How do protozoa feed and excrete?

Amoeba feed mainly on monatophytes and small protozoa. When the amoeba touches the food, it stretches out the pseudopods to surround it (phagocytosis), and with the food, it also brings some water to form a food vacuole, which separates from the plasma membrane and enters the endoplasm and flows with the endoplasm. The food vacuole and lysosome are fused, and the food is digested by various hydrolytic enzymes contained in the lysosome, and the whole digestion process takes place inside the food vacuole.

The digested food enters the surrounding cytoplasm, and the indigestible material, as the amoeba advances, is used relatively for the back end, and finally excreted through the plasma membrane, a phenomenon called ejection.

In addition to swallowing solid objects, amoebas can also ingest some liquid substances, which is very similar to drinking water, so it is called pinocytosis. That is, some molecules (generally macromolecular compounds) or ions that are small in the liquid environment are adsorbed to the surface of the plasma membrane, so that the membrane reacts, and the depression forms a pipe, and then breaks down at the inner end of the pipe to form some vacuoles, which move to the cytoplasm and combine with lysosomes to form multivesicular bodies (there can be several pinocytosis in a membrane), and the nutrients enter the cytoplasm after digestion. Pinocytosis must be induced by certain substances in order for it to occur.

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Paramecium belongs to single-celled organisms, cells are the most basic living system, and the various components of the cell cooperate into a whole, so that life activities can be self-regulated and highly orderly in a changing environment Cells are not only the basic unit of biological structure, but also the basic unit of biological metabolism and heredity Therefore, a complete cell structure is the basis of various life activities

Therefore, c

Protozoa feed for nutrients and excretion, such as paramecium and amoeba, are all done in a single cell.

The process of protozoan eating water and excreting waste is a simple osmosis, through which protozoa can inhale and excrete dissolvable objects through the body wall. In addition, many protozoa have organelles that hunt and eat. Some protozoa also have very delicate esophagus.

Some protozoa will use their pseudopods to surround their food, or use their cilia to create a stream of water to bring food closer. In the body, digestion takes place inside organelles called food vacuoles. Organelles called telescopic bubbles are powerful in removing excess water from the cells.

Choose C. Cilia, nucleus, and contractile vesicles are all organelles. The functional division of paramecium cells is as follows:

Oral groove: feeding.

Outer membrane: respiration (absorption of oxygen in water, excretion of carbon dioxide) macronucleus: nutrient metabolism.

Small nucleus: reproduction.

Food vacuoles: Food vacuoles are produced by paramecium endocytosis and will fuse with primary lysosomes to form secondary lysosomes upon entering the cell.

Expansion bubble and collection tube: collects metabolic waste and excess water, and excretes the extracorporeal anus: excretes food debris.

Cilia: Movement.

c.If you only have A, B, or D, you will not be able to do all of the above activities alone.

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Protozoa is a single cell, and its only cells have all the functions needed for survival, such as feeding, digestion, defense, etc., while multicellular organisms have their own cells have their own division of labor, such as epithelial cells mainly manage to resist the external environment, nerve cells make action commands, and so on. No single cell can survive alone, it is a collective. This, of course, results in one cell of protozoa being stronger than one cell of multicellular organisms.

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Because this is the only cell that needs to complete the functions of food intake from the outside world and digestion, excretion, and movement of food. The external environment is unstable, and more must be done to be able to adapt to the environment and survive.

In multicellular animals, the life activities of the whole animal body are completed by many cells in the body, and each cell often performs only a few functions. And each cell is in a relatively stable internal environment, so it does not need to have a more complex structure.

Paramecium, hydra, jellyfish and other coelenterates, earthworms, roundworms, pinworms, snails. Mussels, snails, octopus, abalone, oysters. Starfish, sea cucumbers, sea urchins, shrimp, locusts, spiders, centipedes.

The body is divided into three parts: head, thorax and abdomen, with an exoskeleton, 3 pairs of legs, 2 pairs of wings, body unicellular, paramecium.

Body radiation symmetry, jellyfish.

Schistosomiasis, planarians.

Earthworm roundworm, round worm.

Squid, clams. Starfish bees, butterflies.

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Insects: have an exoskeleton, the body is divided into three parts: head, thorax and abdomen, with 3 pairs of feet, 2 pairs of wings and 1 pair of antennae.

Protozoa : main characteristics: a single-celled animal, the whole body is a cell, the simplest animal in the world, and the lowest animal.

Examples: paramecium, amoeba.

Coelenterates: feed and excrete through the same opening, and the body is radially symmetrical.

Examples: jellyfish, sea stingers.

Flatteneds: feed and excrete through the same opening, dorsal and ventral flattening.

Examples: planarians, schistosomes.

Nematoids: The body is elongated, flattened, and not segmented.

Examples: worms, roundworms.

Annelids: The body is round or flattened, with many body segments.

Examples: earthworms, leeches.

Mollusks: soft bodies, mostly with shells.

Examples: clams, abalone.

Arthropods: the body is segmented, the antennae and feet are segmented, there is an exoskeleton, and there is a phenomenon of "molting" during growth.

Examples: shrimp, ants.

Echinoderms: have no shells on their bodies, have acanthoderm protrusions on their bodies, and live in water.

Examples: starfish, sea cucumbers.