The simplest are unicellular animals, and morphologically their body corresponds to one cell multicellular organism. Physiologically, each individual of the protozoa is an independent organism, in contrast to the cell, which is part of a multicellular organism.
Each protozoan animal has all the basic life functions characteristic of the whole organism: metabolism with assimilation and dissimilation, irritability, movement, reproduction, adaptation to the environment, etc. sense similar to the organs of multicellular animals. But since these devices do not have cellular structure and do not consist of tissues, they are not called organs, but organelles, or organelles.
The organelles of movement are either pseudopodia (pseudopodia), which are temporary projections of protoplasm that arise as needed in various parts of the body, or permanent formations in the form of long and few bundles or short numerous cilia. In some forms, contractile cords (myonemas) are located under the shell, in a number of protozoa there is a complex system of skeletal formations.
In some protozoa, the cellular mouth, differently arranged pharynx, and digestive vacuoles serve as food organelles. Many forms have contractile (pulsating) vacuoles that serve to excrete and regulate osmotic pressure within the body.
The organization of protozoa can, due to the presence of certain organelles, reach considerable complexity (especially in some ciliates).
Sporozoans: coccidia, malarial plasmodium.
Ciliates: balantidia.
Sarcodidae: amoeba dysentery.
Protozoa- the oldest group of living organisms. When the first protozoa arose is not known. In Western literature, protozoa are not considered as animals and are assigned to the kingdom of protists. And according to latest systems among the simplest, several kingdoms are distinguished.
Option II
o A) eyelashes
o B) rhizopodia
o B) undulating membrane
o D) peliculla
o B) isolation of gametes
o B) osmoregulation
o D) carrying water into the cell
o B) opalines have cytostomes
o A) sarcode
o B) unicellular flagellates
o B) colonial flagellates
o D) apicomplexes
o A) palintomy
o B) conjugation
o A) saprophytic
o B) autotrophically
o B) do not eat
o D) by means of a cytostomy
What spore-forming protozoans are characterized by a regular alternation in the life cycle of sporogony, schizogony and homogony?
o A) microsporidia
o B) apicomplexes
o B) ascetosporidia
o D) myxozoans
Which protozoan alternates sporogony and homogony in its life cycle?
o A) ascetosporidia
o B) coccidia
o B) malarial plasmodium
o D) gregarines
What eukaryotes first developed sexual reproduction?
o A) myxosporidium
o B) flagellate
o B) ciliates
o D) sarcode
What cells are not located in the mesoglea of sponges?
o A) pinacocytes
o B) sclerocytes
o B) gonocytes
o D) collencites
17. In sponges, cells that resemble the structure and functions of collared flagellates are called ………………………….. .
18. In sponges related to morphological type leukone, choanocytes are located in:
o A) paragastric cavity
o B) mesoglee
o B) pocket-like invaginations
o D) flagellar chambers
19. A sponge larva, in which macromeres are located inside the blastula, and micromeres with cilia are outside, is called ………………………….
20. Inversion of germ layers in sponges is called:
o A) the emergence of their ectoderm and endoderm
o B) mutual topographic change of ectoderm and endoderm
o C) differentiation of ectoderm and endoderm cells
o D) the occurrence of mesoglea
What stage of development in the life cycle of hydroids prevails over the time of existence?
o B) medusoid
o B) planula
o D) polypoid
22. The life cycle of development with alternation of asexual and sexual forms of reproduction is called …………………….. .
23. Regeneration of body composition in coelenterates occurs due to ...
o A) archeocytes
o B) epithelial-muscular
o B) gonocytes
o D) interstitial
What is ropaliy?
o A) an organ serving to protect
o B) an organ with localization of the sense organs
o B) excretory organ
o D) reproductive organ
25. Choose the correct statement:
o A) in hydroid polyps, the pharynx is ectodermal flattened
o B) in coral polyps, the digestive tract consists only of a multi-chambered endodermal stomach
o B) Scyphoid jellyfish have an ectodermal pharynx
o D) coral polyps have a flattened ectodermal pharynx
What is parthenogenesis?
