Similarities and differences between plants and animals. Comparison of features of plant and animal cells

These structures, despite the unity of origin, have significant differences.

General plan of cell structure

Considering cells, it is necessary first of all to recall the basic laws of their development and structure. They have common features structures, and consist of surface structures, cytoplasm and permanent structures - organelles. As a result of vital activity, organic substances, which are called inclusions, are deposited in them in reserve. New cells arise as a result of the division of maternal ones. During this process, two or more young structures can be formed from one initial structure, which are an exact genetic copy of the original ones. Cells that have the same structural features and functions are combined into tissues. It is from these structures that the formation of organs and their systems occurs.

Comparison of plant and animal cells: table

On the table you can easily see all the similarities and differences in the cells of both categories.

Main differences

Comparison of vegetable and animal cell indicates a number of differences in the features of their structure, and hence the processes of life. So, despite the unity of the general plan, their surface apparatus differs in chemical composition. Cellulose, which is part of the cell wall of plants, gives them permanent form. Animal glycocalyx, on the contrary, is a thin elastic layer. However, the most important fundamental difference of these cells and the organisms they form is the way they feed. Plants have green plastids called chloroplasts in their cytoplasm. On their inner surface, a complex chemical reaction converting water and carbon dioxide into monosaccharides. This process is only possible if sunlight and is called photosynthesis. The by-product of the reaction is oxygen.

conclusions

So, we compared the plant and animal cells, their similarities and differences. Common are the plan of the structure, chemical processes and composition, division and genetic code. At the same time, plant and animal cells fundamentally differ in the way they nourish the organisms they form.

According to Theodor Schwann's cellular theory, the cell is the unit of all living things. A comparison of plant and animal cells shows that they are homologous because they have a similar structure. The structures of plants and animals differ in specific organelles, membranes and the number of organelles.

To compare the structure of plant and animal cells, it should be remembered that both species belong to eukaryotes: they have a nucleus and are capable of mitotic division.

similarity

Comparative characteristics of plant and animal cells reveal much in common. In addition to the nucleus, other similar organelles are present in the cytoplasm.

The table contains description and functions.

Eukaryotes always contain a membrane, cytoplasm and nucleus.

Differences

Despite a number of similarities, eukaryotes have several differences.

A general comparison of plant and animal cells is presented in the table.

Comparison of the structure of plant and animal cells concerns their condition. Some plant tissues are formed by dead cells.

Note! In organisms of vertebrates and invertebrates, tissues are always alive. An exception is keratinized epidermal flakes on the surface of human skin.

Plants

The plant structure is distinguished by less plasticity. It does not contain a cell center and an elastic plasmalemma.

Wall

Comparison of plant and animal cells should begin with a strong cell wall, which includes cellulose. Cell plastic forms the primary and secondary membranes.

The first is formed outside immediately after division, the second is formed as it grows between the primary membrane and the cytoplasmic membrane. It contains more cellulose and less water.

The wall contains many pores that form tubules (plasmodesmata) through which eukaryotes exchange substances.

Organelles

Comparing plant and animal cells, specific organelles that are present only in the cytoplasm of plants should be distinguished:

• plastids are membrane organelles that perform different functions;
• - a large membrane organelle that stores a supply of nutrients.

According to the functional purpose, plastids can be of three types:

• chloroplasts - contain chlorophyll and carry out photosynthesis;
• leukoplasts - store starch, fats, proteins;
• chromoplasts - contain colored pigments that give color to the petals.

The vacuole is formed by the ER and the Golgi apparatus. It is assembled from many separated vesicles and occupies most of the structure, pushing the cytoplasm aside. Accumulates, stores, digests substances. In protozoa, vertebrates, and invertebrates, lysosomes are often referred to as vacuoles.

Note! Most leukoplasts are found in roots. In the light they turn into chloroplasts.

Heterotrophs

Membrane

An animal cell is distinguished, first of all, by the absence of a cell wall. The cytoplasm is bounded by an elastic cytoplasmic membrane or plasmalemma.

The membrane consists of lipids that form the outer and inner layers, and proteins that perform transport, receptor, and enzymatic functions. Cholesterol, which is part of the composition, gives rigidity to the plasma membrane.

