What kind of creature is paramecium? What is its structure and function?

Friends who have studied biology believe that paramecium is no stranger to paramecium, although there is only one cell, but its growth ability is also very strong. Let's take a look at what paramecium is. What is its structure and function piece?

What kind of creature is paramecium?

Paramecium is a small, cylindrical protozoan that consists of only one cell and is a single-celled animal. The most common is paramecium. The body length is only 80,300 microns. It is called paramecium because its body shape looks like the sole of an inverted straw sandal from a flat angle.

Paramecium are single-celled animals because they are composed of (one cell), have no chloroplasts in the body, and cannot synthesize organic matter on their own. Food enters their bodies, forms (food vesicles), and is digested in them. Oxygen can be obtained directly from (water) through (surface membrane), and excess water in the two bodies is excreted from (anus).

What is the structure, function and picture of paramecium?

The whole body of paramecium is covered with a thin and elastic surface membrane, which is equivalent to the general cell membrane. The surface of the surface membrane forms many regular hexagonal or quadrilateral cells, each of which has 1 or 2 cilia. Under the electron microscope, it can be seen that the surface film is composed of three layers. The outermost membrane is continuous on the surface of the body and above the cilia. Between the two inner membranes, surface vesicles are formed near the base of each cilia. The surface membrane keeps the paramecium's body in a certain shape. Surface vesicles can not only increase the hardness of the surface membrane, but also do not affect the local bending of paramecium ice, may also be a buffer zone to protect the cytoplasm, and can prevent the internal material from passing through the outer cell membrane.

There are many small and slender filament vesicles under the surface membrane, buried in the ectoplasm and arranged perpendicular to the body surface. The hardness of the barbed vesicle is in a semi-liquid state and can be pressed out of the body through a small hole in the surface membrane under certain conditions. When paramecium is attacked or affected by a weak acid solution, the liquid in the thorn bubble ejects, and when it comes into contact with water, it becomes a slender, sticky silk that can entangle the enemy.

Paramecium is a common fast-moving protozoan. It has an oval shape, like an inverted straw sandal. The paramecium has a purer front end, a sharp back end, and a wider middle and rear part. The surface of the body is covered with a short layer of cilia. Paramecium swims in the water by swinging its cilia, usually swimming forward at the rounded end, so this end is called the front end, but it can also go backwards from time to time. There is a groove from the front of the body, oblique to the middle of the body, called the mouth groove. The side of the mouth groove is the mouth or ventral side of the grass worms. The mouth groove floor is the cell mouth, the cell mouth receives the cell pharynx. The long and strong cilia in the oral groove and the cilia in the pharynx form a fluctuating membrane. when the cilia swings, they can roll bacteria and other small organisms into the body and form food bubbles at the end of the pharynx. An acid is secreted in the cytoplasm around the food bubble, dissolves or digests the food, and is then carried away by the slow circulation of the cytoplasm. Digested food is absorbed by the cytoplasm to form a new cytoplasm; indelible things are excreted from the posterior ventral anus. Paramecium has a definite effect on wastewater purification, because one paramecium can form 60 food bubbles per hour.

Each food bubble can hold 30 bacteria, so each paramecium can swallow 43200 bacteria a day. Although the mouth and anus are fixed structures, they can only be seen when the worm swallows or removes solids.

The cytoplasm of paramecium is also composed of sparse granular endoplasm and transparent and sticky ectoplasm. There is an oval large nucleus near the middle of the endoplasmic body and one or more small nuclei located in the concave part of the greater nucleus. In the paramecium, there is a telescopic bubble in front and back, which contracts alternately and regularly. The position of the telescopic bubble is fixed. At each contraction, the water containing soluble waste is discharged from the body through a small hole in the surface membrane. At this time, the telescopic bubble is invisible. Radiating collection tubes are emitted from the cytoplasm around the telescopic vesicles to collect water and waste. When the telescopic bubble shrinks, the collection tube becomes obvious because it is gradually filled with water and waste; when the collection tube shrinks, the water and waste are sent to the telescopic bubble. Therefore, the expansion and contraction of the two are carried out alternately.

The reproduction of paramecium can be divided into two types: transverse dichotomy and conjugate reproduction. The former is asexual reproduction and the latter is sexual reproduction. The transverse division is that the paramecium elongates in the direction of the transverse axis, the nucleus divides first, and the paramecium hangs in two, about two hours before and after.