o A) sexual reproduction with the participation of male and female gametes formed in separate organisms
o B) sexual reproduction involving only female gametes
o C) sexual reproduction with the participation of male and female gametes formed in the same organism
o D) reproduction using somatic cells
35. A single-layer epithelium that secretes the cuticle is called ……………………….
36. The common origin of nemerteans and turbellarians is based on the presence in both of them:
o A) proboscis
o B) circulatory system
o B) parenchyma
o D) through intestine
37. Choose the correct statement: metanephridia are characterized by the following features ...
o A) mesodermal origin, funnel with ciliated epithelium, pores are arranged in pairs and in segments
o B) ectodermal origin, funnel with ciliated epithelium, pores - in pairs and in segments
o B) mixed origin, solenocytes, pores - at the posterior end of the body
o D) mixed origin, funnel with ciliated epithelium, pores - at the posterior end of the body
Option II
1. Choose the correct statement: the following is typical for a unicellular animal ...
o A) no shell, stores glycogen, autotroph
o B) stores starch, heterotroph, no shell
o B) heterotroph, stores glycogen, no shell
o D) stores starch, cellulose shell, autotroph
2. Movement organelles in protozoans are not ...
o A) eyelashes
o B) rhizopodia
o B) undulating membrane
o D) peliculla
3. Choose the correct statement: cilia and flagella are similar, because ...
o A) located in one place
o B) organized according to the formula "9 + 2"
o B) their number is approximately the same
o D) perform specific functions
What is the function of the excretory organelles of protozoa?
o A) excretion of solid metabolites
o B) isolation of gametes
o B) osmoregulation
o D) carrying water into the cell
5. Autotrophic and heterotrophic nutrition among modern eukaryotes is typical for …………………………. .
6. Choose the correct statement: nuclear dualism is ...
o A) polyenergy, in which the nuclei differ morphologically and functionally
o B) polyenergy, in which the nuclei have a similar structure and perform similar functions
o B) monoenergy, in which the core performs one function
o D) monoenergy, in which the nucleus performs several functions
7. Opaline and ciliates differ from each other in the following feature:
o A) opalines are characterized by nuclear dualism
o B) opalines have cytostomes
o C) ciliates are characterized by nuclear dualism
o D) ciliates are covered with many cilia
8. Radiolarians differ from sunflowers in that ...
o A) the former have a central capsule
o B) in the latter, the extracapsular cytoplasm is significantly differentiated
o B) the latter do not have axopodia
o D) the former do not form colonies
9. Phylogenetically older are ...
o A) sarcode
o B) unicellular flagellates
o B) colonial flagellates
o D) apicomplexes
10. The process of formation of microgametes through repeated mitotic division, and macrogametes through its growth, is called ……………………….
11. Asexual reproduction of ciliates occurs through:
o A) palintomy
o B) longitudinal binary fission
o B) conjugation
o D) transverse binary fission
12. Nutrition of ciliates is carried out ...
o A) saprophytic
o B) autotrophically
o B) do not eat
o D) by means of a cytostomy
Body covers.
Body shape, symmetry.
The shape of the body of protozoa and its coloration are extremely diverse and are determined by the specific conditions of existence. Functionally, the anterior end of the flagellate is where the flagellum is attached.
From the influence of the external environment, all protozoa, regardless of the type of their organization, are protected by cell membranes of the most diverse structure. The main structural unit of all types of integument in protozoa is the cytoplasmic membrane. On the inner side of the plasmalemma, submembrane microfilaments or microtubules are usually located.
The appearance of flagella as a locomotor apparatus led to the appearance of relatively one more type of integument in flagellates - dense pellicles. The pellicle is formed due to the compaction of the peripheral layer of the cytoplasm and the presence of supporting fibrils in it. It is reinforced with outgrowths of the radicular system.
The next stage in the complication of the integument is the external skeleton, formed by protein, cellulose and even chitin plates, calcareous, silica structures, as well as glycoprotein gelatinous secretions in some flagellates.
In some protozoa, different types of integument are complicated by the appearance of more or less complex sculpture, that is, a system of more or less regularly located depressions and protrusions that form something like stiffeners (Opalinidomorpha), “reinforced” with microtubules. Such covers are called folded or comb tubulemma.
Infusoria are characterized cortex. The composition of the cortex includes: the pellicle (formed by the membrane and the alveolar system), under the pellicle there is a protein layer - the epiplasm and the kinetosomes complex.