Organelles

Contains two specific ones:

• cell center,
• lysosome.

Compare the process of division of eukaryotes in plants and animals. In both cases, a “spindle of division” is built, consisting of microtubules that attach to chromosomes. However, in plants, this process is carried out at the expense of the cytoskeleton, and in other tissues through the cell center.

The centrosome or cell center is an animal organoid consisting of two protein structures - centrioles, lying at right angles to each other. One centriole is the parent centriole, the other is the daughter centriole. The mother has protein “blotches” on the surface - satellites that collect microtubules.

Before mitosis, centrioles double and diverge towards the poles. The assembly of the "spindle of division" begins. At the same time, chromosomes line up at the equator, to which microtubules are attached. During disassembly of microtubules, the “spindle of division” pulls parts of the chromosomes to different poles.

The lysosome is a single-membrane organelle that is formed in the cisterns of the Golgi complex and performs a digestive function. Inside the lysosome contains enzymes, merging with fat droplets or solid particles, splits them.

The conclusion that plant eukaryotes do not contain lysosomes is not entirely correct. The function of lysosomes is performed by vacuoles, but can also be seen in plant cytoplasm small vesicles resembling lysosomes.

Chemical composition

If we consider chemical composition, That Comparative characteristics plant and animal structures shows the commonality of their origin. Most of the organic and inorganic substances, which are part of eukaryotes, is the same. These include water, mineral salts, proteins, carbohydrates, nucleic acids, fats. The only difference is that plants contain cellulose.

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Summing up

Common to plant and animal cells is the presence of similar organelles: nucleus, mitochondria, ER, Golgi apparatus, and others. They differ in specific organelles and the structure of the shell. Plants contain plastids and large vacuoles, but there is no centrosome that plays important role in non-plant cell division.

The development of wildlife on earth led to the formation of two main groups of organisms - plants and animals.
Between animals and plants, despite external differences, there is much in common.

The similarity of plant and animal cells is found at the elementary chemical level. Modern methods chemical analysis found about 90 elements in the composition of living organisms periodic system. At the molecular level, the similarity is manifested in the fact that proteins, fats, carbohydrates, nucleic acids, vitamins, etc. are found in all cells.

A feature of the molecular organization of plant cells is that they contain a photosynthetic pigment - chlorophyll. Thanks to photosynthesis, oxygen accumulates in the Earth's atmosphere and hundreds of billions of tons of organic matter are formed annually.

Plants, like animals, have such living properties as growth (cell division due to mitosis - approx. site), development, metabolism, irritability, movement, reproduction, and the sex cells of animals and plants are formed by meiosis and, in contrast to somatic have a haploid (n) set of chromosomes.

The cells of both plants and animals are surrounded by a thin cytoplasmic membrane. However, plants still have a thick cellulose cell wall. Cells surrounded by a hard shell can perceive from environment the substances they need only in a dissolved state. Therefore, plants feed osmotically. The intensity of nutrition depends on the size of the surface of the plant's body in contact with the environment. As a result, most plants show significantly more high degree dismemberment than in animals, due to the branching of shoots and roots.

The existence of solid cell membranes in plants determines another feature of plant organisms - their immobility, while animals have few forms that lead an attached lifestyle. That is why the distribution of animals and plants occurs in different periods ontogeny: animals settle in the larval or adult state; plants develop new habitats by wind or animal transfer of rudiments (spores, seeds) that are at rest.

Plant cells differ from animal cells in special plastid organelles, as well as in a developed network of vacuoles, which largely determine the osmotic properties of cells. Animal cells are isolated from each other, while in plant cells the channels of the endoplasmic reticulum communicate with each other through pores in the cell wall. Glycogen is stored as reserve nutrients in animal cells, while starch is stored in plant cells.
The form of irritability in multicellular animals is a reflex, in plants - tropisms and nastia. In plants, both sexual and asexual reproduction occur, and in the vast majority of them there is an alternation of sexual and asexual generations. In animals, the determining form of reproduction of offspring is sexual reproduction.

