A virus particle is an inert, static form of a virus. When virions are outside the cell, they do not multiply and no metabolic processes take place in them. All dynamic events begin only when the virus enters the cell. Even in a multicellular host, decisive events in viral infection occur at the cellular level. The spread of the virus occurs as a result of repeated cycles of interaction of the virus with cells and the dispersion of virions in the extracellular environment. (Fig. 57-60).
In virus-infected cells, a profound restructuring of the viral material, and often also of the host cell components, occurs. A new system emerges - the virus-cell complex. Reproduction of viruses is a multi-stage process that can be divided into seven stages:
Adsorption... It is the process of attaching viruses to the surface of a susceptible cell. Initially, virions are adsorbed by electrostatic interaction or by 167 an der Waals forces. This stage is reversible: the virus can be separated by simple shaking.
Injection... It is associated with the introduction (injection) into the cell of an infectious nucleic acid of a virus (like in phages) or the penetration of a whole viral particle into the cell, followed by "stripping" of the virus from the protein envelope and the release of an infectious nucleic acid.
Deproteinization... In the course of it, the carrier of the genetic information of the virus - its nucleic acid - is released. In bacteriophages, this process coincides with the previous stage.
Replicationviral nucleic acid molecules. Replication takes place at the expense of nucleotides accumulated in the host cell.
Synthesis of virus-specific structural proteins and enzymes... The synthesis process takes place in the ribosomes of the host cell.
Assembly (self-organization) of virus particles... For this it is necessary that the concentration of virion components reaches a high (critical) level. The components of the viral particle are synthesized separately and in different parts of the cell. 10 First, nucleic acids are complexed with a part of proteins and nucleoproteins are formed. The latter are covered with shells. These membranes often include some components of the cell membrane.
Lysis... In bacteria, cell decay occurs under the influence of phage enzymes, and in cells of higher organisms, by protruding the cell membrane and "pushing" viral particles into the environment.
Table17
|
Some of the most famous viral human diseases |
||||
|
Name illness |
Causative agent |
Affected areas of the body |
Way dissemination |
Vaccination type |
|
Mixovirus of one of three types - A, B and C - with varying degrees of virulence |
Respiratory tract: the epithelium lining the trachea and bronchi. |
Drip infection |
Killed virus: the strain of the killed virus must match the strain of the virus causing the disease |
|
|
Cold |
A wide variety of viruses, most commonly rhinoviruses (RNA viruses) |
Respiratory tract: usually only upper |
Drip infection |
Live or inactivated virus is administered by intramuscular injection; vaccination is not very effective as there are many different strains of rhinoviruses |
|
Smallpox virus (DNA virus), one of the smallpox viruses |
Airway, then skin |
Drip infection (possible contagious transmission through wounds on the skin). |
A live weakened (attenuated) virus is introduced into a scratch on the skin; does not apply now. |
|
|
Mumps (epidemic paratitis) |
Respiratory tract, then generalized infection throughout the body through the blood; the salivary glands are especially affected, and in adult men also the testes |
Drip infection (or contagious transmission by mouth with infectious saliva) |
Live attenuated virus |
|
|
Paramyxovirus (RNA virus) |
Respiratory tract (from oral cavity to the bronchi), then goes to the skin and intestines |
Drip infection |
Live attenuated virus |
|
|
Rubella measles (rubella) |
Rubella virus |
Airway, cervical lymph nodes, eyes and skin |
Drip infection |
Live attenuated virus |
|
Poliomyelitis (infantile paralysis) |
Poliomyelitis virus (picornavirus; RNA virus, three strains known) |
Pharynx and intestines, then blood; sometimes motor neurons of the spinal cord, then paralysis may occur |
Drip infection or through human feces |
Live attenuated virus is given orally, usually on a piece of sugar |
|
Yellow fever |
Arbovirus, i.e. arthropod-borne virus (RNA virus) |
Lining of blood vessels and liver |
Carriers - arthropods such as ticks, mosquitoes |
Live attenuated virus (it is also very important to control the number of possible vectors) |
R 
is. 57. Particles of influenza virus APR-8 (original strain). Viral particles are rounded. UEM-100 electron microscope. I took away. 27,000X2
Figure: 58. Trachea of \u200b\u200ba kitten 96 hours after infection with an allantoic culture of the influenza virus APR-8. Rough cytoplasm of the apical part of tracheal epithelial cells and adhesion of epithelial villi. Basophilic inclusions are located in groups in the cytoplasm of cells near the nucleus. Hematoxylineosin staining. I took away. 1000
Figure: 59. Rabbit trachea 96 hours after infection of the animal with influenza virus APR-8 (5th passage). Basophilic inclusions with an eosinophilic lining are visible in the cytoplasm of the tracheal epithelium; coarse ciliated villi. Hematoxylineosin staining. I took away. 1000
Fig. 60. Dog lung 96 hours after animal infection
influenza virus APR-8 (8th passage). In the cytoplasm of alveolar cells
basophilic inclusions with a zone of enlightenment around are visible. Coloration
hematoxylineosin. I took away. 1000.
