Table on biology structure and function of the cell. Apparatus, lysosomes and mitochondria

The elementary and functional unit of all life on our planet is the cell. In this article, you will learn in detail about its structure, the functions of organelles, and also find the answer to the question: “What is the difference between the structure of plant and animal cells?”.

Cell structure

The science that studies the structure of the cell and its functions is called cytology. Despite their small size, these parts of the body have a complex structure. Inside is a semi-liquid substance called the cytoplasm. All vital processes take place here and the constituent parts are located - organelles. Learn more about their features below.

Core

The most important part is the core. It is separated from the cytoplasm by a membrane, which consists of two membranes. They have pores so that substances can get from the nucleus to the cytoplasm and vice versa. Inside is the nuclear juice (karyoplasm), which contains the nucleolus and chromatin.

Rice. 1. The structure of the nucleus.

It is the nucleus that controls the life of the cell and stores genetic information.

The functions of the internal contents of the nucleus are the synthesis of protein and RNA. They form special organelles - ribosomes.

Ribosomes

They are located around the endoplasmic reticulum, while making its surface rough. Sometimes ribosomes are freely located in the cytoplasm. Their functions include protein synthesis.

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Endoplasmic reticulum

EPS can have a rough or smooth surface. The rough surface is formed due to the presence of ribosomes on it.

The functions of EPS include protein synthesis and internal transport of substances. Part of the formed proteins, carbohydrates and fats through the channels of the endoplasmic reticulum enters special storage containers. These cavities are called the Golgi apparatus, they are presented in the form of stacks of "tanks", which are separated from the cytoplasm by a membrane.

golgi apparatus

Most often located near the nucleus. Its functions include protein conversion and the formation of lysosomes. This complex stores substances that were synthesized by the cell itself for the needs of the whole organism, and will later be removed from it.

Lysosomes are presented in the form of digestive enzymes, which are enclosed by a membrane in vesicles and carried through the cytoplasm.

Mitochondria

These organelles are covered with a double membrane:

• smooth - outer shell;
• cristae - the inner layer having folds and protrusions.

Rice. 2. The structure of mitochondria.

The functions of mitochondria are respiration and the conversion of nutrients into energy. The cristae contain an enzyme that synthesizes ATP molecules from nutrients. This substance is a universal source of energy for various processes.

The cell wall separates and protects the internal contents from the external environment. It maintains its shape, provides interconnection with other cells, and ensures the process of metabolism. The membrane consists of a double layer of lipids, between which are proteins.

Comparative characteristics

Plant and animal cells differ from each other in their structure, size and shape. Namely:

• the cell wall of a plant organism has a dense structure due to the presence of cellulose;
• a plant cell has plastids and vacuoles;
• the animal cell has centrioles, which are important in the process of division;
• The outer membrane of an animal organism is flexible and can take on various forms.

Rice. 3. Scheme of the structure of plant and animal cells.

The following table will help to summarize the knowledge about the main parts of the cellular organism:

Table "Cell structure"

What have we learned?

A living organism consists of cells that have a rather complex structure. Outside, it is covered with a dense shell that protects the internal contents from the effects of the external environment. Inside there is a nucleus that regulates all ongoing processes and stores the genetic code. Around the nucleus is the cytoplasm with organelles, each of which has its own characteristics and characteristics.

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Divides all cells (or alive organisms) into two types: prokaryotes And eukaryotes. Prokaryotes are non-nuclear cells or organisms, which include viruses, prokaryotic bacteria and blue-green algae, in which the cell consists directly of the cytoplasm, in which one chromosome is located - DNA molecule(sometimes RNA).

eukaryotic cells have a nucleus in which there are nucleoproteins (histone protein + DNA complex), as well as others organelles. Eukaryotes include most of the modern unicellular and multicellular living organisms known to science (including plants).

The structure of eukaryotic organoids.

cell nucleus is the main and most complex organelle of the cell, so we will consider it

Everything in this world consists of different particles that make up a single picture, just like a living cell consists of organelles. The "unit of life" is covered with a protective barrier - a membrane that separates the external world from the internal contents. The structure of cell organelles is a whole system that needs to be sorted out.

eukaryotes and prokaryotes

In nature, there are a huge number of types of cells, only in the human body there are more than 200 of them, but only 2 types of cell organization are known - these are eukaryotic and prokaryotic. Both types mentioned have arisen through evolution. Eukaryotes and prokaryotes have a cell membrane, but that's where their similarities end.

Cells of the prokaryotic species are small in size and cannot boast of a well-developed membrane. The main difference is the absence of a core. In some cases, plasmids are present, which are a ring of DNA molecules. Organelles in such cells are practically absent - only ribosomes are found. Prokaryotes include bacteria and archaea. Monera - this is what was previously called single-celled bacteria that do not have a nucleus. Today, the term has fallen into disuse.

