What are the characteristics and biological significance of plant cell totipotency? Totipotency of plant cells means that each cell of a plant contains all the genetic information of the species, so it has the genetic ability to develop into a complete plant. Under appropriate conditions, any cell can develop into a new individual.
Using the totipotency of plant cells, rapid propagation can be realized, virus-free plants can be cultivated, and the continuation and protection of endangered plants can be realized, which has great economic and scientific benefits.
What is the biological significance of cell social communication biology?
(one of the six basic disciplines of natural science)
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Biology, abbreviated as biology, is one of the six basic disciplines of natural science. Study the structure, function, occurrence and development of living things. And the relationship between living things and their surroundings. Biology originated from natural history, experienced experimental biology and molecular biology, and entered the period of systematic biology.
What are the characteristics and biological significance of tricarboxylic acid cycle in Thai medicine? The characteristics of tricarboxylic acid recovery are as follows: ① it must be carried out under aerobic conditions; (2) It is the main way of productivity; ③ One-way reaction system; (4) Intermediate products must be continuously supplemented;
Biological significance of tricarboxylic acid cycle: ① it is the final metabolic pathway of three nutrients; (2) It is the hub of metabolism of three nutrients; (3) providing H+ and E for respiratory chain; (4) Providing small molecular precursors for the biosynthesis of some substances.
What is the biological significance of plant cell totipotency? Generalized totipotency refers to the potential or characteristics of a cell to develop into a complete organism. Totipotency of plant cells refers to the potential ability of cells with intact nuclei to differentiate and develop into complete plants under suitable conditions. Plant cells with intact nuclei carry all the genetic information necessary to form a complete plant. There are great differences in gene expression in different organs and tissues during growth and development, which is the result of changes in genetic information expression under the regulatory mechanism. Plant cell totipotency is an important theoretical basis of plant cell engineering and genetic engineering, and it has always been a hot topic in plant physiology, cell biology and molecular biology.
What is the act ring, its characteristics and biological significance? ACT (activated coagulation time of whole blood).
Act (Whole Blood Activated Coagulation Time) monitor is an objective and effective method to monitor coagulation time in clinical cardiopulmonary bypass surgery at home and abroad. The instrument can be used to measure the value of "ACT" during extracorporeal blood circulation in heart surgery, and the value of "ACT" during bypass surgery, PTCA, ICU/CCU, extracorporeal membrane oxygenation, hemofiltration and angioplasty, and thrombolysis in patients treated with heparin. Through the determination of ACT value, the measures of heparin anticoagulation and protamine antagonism needed by blood can be determined, which is one of the effective means to ensure the safety and success of heart surgery.
What is the tricarboxylic acid cycle? What are its characteristics and biological significance? Tricarboxylic acid cycle (TAC), also called TCA cycle, is a cycle in which acetyl-CoA and oxaloacetic acid condense to generate one molecule of citric acid containing three carboxylic acids, and finally generate one molecule of oxaloacetic acid, so it is also called citric acid cycle and Kribusz cycle, because it was put forward by Kribusz.
Tricarboxylic acid cycle is a ubiquitous metabolic pathway in aerobic organisms, with linear particle distribution. Because several main intermediate metabolites in this ring are citric acid containing three carboxyl groups, it is called tricarboxylic acid ring, also known as citric acid ring or TCA ring; Or named after the discoverer hans adolf krebs (1953 Nobel Prize winner in physiology or medicine).
The main significance of tricarboxylic acid cycle is the ultimate metabolic pathway of three nutrients (sugar, fat and amino acid), and it is also the hub of the metabolic relationship between sugar, fat and amino acid, and the main way for organisms to obtain energy.
Quoted from Baidu Encyclopedia.