TO general cellular structures include: cytoplasm, nucleus, mitochondria, endoplasmic reticulum, ribosomes, lysosomes, Golgi apparatus, centriole.
One core or several. Depending on the number of nuclei, protozoa are divided into monoenergetic and polyenergetic. Ciliates are characterized by nuclear dualism: the functions of the nuclei (micronucleus and macronucleus) differ.
Special organelles cells are: contractile and digestive vacuoles, microfilaments (participate in the processes of contraction and cell division, form fibrils), microtubules (the main function is the formation of the cytoskeleton, take part in cell division, in the formation of the oral apparatus, hold organelles in a certain position), extrusomas ( diverse in shape, in response to irritation, the contents are thrown out), powder, stigma, flagella and cilia.
inclusions are: fat droplets, protein crystals, symbiotic organisms.
Organelle is tiny cell structure, which performs certain functions inside . The organelles are embedded in the cytoplasm. In more complex eukaryotic cells, organelles are often surrounded by their own membrane. Like the internal organs of the body, organelles are specialized and perform specific functions necessary for the normal functioning of cells. They have a wide range of responsibilities, from generating energy to controlling cell growth and reproduction.
eukaryotic organelles
Eukaryotic cells are cells with a nucleus. The nucleus is an important organelle surrounded by a double membrane called the nuclear envelope that separates the contents of the nucleus from the rest of the cell. Eukaryotic cells also contain various cell organelles. Examples of eukaryotic organisms are animals, plants, and. and contain many of the same or different organelles. There are also some organelles found in plant cells that are not found in animal cells and vice versa. Examples of major organelles found in plant and animal cells include:
- - a structure associated with the membrane, which contains hereditary (DNA) information, and also controls the growth and reproduction of the cell. It is usually the most important organelle in the cell.
- , as energy producers, convert energy into forms that the cell can use. They are also involved in other processes such as division, growth, and.
- - an extensive network of tubules and pockets that synthesizes membranes, secretory proteins, carbohydrates, lipids and hormones.
- - a structure that is responsible for the production, storage and delivery of certain cellular substances, especially from the endoplasmic reticulum.
- - organelles consisting of RNA and proteins and are responsible for protein synthesis. Ribosomes are located in the cytosol or associated with the endoplasmic reticulum.
- - these membrane sacs of enzymes process the organic material of the cell by digesting cellular macromolecules such as nucleic acids, polysaccharides, fats and proteins.
- , like lysosomes are connected by a membrane and contain enzymes. They help detoxify alcohol, form bile acids, and break down fats.
- are fluid-filled, closed structures most commonly found in plant cells and fungi. They are responsible for a wide range of important functions, including nutrient storage, detoxification, and waste elimination.
- - plastids contained in plant cells, but absent in animal cells. Chloroplasts absorb the energy of sunlight for.
- - a rigid outer wall located near the plasma membrane in most plant cells, providing support and protection to the cell.
- - cylindrical structures are found in animal cells and help organize the assembly of microtubules during.
- - hair-like formations on the outside of some cells that carry out cellular locomotion. They are made up of specialized groups of microtubules called basal bodies.
prokaryotic cells
Prokaryotic cells have a structure that is less complex than that of eukaryotic cells. They do not have a nucleus where the DNA is bound by a membrane. Prokaryotic DNA is found in a region of the cytoplasm called the nucleoid. Like eukaryotic cells, prokaryotic cells have plasma membrane, cell wall and cytoplasm. Unlike eukaryotes, prokaryotes do not contain membrane-bound organelles. However, they have some non-membranous organelles such as ribosomes, flagella, and plasmids (circular structures of DNA that are not involved in reproduction). Examples of prokaryotic cells are and.
An organelle is a permanent formation in a cell that performs certain functions. They are also called organelles. An organelle is what allows a cell to live. Just as animals and humans are made up of organs, so every cell is made up of organelles. They are diverse and perform all the functions that ensure the life of the cell: this is the metabolism, and their storage, and division.
What are the organelles?
An organelle is a complex structure. Some of them may even have their own DNA and RNA. All cells contain mitochondria, ribosomes, lysosomes, a cell center, the Golgi apparatus (complex), and the endoplasmic reticulum (reticulum). Plants also have specific cell organelles: vacuoles and plastids. Some also refer to microtubules and microfilaments as organelles.