The eukaryotic type cell is much larger than prokaryotes and includes a structure called organelles. Unlike its simplest "relative", the eukaryotic cell has linear DNA, which is located in the nucleus. Another interesting difference between these two species is that mitochondria and plastids, which are inside the eukaryotic cell, are strikingly similar in their structure and vital activity to bacteria. Scientists have suggested that these organelles are descendants of prokaryotes, in other words, earlier prokaryotes entered into symbiosis with eukaryotes.

"Device" of a eukaryotic cell

Cell organelles are its small parts that perform important functions, such as storing genetic information, synthesis, division, and others.

Organelles include:

• cell membrane;
• Golgi complex;
• Ribosomes;
• microfilaments;
• Chromosomes;
• Mitochondria;
• Endoplasmic reticulum;
• microtubules;
• Lysosomes.

The structure of the organelles of animal, plant and human cells is the same, but each of them has its own characteristics. Animal cells are characterized by microfibrils and centrioles, while plant cells are characterized by plastids. A table of the structure of cell organelles will help to collect information together.

Some scientists attribute the cell nucleus to its organelles. The core is located in the center and has an oval or round shape. Its porous shell consists of 2 membranes. The shell has two phases - interphase and fission.

The cell nucleus has two functions - storage of genetic information and protein synthesis. Thus, the core is not only a "storage", but also a place where the material is reproduced and functions.

Table: structure of cell organelles

Cellular organelles - video

The smallest units of life. However, many highly differentiated cells have lost this ability. Cytology as a science At the end of the 19th century. The main attention of cytologists was directed to a detailed study of the structure of cells, the process of their division, and the elucidation of their role as the most important units that provide the physical basis of heredity and the process of development. Development of new methods. At first at...

As "beautiful May, which blooms only once, and never again" (I. Goethe), exhausted itself and was displaced by the Christian Middle Ages. 2. Cell as a structural and functional unit of the living. The composition and structure of the cell Modern cell theory includes the following provisions: 1. All living organisms are composed of cells. A cell is a structural, functional unit of a living, ...

0.05 - 0.10 Calcium Magnesium Sodium Iron Zinc Copper Iodine Fluorine 0.04 - 2.00 0.02 - 0.03 0.02 - 0.03 0.01 - 0.015 0.0003 0.0002 0.0001 0.0001 Cell content of chemical compounds Compounds (in %) Inorganic Organic Water Inorganic substances 70 - 80 1.0 - 1.5 Proteins Carbohydrates Fats Nucleic acids 10 - 20 0.2 ...

And these two organoids, as noted above, represent a single apparatus for the synthesis and transportation of proteins formed in the cell. Golgi complex. The Golgi complex is a cell organoid, named after the Italian scientist C. Golgi, who first saw it in the cytoplasm of nerve cells (1898) and designated it as a mesh apparatus. Now the Golgi complex is found in all plant cells and ...

Lesson type: combined.

Methods: verbal, visual, practical, problem-search.

Lesson Objectives

Educational: to deepen students' knowledge of the structure of eukaryotic cells, to teach how to apply them in practical classes.

Developing: to improve the ability of students to work with didactic material; develop students' thinking by offering tasks for comparing prokaryotic and eukaryotic cells, plant cells and animal cells with the identification of similar and distinctive features.

Equipment: poster "The structure of the cytoplasmic membrane"; task cards; handout (the structure of a prokaryotic cell, a typical plant cell, the structure of an animal cell).

Intersubject communications: botany, zoology, human anatomy and physiology.

Lesson plan

I. Organizational moment

Check readiness for the lesson.
Checking the list of students.
Presentation of the topic and objectives of the lesson.

II. Learning new material

Division of organisms into pro- and eukaryotes

The shape of the cells is extremely diverse: some are rounded, others look like stars with many rays, others are elongated, etc. Cells are also different in size - from the smallest, hardly distinguishable in a light microscope, to those perfectly visible to the naked eye (for example, fish and frog eggs).

Any unfertilized egg, including giant fossilized dinosaur eggs that are kept in paleontological museums, were also once living cells. However, if we talk about the main elements of the internal structure, all cells are similar to each other.

prokaryotes (from lat. pro- before, before, instead of and Greek. karyon- nucleus) - these are organisms whose cells do not have a nucleus limited by a membrane, i.e. all bacteria, including archaebacteria and cyanobacteria. The total number of species of prokaryotes is about 6000. All the genetic information of a prokaryotic cell (genophore) is contained in a single circular DNA molecule. Mitochondria and chloroplasts are absent, and the functions of respiration or photosynthesis, which provide the cell with energy, are performed by the plasma membrane (Fig. 1). Prokaryotes reproduce without a pronounced sexual process by dividing in two. Prokaryotes are able to carry out a number of specific physiological processes: they fix molecular nitrogen, carry out lactic acid fermentation, decompose wood, and oxidize sulfur and iron.