Lower unicellular plants and unicellular protozoa are difficult to distinguish not only externally. For example, Euglena green, an organism that seems to be on the border of the plant and animal worlds, has mixed nutrition: in the light it synthesizes organic substances with the help of chloroplasts, and in the dark it feeds heterotrophically, like an animal. Plant growth is almost continuous, and in most animals it is limited to a certain period of ontogeny, after which growth stops. It is undeniable that modern plants and animals had common ancestors. It was they who served as a common root for the evolutionary development and divergence of plants and animals.

Differences in the structure of plant and animal cells

In the process of evolution, due to the unequal conditions for the existence of cells of representatives of various kingdoms of living beings, many differences arose. Compare the structure and vital activity of plant and animal cells.

The main difference between the cells of these two kingdoms lies in the way they are nourished. Plant cells containing chloroplasts are autotrophs, i.e., they themselves synthesize the organic substances necessary for life at the expense of light energy in the process of photosynthesis. Animal cells are heterotrophs, that is, the source of carbon for the synthesis of their own organic substances for them is organic substances that come with food. These same nutrients, such as carbohydrates, serve as a source of energy for animals.

There are exceptions, such as green flagellates, which are capable of photosynthesis in the light, and feed on ready-made organic substances in the dark. To ensure photosynthesis, plant cells contain plastids that carry chlorophyll and other pigments.

Since a plant cell has a cell wall that protects its contents and ensures its constant shape, a partition is formed between daughter cells during division, and an animal cell that does not have such a wall divides with the formation of a constriction.

A sharp boundary between animals and plants cannot be drawn. If the higher, complexly organized animals and plants always differ sharply from each other in many ways, then their lower forms, especially unicellular animals and plants, often have similarities. This indicates a common origin of animals and plants.

Have cellular structure;

Irritability

6. limited growth.

Subkingdom Multicellular

1. Two-layer radially symmetrical (sponges, coelenterates)

2. Three-layer bilaterally symmetrical (worms, mollusks, arthropods)

3. Three-layer radially symmetrical (echinoderm)

Basic aromorphoses:

1. multicellularity

2. the appearance of symmetry (in the lower ones - radial; in the higher ones - two-sided)

3. specialization of cells and their differentiation

4. Appearance of tissues

5. the appearance of nerve cells and the nervous system (not everyone)

6. the appearance of intracavitary digestion (partial or complete)

sponge type(5 thousand species)

The origin is possible from colonial flagellates. They live in the seas, lead an attached lifestyle. There are both solitary and colonial forms. Freshwater sponge - bodyaga.

Basic aromorphoses:

1. Multicellularity.

2. Differentiation of cells into a range of cell types

3. The appearance of germ cells specialized for reproduction.

Structure. The shape of the body resembles a glass or a bag. The whole body is riddled with pores. Through them, water with dissolved oxygen and food particles penetrate into the internal cavity. Water comes out through the outlet hole - the mouth. The outer layer of cells - ectoderm, consists of flat surface cells (pinacocytes). The inner one - endoderm - is built from flagellar cells - choanocytes (they capture food, provide water flow into the body). Amebocytes also take part in nutrition. Digestion is intracellular. Between the ecto- and endoderm there is a mesoglea (gelatinous substance), in which there are various cells: amoebocytes, stellate supporting cells (collencites), skeletal cells (sclerocytes), undifferentiated cells - archeocytes, mature and immature gametes, sometimes there are underdeveloped myocytes. Among pinacocytes, special cells stand out - porocytes, they have a through channel, close and open pores.

reproduction asexual (budding or by the formation of special lumps of cells - gemmules) and sexual. Hermaphrodite or dioecious.

**In the process of ontogenesis, a perversion (inversion) of the germ layers occurs, i.e. outer layer cells in larvae occupies the position of the inner layer in adult sponges and vice versa.

medical significance:

bodyaga in medicinal purposes(bruising treatment)

toilet sponges

· biological purification of natural waters - filterers.

· glass sponges - souvenirs.

Type Intestinal(9 thousand species)

Origin from multicellular flagellates (the first multicellular animals of the phagocytella type).

Classes: 1. Hydroid (able to move, but do it reluctantly)

2. Scyphoid = Jellyfish (mobile)

3. coral polyps= Corals (sessile).