Physiological significance of tricarboxylic acid cycle;
1, tricarboxylic acid cycle is the main way for the body to obtain energy, and also provides raw materials for the synthesis of some substances in the body. (such as providing succinyl CaA for heme. 1 molecule glucose only produces 2 molecules of ATP after anaerobic fermentation, while aerobic oxidation can produce 38 ATP (the numbers in different biochemical books are different, and most of them tend to be 32 ATP in recent years), of which 24 ATP are generated by tricarboxylic acid cycle. Under normal physiological conditions, many tissues and cells get energy from aerobic oxidation of sugar. Aerobic oxidation of sugar not only has high energy release efficiency, but also gradually releases energy and stores it in ATP molecules, so the utilization rate of energy is also high. )
2. Tricarboxylic acid cycle is a * * * co-metabolic pathway, through which sugar and protein are completely oxidized in the body. Acetyl coenzyme A, the initiator of the tricarboxylic acid cycle, is not only the product of the oxidative decomposition of sugar, but also comes from protein's metabolism of glycerol, acid and some amino acids. Therefore, the tricarboxylic acid cycle is actually the same way for the oxidation and energy supply of the three main organic substances in the body. It is estimated that two-thirds of organic matter in human body is decomposed by tricarboxylic acid cycle. )
3. Tricarboxylic cyclic sugars, lipids, protein and other amino acids are the hinge of metabolic connection and mutual transformation, and are the mutual transformation of three main organic substances in the body. (Because sugar and glycerol are metabolized in the body, they can generate intermediate products of tricarboxylic acid cycle such as α-ketoglutaric acid and oxaloacetic acid, which can be converted into certain amino acids; However, some amino acids can be converted into α -ketoglutaric acid and oxaloacetic acid by different ways, and then into sugar or glycerol by gluconeogenesis. Therefore, the tricarboxylic acid cycle is not only the ultimate same way of catabolism of three main organic compounds, but also their mutual changes. )
What is the biological significance of cell socialization? Urgent! Urgent! Urgent! There is no uniform definition of cells. In recent years, it is generally believed that cells are the basic unit of life activities. As we all know, all living things except viruses are composed of cells, but the life activities of viruses are bound to be reflected in cells. Generally speaking, most microorganisms such as bacteria and protozoa are composed of one cell, that is, a single-celled organism; Higher plants and animals are multicellular organisms. Cells can be divided into two types: prokaryotic cells and eukaryotic cells. However, it has also been suggested that it should be divided into three categories, that is, the ancient nucleus originally belonging to prokaryotic cells should be separated as a parallel category. The study of cells is called cell biology. The largest living cell in the world is ostrich eggs. Tiny cell
Plant cell structure: nucleus, cell wall, vacuole, mitochondria, cytoplasm and cell membrane. Edit this animal cell: cell membrane, cytoplasm, mitochondria and nucleus.
Basic * * * Edit this paragraph 1. On the surface of all cells, there is a biofilm consisting of phospholipid bilayer and protein, that is, cell membrane.
2. All cells contain two kinds of nucleic acids: DNA and RNA.
3. As a carrier of genetic information replication and transcription.
4. Ribosomes are machines synthesized by protein and exist in all cells without exception.
5. The proliferation of all cells can be divided into two ways. Editing the Basic Structure Observing the plant cells under the optical microscope, we can see that its structure is divided into the following four parts.
Cells under microscope 1. cytoderm
Located in the outermost layer of plant cells, it is a transparent thin wall. It is mainly composed of cellulose and pectin, with large pores and free penetration of substance molecules. Cell walls support and protect cells.
2. Cell membrane
The inner side of the cell wall is closely attached to an extremely thin membrane, which is called cell membrane. This film, which is composed of protein molecules and phospholipids, allows small molecules such as water and oxygen to pass freely, while some ions and macromolecules cannot pass freely. So it not only protects the inside of the cell, but also controls the entry and exit of substances: it prevents useful substances from seeping out of the cell at will, and it also prevents harmful substances from entering the cell easily.
Cell membrane is difficult to distinguish under optical microscope. Observing with electron microscope, we can know that the cell membrane is mainly composed of protein molecules and lipid molecules. In the middle of the cell membrane is a phospholipid bilayer, which is the basic skeleton of the cell membrane. On the outside and inside of phospholipid bilayer, there are many spherical protein molecules embedded in different depths of phospholipid bilayer or covered on the surface of phospholipid bilayer. Most of these phospholipid molecules and protein molecules have fluidity, so it can be said that the cell membrane has certain fluidity. This structural feature of cell membrane is very important for it to complete various physiological functions.
The basic structure of cell membrane: (1) lipid bilayer: phospholipid, cholesterol and glycolipid. There are about 109 lipid molecules on each animal membrane, that is, there are about 5x 106 lipid molecules on each square micron membrane. (2) Membrane proteins are divided into endogenous proteins and exogenous proteins. Intrinsic protein directly binds to the hydrophobic part of phospholipid through hydrophobic part, with polarity at both ends, which runs through the inside and outside of the membrane; The external protein is bound to the external end of the internal protein through a non-valence bond, or to the hydrophilic head of the phospholipid molecule. Such as vectors, specific receptors, enzymes and surface antigens. (3) Membrane sugar and sugar coating: glycoprotein and glycolipid.
3. Cytoplasm
The thick and transparent substance wrapped on the cell membrane is called cytoplasm. Some refractive particles can also be seen in the cytoplasm. Most of these particles have certain structure and function, similar to various organs of living things, so they are called organelles. For example, in the mesophyll cells of green plants, you can see many green particles, which are organelles called chloroplasts. Photosynthesis of green plants is carried out in chloroplasts. In the cytoplasm, one or several vacuoles are often seen, and the vacuoles are filled with liquid, which is called cell fluid. In mature plant cells, vacuoles merge into a central vacuole, accounting for more than half of the whole cell.
The cytoplasm is not frozen and static, but moves slowly. In cells with only one central vacuole, cytoplasm often flows around the vacuole, which promotes the transport of intracellular substances and strengthens the communication between organelles. Cytoplasmic movement is a life phenomenon that consumes energy. The more vigorous the life activity of cells, the faster the cytoplasmic flow, and vice versa. When cells die, the flow of cytoplasm stops.
In addition to chloroplasts, there are some organelles in plant cells, which have different structures and functions and * * * complete the life activities of cells. The structure of these organelles needs to be observed by electron microscope. The cell structure observed under electron microscope is called submicroscopic structure.