After an introductory conversation, students consider the structure of a prokaryotic cell, comparing the main features of the structure with the types of eukaryotic cells (Fig. 1).

eukaryotes - These are higher organisms that have a clearly defined nucleus, which is separated from the cytoplasm by a membrane (karyomembrane). Eukaryotes include all higher animals and plants, as well as unicellular and multicellular algae, fungi and protozoa. Nuclear DNA in eukaryotes is enclosed in chromosomes. Eukaryotes have cellular organelles limited by membranes.

Differences between eukaryotes and prokaryotes

- Eukaryotes have a real nucleus: the genetic apparatus of a eukaryotic cell is protected by a shell similar to the shell of the cell itself.
– Organelles included in the cytoplasm are surrounded by a membrane.

The structure of plant and animal cells

The cell of any organism is a system. It consists of three interconnected parts: membrane, nucleus and cytoplasm.

In the study of botany, zoology and human anatomy, you have already become familiar with the structure of various types of cells. Let's briefly review this article.

Exercise 1. Determine from Figure 2 which organisms and tissue types correspond to the cells under the numbers 1-12. What is the reason for their shape?

The structure and functions of organelles of plant and animal cells

Using figures 3 and 4 and using the Biological Encyclopedic Dictionary and textbook, students complete the table comparing animal and plant cells.

Table. The structure and functions of organelles of plant and animal cells

conclusions

1. The cell wall, plastids and the central vacuole are inherent only in plant cells.
2. Lysosomes, centrioles, microvilli are present mainly only in the cells of animal organisms.
3. All other organelles are characteristic of both plant and animal cells.

The structure of the cell membrane

The cell membrane is located outside the cell, delimiting the latter from the external or internal environment of the body. It is based on the plasmalemma (cell membrane) and the carbohydrate-protein component.

Cell wall functions:

- maintains the shape of the cell and gives mechanical strength to the cell and the organism as a whole;
- protects the cell from mechanical damage and the ingress of harmful compounds into it;
- performs recognition of molecular signals;
- regulates the exchange of substances between the cell and the environment;
- carries out intercellular interaction in a multicellular organism.

Cell wall function:

- represents an external frame - a protective shell;
- provides transport of substances (water, salts, molecules of many organic substances pass through the cell wall).

The outer layer of animal cells, unlike the cell walls of plants, is very thin and elastic. It is not visible under a light microscope and consists of a variety of polysaccharides and proteins. The surface layer of animal cells is called glycocalyx, performs the function of a direct connection of animal cells with the external environment, with all the substances surrounding it, does not play a supporting role.

Under the glycocalyx of the animal and cell wall of the plant cell, there is a plasma membrane that borders directly on the cytoplasm. The plasma membrane contains proteins and lipids. They are arranged in an orderly manner due to various chemical interactions with each other. Lipid molecules in the plasma membrane are arranged in two rows and form a continuous lipid bilayer. Protein molecules do not form a continuous layer, they are located in the lipid layer, plunging into it at different depths. Molecules of proteins and lipids are mobile.

Functions of the plasma membrane:

- forms a barrier that separates the internal contents of the cell from the external environment;
- provides transport of substances;
- provides communication between cells in the tissues of multicellular organisms.

Entry of substances into the cell

The surface of the cell is not continuous. In the cytoplasmic membrane there are numerous tiny holes - pores through which, with or without the help of special proteins, ions and small molecules can penetrate into the cell. In addition, some ions and small molecules can enter the cell directly through the membrane. The entry of the most important ions and molecules into the cell is not passive diffusion, but active transport, which requires energy. Transport of substances is selective. The selective permeability of the cell membrane is called semipermeability.

way phagocytosis inside the cell enter: large molecules of organic substances, such as proteins, polysaccharides, food particles, bacteria. Phagocytosis is carried out with the participation of the plasma membrane. In the place where the surface of the cell comes into contact with a particle of some dense substance, the membrane flexes, forms a depression and surrounds the particle, which in the "membrane capsule" is immersed inside the cell. A digestive vacuole is formed, and organic substances that have entered the cell are digested in it.

By phagocytosis, amoeba, ciliates, animal and human leukocytes feed. Leukocytes absorb bacteria, as well as a variety of solid particles that accidentally enter the body, thus protecting it from pathogenic bacteria. The cell wall of plants, bacteria and blue-green algae prevents phagocytosis, and therefore this pathway of substances entering the cell is not realized in them.

Liquid droplets containing various substances in a dissolved and suspended state also penetrate into the cell through the plasma membrane. This phenomenon was called pinocytosis. The process of fluid absorption is similar to phagocytosis. A drop of liquid is immersed in the cytoplasm in a "membrane package". Organic substances that enter the cell along with water begin to be digested under the influence of enzymes contained in the cytoplasm. Pinocytosis is widespread in nature and is carried out by the cells of all animals.

III. Consolidation of the studied material

What two large groups are all organisms divided into according to the structure of the nucleus?
What organelles are found only in plant cells?
What organelles are found only in animal cells?
What is the difference between the structure of the cell wall of plants and animals?
What are the two ways substances enter the cell?
What is the importance of phagocytosis for animals?