What are cells all made of, and what are cells made of?

The cell is the basic unit of structure and function of an organism. It is known that all living things except viruses are made up of cells, but viral life activities must also be in cells to be realized. Generally speaking, most microorganisms such as bacteria and protozoa are composed of a single cell, that is, a single-celled organism; Higher plants and higher animals are multicellular organisms.

Cells can be divided into two categories: prokaryotic cells and eukaryotic cells. However, it has also been suggested that there should be three categories, that is, the ancient karyotic cells, which originally belonged to prokaryotic cells, should be separated as a parallel category. The discipline that studies cells is called cell biology.

A molecule is the smallest particle that exists independently while maintaining the chemical properties of a substance. Molecules have a certain size and mass; There is a certain interval between molecules; Molecules are in constant motion; There is a certain force between molecules; Molecules can be made up of substances, and molecules can also be divided into smaller particles in chemical changes

Atom. Molecules can be converted into each other in the 3 states with the change of temperature. The properties of the same kind of molecule are the same, and the properties of different kinds of molecules are different.

The smallest molecule is an isotope of the hydrogen molecule, which is a hydrogen molecule without neutrons, called Euca, with a mass of 1Large molecules can have a relative molecular mass of more than several million. Molecules with a relative molecular mass of more than several thousand are called polymers.

A molecule is a tiny unit of matter, and it is the smallest particle that can exist independently and maintain all the original chemical properties of a substance.

Molecules are generally composed of smaller particle atoms, which can be divided into monoatomic molecules, diatomic molecules and polyatomic molecules according to the number of atoms that make up the molecule; According to the electrical structure, it can be divided into polar molecules and non-polar molecules The microstructure and shape of the molecules of different substances are different, and the ideal model of the molecule is to regard it as spherical, and its diameter is on the order of 10 -10m. The order of magnitude of molecular mass is about 10 -26kg.

The cell is the basic unit of structure and function of an organism.

The structure of a cell is mainly divided into three parts: cell membrane, cytoplasm and nucleus.

There is no unified definition of cell, and the more common term is that cell is the basic structural and functional unit of living organisms. It is known that all living things except viruses are made up of cells, but viral life activities must also be in cells to be realized.

Generally speaking, most microorganisms such as bacteria and protozoa are composed of a single cell, that is, single-celled organisms, and higher plants and higher animals are multicellular organisms. Cells can be divided into two categories: prokaryotic cells and eukaryotic cells, but some people have proposed that they should be divided into three categories, that is, the ancient karyotic cells that originally belonged to prokaryotic cells should be separated as a parallel category. The discipline that studies cells is called cell biology.

Cells are so small that they can only be seen under a microscope and come in a variety of shapes. It is mainly composed of the nucleus and cytoplasm, and has a cell membrane on the surface. Higher plants have a cell wall outside the cell membrane, plastids in the cytoplasm, chloroplasts and vacuoles in the body, and mitochondria.

Animal cells do not have a cell wall, and centrosomes are often present in the cytoplasm, while higher plant cells do not. Cells have functions such as locomotion, nutrition, and reproduction.

Cells were discovered in 1665 by the English scientist Robert Hooke (1635-1703). At that time, he used a homemade light microscope to observe the thin slices of the cork, and when he zoomed in, he found that the small space was named after the English cell, and the meaning of this English word itself has the usage of a small room one grid at a time, so it is not a new word.

Although he did not really see a unit of life (because there were no signs of life), later generations of scientists still believed that he was responsible for it, and generally regarded him as the first person to discover the cell. In fact, it was the Dutch biologist Leeuwenhoek who was the first to discover living cells.

There are various forms of composition, such as round, elongated, fusiformal, polygonal, etc.; There are spherical, flat, long cylindrical, etc. The size of the cells varies greatly, from animal cells to about 10 microns, while ramie bast fibroblasts are up to 55 centimeters long. Regardless of the morphology and size of cells, their basic structure can be divided into two main categories; Prokaryotic cells (mainly composed of two parts: cell membrane and cytoplasm) are composed of prokaryotes (bacteria, blue-green algae); Eukaryotic cells (mainly composed of three parts: cell membrane, nucleus, and cytoplasm).