An organelle is a ribosome, a vacuole, a cell center, and many others. Let's take a closer look at the structure and functions of organelles.
Mitochondria
These organelles provide the cell with energy - they are responsible for They are found in plants, animals, and fungi. These cell organelles have two membranes: outer and inner, between which there is an intermembrane space. What is inside the shells is called the matrix. It contains a variety of enzymes - substances necessary for accelerating chemical reactions. The inner membrane has folds - cristae. It is on them that the process of cellular respiration takes place. In addition, the mitochondrial matrix contains mitochondrial DNA(mDNA) and mRNA, as well as ribosomes, almost similar to those possessed by
Ribosome
This organelle is responsible for the process of translation, in which protein is synthesized from individual amino acids. The structure of the ribosome organelle is simpler than mitochondria - it does not have membranes. This organoid consists of two parts (subunits) - small and large. When the ribosome is idle, they are separated, and when it begins to synthesize protein, they unite. Several ribosomes can also come together if the polypeptide chain synthesized by them is very long. This structure is called a "polyribosome".
Lysosomes
The functions of organelles of this type are reduced to the implementation of cellular digestion. Lysosomes have one membrane, inside of which there are enzymes - catalysts for chemical reactions. Sometimes these organelles not only break down but also digest whole organelles. This can happen during a long starvation of the cell and allows it to live for some more time. Although if the nutrients still do not begin to flow, the cell dies.
and features
This organelle consists of two parts - centrioles. These are formations in the form of cylinders, consisting of microtubules. The cell center is a very important organelle. It is involved in the process of formation of the fission spindle. In addition, it is the center of microtubule organization.
golgi apparatus
It is a complex of disk-shaped membranous sacs called cisterns. The functions of this organoid are sorting, storing and converting certain substances. Here, mainly carbohydrates are synthesized, which are part of the glycocalyx.
The structure and functions of the endoplasmic reticulum
It is a network of tubules and pockets surrounded by a single membrane. There are two types of endoplasmic reticulum: smooth and rough. Ribosomes are located on the surface of the latter. Smooth and rough reticulum perform different functions. The first is responsible for the synthesis of hormones, storage and conversion of carbohydrates. In addition, the rudiments of vacuoles are formed in it - organelles characteristic of plant cells. The rough endoplasmic reticulum contains ribosomes on its surface that produce a polypeptide chain from amino acids. Then it enters the endoplasmic reticulum, and here a certain secondary, tertiary and quaternary structure of the protein is formed (the chain twists in the right way).
Vacuoles
These are organelles. They have one membrane. They accumulate cell sap. The vacuole is essential for maintaining turgor. It also participates in the process of osmosis. In addition, there are They are found mainly in unicellular organisms living in water bodies, and serve as pumps that pump out excess fluid from the cell.
Plastids: varieties, structure and functions
These are also organelles. They are of three types: leukoplasts, chromoplasts and chloroplasts. The former serve to store spare nutrients, mainly starch. Chromoplasts contain various pigments. Thanks to them, the petals of plants are multi-colored. This is necessary for the body in the first place in order to attract pollinating insects.
Chloroplasts are the most important plastids. Most of them are found in the leaves and stems of plants. They are responsible for photosynthesis - a chain of chemical reactions in which the body receives organic substances from inorganic substances. These organelles have two membranes. The chloroplast matrix is called the stroma. It contains plastid DNA, RNA, enzymes, and starch inclusions. Chloroplasts contain thylakoids - membrane formations in the form of a coin. Inside them, photosynthesis takes place. It also contains chlorophyll, which serves as a catalyst for chemical reactions. The thylakoids of chloroplasts are combined into piles - grana. Also in the organelles are lamellae, which connect individual thylakoids and provide a connection between them.
Movement organelles
They are mainly characteristic of unicellular organisms. These include flagella and cilia. The first are present in euglena, trypanosomes, chlamydomonas. Flagella are also present in animal spermatozoa. Cilia are found in ciliates and other unicellular organisms.
microtubules
They provide the transport of substances, as well as the permanent shape of the cell. Some scientists do not classify microtubules as organelles.