Basic aromorphoses:

1. multicellularity;

2. formation of the first tissues: ectoderm and endoderm;

3. ray symmetry as a form of internal order;

4. differentiation of cells into a number of cell types;

5. the emergence of a nervous system consisting of individual cells interconnected by processes (network or diffuse NS);

6. appearance of partially intracavitary digestion.

general characteristics:

1) Two-layered (ectoderm and endoderm, between them gelatinous mesoglea).

2) Symmetry is ray.

3) The intestinal cavity ends blindly. They have partially abdominal and intracellular digestion.

4) They have stinging cells (protection and hunting).

5) Soft-bodied, but may have an external or internal skeleton.

6) Reproduce sexually and asexually(budding, fragmentation). In some, the alternation of generations, the asexual generation of polyps, is replaced by a sexual generation - jellyfish.

7) Nervous system - diffuse type.

Significance in nature and human life:
1) a link in the food chain, regulate the number of fish, biological treatment sea ​​waters from suspended organic matter.
2) poisonous jellyfish(sea wasp, cross jellyfish)
3) scyphoid jellyfish can exterminate fish, hydra eats fish fry.

4) symbiosis with some animals and plants, for example, sea anemones and hermit crabs, green hydra and chlorella algae.

5) some jellyfish (Aurelia, Rapillema) are eaten by humans
6) coral polyps - a) reef formation; b) deposits of calcareous corals, an important link in the cycle of calcium and carbon dioxide → formation of limestones (CaCO 3) → construction material; c) used for the manufacture of art and jewelry; d) some are poisonous.

Class Hydroids(3 thousand species)

Solitary and colonial forms, predominantly live in the seas.

Freshwater polyp hydra.. External structure: sole, stalk, trunk, tentacles (from 5 to 12); internal structure: mouth, intestinal cavity.

Ectoderm: 1) epithelial-muscular cells
2) glandular (release substances that promote attachment)
3) sensitive
4) stinging
5) nervous (in the mesoglea)
6) intermediate (at the border)
7) sexual (formed from intermediate).

Endoderm: 1) epithelial-muscular cells
2) glandular
3) digestive.

reproduction sexual and asexual (budding). They can be hermaphrodites or dioecious. Hydra lives one summer, hibernates in the form of a zygote.

Movement: steps; on tentacles; on the sole, due to the contraction of muscle fibers.

High ability to regenerate.

Class Scyphoid jellyfish (200 species)

Exclusively marine free-swimming animals. They are 98% water.

Structure. They look like a bell or an umbrella. Tentacles along the edge of the umbrella. On the lower concave side of the oral stalk with mouth opening, usually framed by oral lobes. The intestinal cavity has radial canals that open into an annular canal that lies along the edge of the umbrella.

They have sense organs: "eyes", statocytes (feel the approach of a storm), "olfactory fossa".

reproduction sexual and asexual. Life cycle with alternating sexual and asexual forms. Gametes are produced in the endoderm. Fertilization is often external. A larva emerges from the egg - planula, first swims, then attaches to the substrate, a polyp (scyphistoma) develops from it. Then it buds in transverse constrictions ("a stack of plates or discs"), young jellyfish (ethers) are separated.

Class Coral polyps (6 thousand species)

1) solitary - sea anemones (live from 15 to 66 years);

2) colonial - corals.

There is no medusa stage in the life cycle.

The intestinal cavity is divided by partitions.

They have a skeleton - horny or calcareous.

They reproduce by budding or sexually. Gametes are produced in the endoderm. A planula emerges from the fertilized eggs, which attaches and turns into a polyp. Colonies are formed by budding.

Type flatworms(12 thousand species)

Basic aromorphoses:

1) The emergence of the third germ layer- mesoderm, which gives rise to new organs and organ systems (excretory, muscular).

2) Bilateral symmetry - great activity, the ability to swim and crawl.

3) The appearance of the front end of the body with a complex of sensory organs: sight, smell, touch.

4) The emergence of the nervous system (ladder type) consisting of lateral nerve trunks connected by jumpers; concentration of nerve cells at the anterior end of the body.

5) Education digestive system, including the anterior and middle sections, providing abdominal digestion.

6) Emergence of an excretory system consisting of individual cells - protonephridia.

7) Formation of the reproductive system - permanent gonads.

