pointed tip called the When the animal is irritated, the protoplasm surrounding the trichocysts suddenly contracts, the caps of trichocysts lifted and water fills swelling substance expands and is discharged as long sticky

Below the ectoplasm is a semi fluid granular endoplasm which vacuole, food vacuole, reserve food granules of starch, glycogen & fat, mitochondria. Golgi bodies, ribosomes & other cytoplasmic inclusions of varying size, shape & character.


Nuclear apparatus: - The nuclear apparatus of paramecium shows dimorphic natuhas two types of nuclei i.e. heterokaryotic. A. Large macro or mega nucleus:

It is granular and roughly kidney shaped or bean shaped & without a nuclear membrane. It contains many nucleoli.

It controls all the vital activities of the body except reproduction, hence it is called trophic or vegetative nucleus. It is derived from the micronucleus during reproductive processes and always divides amitotically.

B. A smaller micronucleus: It is lodged in a depression on the surface of the meganucleus.

It is usually spherical and with a definite nuclear membrane.It controls the reproductive activities of the organism and

undergoes mitosis or meiosis.

Contractive Vacuole: -

Between the ectoplasm & endoplasm near each end, towards the dorsal surface is a large C.V. The position of C.V. is definite but they are temporary structure. Around each C.V. are 6 canals in the endoplasm.

The vacuoles are excretory, they remove ammonium compound & COtheir primary function is hydrostat


The nuclear apparatus of paramecium shows dimorphic natuhas two types of nuclei i.e. heterokaryotic. Large macro or mega nucleus: -

It is granular and roughly kidney shaped or bean shaped & without a nuclear membrane. It contains many nucleoli.

It controls all the vital activities of the body except eproduction, hence it is called trophic or vegetative nucleus. It is

derived from the micronucleus during reproductive processes and always divides amitotically. A smaller micronucleus: -

It is lodged in a depression on the surface of the meganucleus. is usually spherical and with a definite nuclear membrane.

It controls the reproductive activities of the organism and undergoes mitosis or meiosis.

Between the ectoplasm & endoplasm near each end, towards the arge C.V. The position of C.V. is definite but they are

temporary structure. Around each C.V. are 6 – 10 radiating or feeder

The vacuoles are excretory, they remove ammonium compound & COtheir primary function is hydrostatic or osmoregulatory in function.


The nuclear apparatus of paramecium shows dimorphic nature. It It is granular and roughly kidney shaped or bean shaped &

eproduction, hence it is called trophic or vegetative nucleus. It is derived from the micronucleus during reproductive processes and

It is lodged in a depression on the surface of the meganucleus. is usually spherical and with a definite nuclear membrane.

It controls the reproductive activities of the organism and

Between the ectoplasm & endoplasm near each end, towards the arge C.V. The position of C.V. is definite but they are

10 radiating or feeder

The vacuoles are excretory, they remove ammonium compound & CO2 but ic or osmoregulatory in function.


Food Vacuole: -

Recently termed gastrioles by valvosky. They differ in shape and size according to the nature of the ingested food particles, but mostly they are rounded in forms can be seen moving with nature.


Recently termed gastrioles by valvosky. They differ in shape and size according to the nature of the ingested food particles, but mostly they are rounded in forms can be seen moving with cyclosis. It is non-contractile in


Recently termed gastrioles by valvosky. They differ in shape and size according to the nature of the ingested food particles, but mostly they are

contractile in

external structure of paramecium

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