Cells, like the building blocks of a house, are the building material of almost all living organisms. What parts do they consist of? What is the function of various specialized structures in the cell? You will find answers to these and many other questions in our article.
What is a cell
Cell is the smallest structural and functional unit of living organisms. Despite its relatively small size, it forms its own level of development. Examples of unicellular organisms are the green algae chlamydomonas and chlorella, the protozoa euglena, amoeba and ciliates. Their sizes are really microscopic. However, the function of a cell of an organism of a given systematic unit is quite complex. These are nutrition, respiration, metabolism, movement in space and reproduction.
General plan of cell structure
Not all living organisms have a cellular structure. For example, viruses are made up of nucleic acids and a protein coat. Plants, animals, fungi and bacteria are made up of cells. All of them are differentbuilding features. However, their general structure is the same. It is represented by a surface apparatus, internal contents - cytoplasm, organelles and inclusions. The functions of cells are due to the structural features of these components. For example, in plants, photosynthesis is carried out on the inner surface of special organelles called chloroplasts. Animals do not have these structures. The structure of the cell (the table "Structure and functions of organelles" examines in detail all the features) determines its role in nature. But for all multicellular organisms, the common thing is to ensure the metabolism and the relationship between all organs.
Cell structure: table "Structure and functions of organelles"
This table will help you get acquainted with the structure of cellular structures in detail.
| Cell structure | Building features | Functions |
| Core | Double-membrane organelle containing DNA molecules in its matrix | Storage and transmission of hereditary information |
| Endoplasmic reticulum | System of cavities, cisterns and tubules | Synthesis of organic substances |
| Golgi complex | Multiple pouches | Storage and transportation of organic matter |
| Mitochondria | Double-membrane rounded organelles | Oxidation of organic matter |
| Plastids | Double-membrane organelles,the inner surface of which forms outgrowths inside the structure | Chloroplasts provide the process of photosynthesis, chromoplasts give color to various parts of plants, leucoplasts store starch |
| Ribosome | Non-membrane organelles consisting of large and small subunits | Protein biosynthesis |
| Vacuoles |
In plant cells, these are cavities filled with cell sap, while in animals they are contractile and digestive |
Storage of water and minerals (plants). Contractile vacuoles ensure the removal of excess water and s alts, and digestive vacuoles - metabolism |
| Lysosomes | Round vesicles containing hydrolytic enzymes | Biopolymer breakdown |
| Cell center | Non-membrane structure consisting of two centrioles | Formation of the division spindle during cell cleavage |
As you can see, each cell organelle has its own complex structure. Moreover, the structure of each of them determines the functions performed. Only the coordinated work of all organelles allows life to exist at the cellular, tissue and organism levels.
Basic cell functions
Cell is a unique structure. On the one hand, each of its components plays its role. On the other hand, the functions of the cell are subject to a single coordinated mechanism of work. It is at this level of organization of life that the most important processes take place. One of them is reproduction. ATIt is based on the process of cell division. There are two main ways to do it. So, gametes are divided by meiosis, all the rest (somatic) - by mitosis.
Due to the fact that the membrane is semi-permeable, it is possible for various substances to enter the cell and in the opposite direction. The basis for all metabolic processes is water. Entering the body, biopolymers are broken down to simple compounds. But minerals are in solutions in the form of ions.
Cell inclusions
Cell functions would not be carried out in full without inclusions. These substances are the reserve of organisms for an unfavorable period. It can be drought, temperature drop, insufficient amount of oxygen. The storage functions of substances in the plant cell are performed by starch. It is found in the cytoplasm in the form of granules. In animal cells, glycogen serves as a storage carbohydrate.
What are fabrics
In multicellular organisms, cells that are similar in structure and function combine to form tissues. This structure is specialized. For example, all cells of the epithelial tissue are small, tightly adjacent to each other. Their form is very diverse. In this tissue, there is practically no intercellular substance. This structure resembles a shield. Due to this, the epithelial tissue performs a protective function. But any organism needs not only a "shield", but also the relationship with the environment. To carry out this function, in the epithelial tissue of animalsthere are special formations - pores. And in plants, the stomata of the skin or cork lentils serve as a similar structure. These structures carry out gas exchange, transpiration, photosynthesis, thermoregulation. And above all, these processes are carried out at the molecular and cellular level.
The relationship between the structure and functions of cells
The functions of cells are determined by their structure. All fabrics are a prime example of this. So, myofibrils are capable of contraction. These are muscle tissue cells that carry out the movement of individual parts and the whole body in space. But the connecting one has a different principle of structure. This type of tissue is made up of large cells. They are the basis of the whole organism. Connective tissue also contains a large amount of intercellular substance. Such a structure provides its sufficient volume. This type of tissue is represented by such varieties as blood, cartilage, bone tissue.
They say that nerve cells do not regenerate… There are many different views on this fact. However, no one doubts that neurons connect the entire body into a single whole. This is achieved by another feature of the structure. Neurons consist of a body and processes - axons and dendrites. According to them, information flows sequentially from the nerve endings to the brain, and from there back to the working organs. As a result of the work of neurons, the entire body is connected by a single network.
So, most living organisms have a cellular structure. These structures are the building blocks of plants, animals, fungi and bacteria. Generalcell functions are the ability to divide, perceive environmental factors and metabolism.