General characteristics:

1. Flat, elongated, bilaterally symmetrical body.

3. Skin-muscular sac formed by three layers of muscles (in free-living).

4. There is no body cavity, the spaces between the organs are filled with parenchyma.

6. Excretory system - individual cells of the parenchyma and protonephridia - a system of tubules.

8. Nervous system - ladder type

Includes 9 classes, of which we will consider three.

Class Ciliary worms or Turbellaria (3.5 thousand species)

Planaria is white. Size 0.5-1.5 cm. It has a skin-muscular sac (4 types of muscles). Movements: crawls and swims (plans slightly bending the body). Sense organs: eyes (from 2 to several tens) and tentacles. The digestive system has several parts: mouth → pharynx → branches of the intestine X no anus. Hermaphrodite. Reproduction: sexual (with poor conditions) and asexual (with favorable conditions - fragmentation, budding). Development is direct in freshwater, with metamorphosis in marine. They live in water bodies or near them in wet places.

Meaning:

1) predators

3) enter the food chain.

Class Flukes or Trematodes (4 thousand species)

Life cycle of the liver fluke.

Medical Significance:

1) liver fluke causes fascioliasis. May cause blockage of the liver ducts and rupture of blood vessels. The disease is very difficult. Treatment is operative.

3) Blood fluke - lives in the vessels of the abdominal cavity, causes schistosomiasis, common in tropical regions of Asia, Africa and South America. Cause tissue destruction in the kidneys and bladder. Eggs pass into the water with urine. Infection of a person occurs when bathing, when the larvae penetrate the skin and penetrate into the blood, reach large veins and turn into adult worms.

Class Tapeworms or Cestodes (more than 3 thousand species)

Life cycle of a bull tapeworm.

Main host is human, intermediate host is large cattle. Mature segments stuffed with eggs from the feces of a sick person fall on the soil, where cattle can swallow them along with the grass. In the intestines of the animal, microscopic larvae with hooks (oncospheres) emerge from the eggs. Then the larva leaves the shell and penetrates through the intestinal wall into the bloodstream, spreads throughout the body of the animal and penetrates the muscles. Here she transforms into a larva new form- Finnu - a bubble the size of a pea, inside of which there is a tapeworm head with a neck. Infection of a person occurs when eating meat (poorly fried) containing Finns. In the human intestine, under the influence of bile, the head turns out, attaches to the wall, and the growth of the body of the worm begins.

Medical Significance:

1) Cestodes: bovine, pork tapeworm - cause diseases - cestodosis. They cause exhaustion of a person, intoxication, disruption of the intestines. The person may be intermediate host pork tapeworm, and then Finns develop in his muscles. With their presence, the Finns can cause serious illness.

Type Roundworms or Nematodes (20 thousand species)

Descended from free-living flatworms in the Proterozoic.

Basic aromorphoses:

1) The appearance of a body cavity filled with fluid (serves as a hydroskeleton and participates in metabolism).

2) Formation of the peripharyngeal nerve ring.

3) The appearance of the hindgut and the anus (the process of digestion has become continuous).

4) Separation of the muscle layer into longitudinal strands, increasing the efficiency of movement..

5) Dioeciousness (increasing the combinative diversity of offspring).

General characteristics:

1) The body is elongated, non-segmented. Round in diameter.

2) The body is covered with a cuticle.

3) They have a body cavity filled with fluid.

4) The skin-muscular sac is formed by skin and 4 ribbons of longitudinal muscles.

5) The nervous system consists of the peripharyngeal ring and nerve trunks (abdominal and dorsal). Sensory organs are poorly developed, usually these are the organs of touch around the mouth.

6) Digestive system: mouth → muscular pharynx → esophagus → intestine ends with an anus.

7) Excretory system - excretory canals and unicellular skin glands.

8) Dioecious. Reproduction is only sexual.

9) The constancy of the cellular composition of the body and the lack of the ability to regenerate.

Life cycle of human roundworm.