① Mitochondria
It is linear and granular, hence the name. On the linear particles, there are many kinds of particles related to respiration, that is, many kinds of respiratory enzymes. It is the place where cells breathe, through which they oxidize and decompose organic matter and release energy for the life activities of cells, so some people call mitochondria the "power station" or "power factory" of cells.
② Chloroplast
Chloroplast is an important organelle in green plant cells, and its main function is photosynthesis. Chloroplast consists of bilayer membrane, thylakoid and matrix. The thylakoid is a small flat thylakoid structure. On thylakoid membrane, there are pigments and enzymes necessary for photosynthesis. Many thylakoids are superimposed to form particles. Matrix is filled between particles, which contains enzymes related to photosynthesis. The matrix also contains DNA.
③ Endoplasmic reticulum
Endoplasmic reticulum (ER) is a reticular pipeline system composed of membranes in cytoplasm, which is widely distributed in cytoplasm matrix. It is connected with cell membrane and plays an important role in the synthesis and transportation of protein and other substances in cells.
There are two kinds of endoplasmic reticulum: one is smooth surface; The other is that many small particles are attached to it. Endoplasmic reticulum increases the membrane area in cells, and many enzymes attach to the membrane, which provides favorable conditions for normal chemical reactions in cells.
④ Golgi apparatus
Golgi apparatus is ubiquitous in plant cells and animal cells. It is generally believed that Golgi apparatus in cells is related to the formation of cell secretions. Golgi body itself has no function of synthesizing protein, but it can process and transport protein. Golgi apparatus is related to the formation of cell wall during plant cell division.
Ribosome 5
Ribosomes are oval granular bodies, some of which are attached to the outer surface of endoplasmic reticulum membrane, while others are free in the cytoplasmic matrix, which is an important basis for the synthesis of protein.
⑥ centrosome
Centrosomes exist in animal cells and some lower plant cells, and are called centrosomes because they are located near the nucleus. Each centrosome consists of two centrosomes arranged vertically to each other and perpendicular to the surrounding substances. The centrosome of animal cells is closely related to mitosis.
⑦ vacuole
Vacuoles are vesicular structures in plant cells. Vacuoles in mature plant cells are very large, accounting for 90% of the whole cell volume. There is a vacuole membrane on the surface of vacuole. There is cell fluid in vacuoles, which contains substances such as sugar, inorganic salts, pigments, protein, etc., and the concentration can reach a high level. Therefore, it plays a regulatory role in the environment where cells are located, which can keep cells in a certain osmotic pressure and keep them in an expanded state. Animal cells also have vesicles.
Eight lysosomes
Lysosomes are organelles with a single membrane sac structure in cells. It contains a variety of hydrolases and can decompose a variety of substances.
4. Nuclear
The cytoplasm contains an approximately spherical nucleus, which is composed of more viscous substances. The nucleus is usually located in the center of the cell. The nuclei of mature plant cells are often pushed to the cell edge by the central vacuole. There is a substance in the nucleus that is easily dyed dark by basic dyes such as magenta and hematoxylin. This substance is called chromatin. The substance used by organisms to transmit seeds and generations, that is, genetic material, is on chromatin. When cells undergo mitosis, chromatin becomes chromosomes.
It is composed of protoplasm and nucleus (or pseudonucleus) surrounded by membrane, which is the basic unit of organism structure and function, and also the basic unit of life activities. Cells can proliferate through division, which is the basis of individual development and systematic development of organisms. Cells are either independent living units, or multiple cells form cell groups or tissues, or organs and organisms; Cells can also divide and reproduce; Cell is the basic unit of heredity, and it has genetic totipotency (plant), so does animal nucleus.
Most cells have only one nucleus, and some cells contain two or more nuclei, such as muscle cells and liver cells. The nucleus can be divided into four parts: nuclear membrane, chromatin, nuclear fluid and nucleoli. The nuclear membrane is connected with endoplasmic reticulum, and chromatin is located between the nuclear membrane and nucleolus. Chromatin is mainly composed of protein and DNA. DNA is an organic macromolecule, also called deoxyribonucleic acid, which is the genetic material of living things. During mitosis, chromosomes are copied, and DNA is also copied into two parts, which are evenly distributed to two daughter cells, so that the number of chromosomes in offspring cells is constant, thus ensuring the stability of genetic characteristics of offspring. There is RNA, which is a single-stranded DNA in replication. It transmits protein and is called the messenger of DNA.
Comparison between animal cells and plant cells
Compared with plant cells, animal cells have many similarities, such as cell membrane, cytoplasm, nucleus and other structures. However, there are some important differences between animal cells and plant cells. For example, the outermost animal cell is a cell membrane, but there is no cell wall. The cytoplasm of animal cells does not contain chloroplasts and does not form central vacuoles.
In short, plants and animals are made up of cells. Cell is the basic unit of organism structure and function. Life Activities Editing The life activities of cells in this paragraph include:
1, cell growth
Results: Cells gradually enlarged.
2. Cell division
Results: The number of cells increased.
3. Cell differentiation
Results: Cell groups (tissues) with different functions were formed.