Makes up eukaryotes (fungi, plants, animals). From here it can be seen that only eukaryotic cells have a nucleus. In 1935, the German scientist Ruska built the first electron microscope, which enabled scientists to use the electron microscope to observe many structures with different morphologies in the cytoplasm and nucleus.

What is a cell.

The most basic unit of living things is the cell. The cells are large and small, as large as a bird's egg, up to 10 centimeters, and as small as mycoplasma, which is only one ten-thousandth of a millimeter, which can be seen with an electron microscope.

Since the basic structure of living things is a cell, its structure determines its function. Cells are generally composed of a cell membrane, cytoplasm, and a silver-splitting nucleus. The lower prokaryotes do not have a nucleus, and the material equivalent to the nucleus is only distributed in the middle of the cytoplasm.

Outside the cell membrane of plants, there is also a hard cell wall. The main components of the cell membrane are proteins and lipids, which are mainly used to isolate the cell from the outside world, maintain relative stability, and communicate with the outside world about matter, energy and information. The cytoplasm is located between the cell membrane and the nucleus, and in addition to hyaluron, the main components are many organelles such as mitochondria and Golgi apparatus.

The role of cytoplasm is mainly to transport energy and provide a site for metabolism of new consumers, such as photosynthesis and respiration, glycolysis and fatty acid synthesis. The nucleus is made up of a nuclear membrane, nuclear fluid, nucleolus, and chromosomes. Chromosomes are found in nuclear fluids and are named because they are easily stained with basic dyes.

The number of chromosomes in the cells of each organism is fixed, such as 23 pairs of chromosomes in the nucleus of human somatic cells, 30 pairs in cattle, 22 pairs in rabbits, 21 pairs in wheat, and so on.

According to their basic structure, cells can be divided into two categories, one is prokaryotic cells and the other is eukaryotic cells. Protocells refer to the cells that make up lower organisms such as bacteria and cyanobacteria, which are relatively primitive, evolutionarily inferior, and relatively simple in structure, without typical nuclei and organelles.

Eukaryotic cells differ from prokaryotic cells in that they have a distinct nuclear structure and various organelles. Its structure is much more complex than that of prokaryotic cells, consisting of three basic parts: the cell membrane, the cytoplasm, and the nucleus. The vast majority of the more than 1.5 million living organisms are made up of eukaryotic cells.

The six elements of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur are the main elements that make up the protoplasm of cells. The organic matter that makes up the cell generally refers to a general term for carbonaceous compounds or hydrocarbons and their derivatives. Organic compounds composed of carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, etc. Sugars, fats, proteins, and nucleic acids are the most important organic compounds in living organisms and the most important organic compounds in cells.

The cell is actually a cell composed of the cell membrane, the nucleus, the endoplasmic reticulum, the Golgi apparatus, the mitochondria, the walnut and the cytoplasm.

It is mainly composed of the nucleus and cytoplasm.

Animal cell structures include cell membrane, cytoplasm, and nucleus. The cytoplasm of animal cells includes the cytoplasmic matrix and organelles. The organelles of animal cells include endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, lysosomes, centrosomes.

The outermost part of an animal cell is the cell membrane and has no cell wall; Animal cells do not contain chloroplasts in their cytoplasm and do not form vacuoles. Whereas, higher plant cells do not have centrosomes.

High three nets.

Animal cells and plant cells are different in their composition. Animal cells are composed of three parts: cell membrane, nucleus, and cytoplasm. Plant cells are composed of four parts: cell wall, cell membrane, nucleus, and cytoplasm.

Because animal cells do not have a cell wall, whereas plant cells have a cell wall.

Cells are the basic unit of structure and function of all living organisms, and the size and morphology of human cells have a great relationship with their environment and function. The structure of a cell mainly consists of three parts: the cell membrane, the cytoplasm, and the nucleus. When cells are observed under an electron microscope, they can be distinguished into membrane-phase structures and non-membrane-phase structures.

The cell membrane is a thin film on the surface of the cell, its thickness is about nanometers, and the chemical composition of the cell membrane is mainly lipids, proteins, and a certain amount of sugars. Under the electron microscope, the cell membrane can be seen that its structure is divided into three layers, the inner and outer layers are dark and dark, and the middle layer is light. Also, cytoplasm is the part between the cell membrane and the nucleus, including the organelles and the matrix.