Adult roundworms live in the human small intestine. Eggs covered with a very dense shell (incredible viability) fall into the soil with faeces. After 10 - 15 days, a larva develops inside the egg, now human infection can occur. An egg with a larva inside enters through the mouth into the intestines, where a microscopically small larva emerges, penetrating through the intestinal wall into the blood. The migration of larvae begins with blood flow to the heart, then to the lungs. Here the larvae leave the bloodstream and enter the pulmonary vesicles, then ascend through the bronchioles and bronchi into the trachea, reach (cough) the pharynx and are swallowed again. Now they enter the intestines, where adult worms grow.

Medical Significance:

emit harmful, toxic substances; patients have fever, heart rhythm disturbances and other symptoms of poisoning.

The larvae, getting into the lungs, cause hemoptysis, and also open the way for bacteria to the internal organs.

Ascariasis prevention measures: wash vegetables and fruits, hands before eating and after going to the toilet, fight flies and cockroaches.

Meaning in nature:

1) Free-living - live in the soil (tens of millions of worms are found in 1 m 2 of soil). Benefit, mineralize plant and animal residues. For example, rotifers.

2) A link in the food chain of aquatic and soil communities.

Type Annelids or Annelids (9 thousand species)

Basic aromorphoses:

1. Appearance secondary cavity the body is a coelom having its own walls.

2. Dividing the body into segments.

3. Appearance of the brain ganglion, peripharyngeal nerve ring and ventral nerve cord.

4. The appearance of the circulatory system.

5. Appearance respiratory system(gills)

6. Complication of the digestive system, the appearance of departments, in particular the stomach.

7. Emergence of limbs - parapodia.

8. Formation of a multicellular excretory system.

Insect classification

Two groups

1) Primary wingless - a very primitive group, a typical representative of the sugar silverfish (we do not study at school).

2) Winged. Among them, detachments are distinguished, the development of which occurs with complete (Coleoptera or beetles; Hymenoptera; Diptera; Lepidoptera or butterflies;) and incomplete (cockroaches, orthoptera, lice, bugs) transformation. See table: "Squads of insects"

Insect ancestors

Ancient arthropods similar in appearance to modern centipedes.

The value of insects in nature and human life:

Type Echinoderms (6 thousand species)

Echinoderms are an independent and very peculiar type of animal. According to the plan of the structure, they are incomparable with any other animals, and due to the peculiarities of organization and the original shape of the body resembling a star, cucumber, flower or ball, they have long attracted attention. The name "echinoderms" was given by the ancient Greeks.

Ancestors

Echinoderms and chordates have the same ancestors. This is a group of ancient polychaete rings.

Classification of echinoderms

five classes

Similarities and differences between animals and plants.

Similarities of plants and animals:

Consist of complex organic substances: proteins, fats and carbohydrates;

Have a cellular structure;

They have a similar nature of life processes (metabolism and energy);

Growth by cell division and similar methods of reproduction;

Encoding, transmission and implementation hereditary information;

Irritability

This indicates the relationship of plants and animals, their origin from a common ancestor (divergent path of development of the organic world).

Differences between plants and animals.

General characteristics of animals:

1. nutrition with ready-made organic substances (heterotrophic);

2. the absence of a dense outer shell in the structure of cells;

3. in most cases, mobility and the availability of devices for movement

4. actively respond to environmental changes

5. most have various systems bodies

6. limited growth.

A cell is a structural and functional unit of a living organism that carries genetic information, provides metabolic processes, is capable of regeneration and self-reproduction.

There are unicellular individuals and developed multicellular animals and plants. Their vital activity is provided by the work of organs that are built from different tissues. The tissue, in turn, is represented by a collection of cells similar in structure and function.

Cells different organisms have their own characteristic properties and structure, but there are common components inherent in all cells: both plant and animal.

Organelles common to all cell types

Core- one of the important components of the cell, contains genetic information and ensures its transmission to descendants. Surrounded by a double membrane that isolates it from the cytoplasm.

Cytoplasm- a viscous transparent medium that fills the cell. All organelles are located in the cytoplasm. The cytoplasm consists of a system of microtubules, which provides a clear movement of all organelles. It also controls the transport of synthesized substances.

cell membrane- a membrane that separates the cell from external environment, provides the transport of substances into the cell and the excretion of synthesis products or vital activity.

Endoplasmic reticulum- a membrane organelle, consists of tanks and tubules, on the surface of which the synthesis of ribosomes occurs (granular ER). Places where there are no ribosomes form a smooth endoplasmic reticulum. The granular and agranular network are not delimited, but pass into each other and connect with the shell of the nucleus.

Golgi complex- a stack of tanks, flattened in the center and expanded on the periphery. Designed to complete the synthesis of proteins and their further transport from the cell, together with EPS forms lysosomes.

Mitochondria- two-membrane organelles, the inner membrane forms protrusions into the cell - cristae. Responsible for the synthesis of ATP, energy metabolism. Performs a respiratory function (absorbing oxygen and releasing CO 2).

Ribosomes- are responsible for protein synthesis, in their structure there are small and large subunits.

Lysosomes- carry out intracellular digestion, due to the content of hydrolytic enzymes. Break down trapped foreign substances.

Both plant and animal cells have, in addition to organelles, non-permanent structures - inclusions. They appear with an increase in metabolic processes in the cell. They perform a nutritional function and contain:

• Grains of starch in plants, and glycogen in animals;
• proteins;
• lipids are high-energy compounds that are more valuable than carbohydrates and proteins.

There are inclusions that do not play a role in energy metabolism, they contain the waste products of the cell. In the glandular cells of animals, inclusions accumulate a secret.

Organelles found only in plant cells

Animal cells, unlike plant cells, do not contain vacuoles, plastids, or cell walls.

cell wall formed from the cell plate, forming the primary and secondary cell membranes.

The primary cell wall occurs in undifferentiated cells. During maturation, a secondary membrane is laid between the membrane and the primary cell wall. In its structure, it is similar to the primary, only it has more cellulose and less water.

The secondary cell wall is equipped with many pores. A pore is a place where there is no secondary wall between the primary membrane and the membrane. The pores are arranged in pairs in adjacent cells. Placed nearby cells communicate with each other by plasmodesma - this is a channel, which is a strand of cytoplasm lined with a plasmolemma. Through it, cells exchange synthesized products.

Functions of the cell wall:

1. Maintenance of cell turgor.
2. Gives shape to cells, acting as a skeleton.
3. Accumulates nutritious foods.
4. Protects from external influences.

Vacuoles- organelles filled with cell sap are involved in the digestion of organic substances (similar to the lysosomes of an animal cell). Formed with the help joint work EPS and the Golgi complex. At first, several vacuoles form and function; during cell aging, they merge into one central vacuole.

plastids- autonomous two-membrane organelles, the inner shell has outgrowths - lamellae. All plastids are divided into three types:

• Leucoplasts- non-pigmented formations, capable of storing starch, proteins, lipids;
• chloroplasts- green plastids, contain the pigment chlorophyll, are capable of photosynthesis;
• chromoplasts– crystals orange color due to the presence of the pigment carotene.

Organelles found only in animal cells

difference plant cell from the animal is the absence of a centriole, a three-layer membrane in it.

Centrioles- paired organelles located near the nucleus. They take part in the formation of the spindle of division and contribute to the uniform divergence of chromosomes to different poles of the cell.

plasma membrane- Animal cells are characterized by a three-layer, durable membrane, built from lipids and proteins.

Comparative characteristics of plant and animal cells

Plant cells, thanks to chloroplasts, carry out photosynthesis processes - they convert the energy of the sun into organic substances, animal cells are not capable of this.

Mitotic division of a plant occurs mainly in the meristem, characterized by the presence of an additional stage - preprophase; in the animal body, mitosis is inherent in all cells.

The size of individual plant cells (about 50 µm) exceeds the size of animal cells (about 20 µm).

The relationship between plant cells is carried out due to plasmodesma, animals - with the help of desmosomes.

Vacuoles of a plant cell occupy most of its volume, in animals they are small formations in small quantities.

The cell wall of plants is made up of cellulose and pectin; in animals, the membrane is made up of phospholipids.

Plants are not able to move actively, therefore they have adapted to the autotrophic way of nutrition, synthesizing independently all the necessary nutrients from inorganic compounds.

Animals are heterotrophs and use exogenous organic matter.

The similarity in the structure and functionality of plant and animal cells indicates the unity of their origin and belonging to eukaryotes. Their distinctive features conditioned in a different way life and nutrition.