Molecular composition of the cell
Elemental composition of the cell
Topic study plan
Section 1 THE TEACHING ABOUT THE CELL
Topic 1.1 Cell is an elementary living system. The chemical organization of the cell.
Basic concepts and terms on the topic: cell, macro-microelements, inorganic substances, biopolymers, monomers, carbohydrates, lipids, hormone, enzyme, vitamins, nucleic acids, ATP.
1.The concept of the science of cytology. A cell is an elementary living system.
2.Chemical composition cells:
a) the elemental composition of the cell;
b) inorganic substances of the cell: water, minerals;
c) organic substances: proteins, carbohydrates, lipids, nucleic acids, ATP.
Summary of theoretical questions:
1.Cytology (column
Posted on ref.rf
kytos - cell, logos - doctrine) - the science of the structure, function and development of the cell.
Cellconstitutes the basis of the structure, vital activity and development of all living forms - unicellular, multicellular and even non-cellular. Thanks to the mechanisms inherent in it, the cell provides metabolism, the use of biological information, reproduction, the properties of heredity and variability, thereby determining the qualities of unity and diversity inherent in the organic world. elementary living system.
2. All cells of animal and plant organisms, as well as microorganisms are similar in chemical composition. The cell contains several thousand substances that are involved in various chemical reactions. The similarity in the structure and chemical composition of different cells indicates the unity of their origin.
Macronutrients are part of organic compounds.
Trace elementsiodine (part of thyroxine, thyroid hormone), cobalt (vitamin B12), manganese, nickel, ruthenium, selenium, fluorine (tooth enamel), copper, chromium, zinc
Ultramicroelements - have a bactericidal effect, inhibit the reabsorption of water in the renal tubules, and affect enzymes. With its lack of selenium, cancers develop. The functions of ultramicroelements are still poorly understood.
Water - the most important component of the cell, determines the physical properties of the cell - volume, elasticity. Water dissolves substances participating in chemical reactions: it transfers nutrients, removes waste and harmful compounds from the cell.
Substances soluble in water, hydrophilic (from the Greek ʼʼhydros -water, phileoʼʼ - love) - alcohols, amines, carbohydrates, proteins, salts.
Water-insoluble hydrophobic (from the Greek "hydros" - water, "phobos" - fear, hatred) - fats, fiber.
Mineral salts provide stable indicators of osmotic pressure, transmission of nerve impulses, are carriers of an electric charge. For vital processes, of the cations included in the salt, the most important are: K +, Na +, Ca2 +, Mg2 + from anions: HPO4 2-, H2PO4 -, Cl -, HCO3 -. The strength and hardness of bone tissue is provided by calcium phosphate, and shellfish shells - by carbonate calcium.
Organic matter cells are represented by proteins, lipids, carbohydrates, nucleic acids, ATP, vitamins and hormones.
Protein are biopolymers, the monomers of which are amino acids. Amino acids contain an amino group, a carboxyl group and a radical. Proteins contain 20 basic amino acids. Amino acids combine with each other to form a peptide bond. A chain of more than 20 amino acids is commonly called a polypeptide or protein. Proteins form four main structures: primary, secondary, tertiary and quaternary
Proteins perform a number of functions in the cell: plastic (construction), catalytic (enzymatic), energy (the energy value of the breakdown of 1 g of protein is 17.6 kJ), signal (receptor), contractile (motor), transport, protective,regulatory, storing.
Carbohydratesare composed of carbon, hydrogen and oxygen. Complex - polymers with monomers in the form of monosaccharides (glucose, ribose, deoxyribose). Carbohydrates include glucose. animal starch-glycogen. Many carbohydrates are highly soluble.
Carbohydrates in the cell perform plastic (building), energy (energy value of the breakdown of 1 g of carbohydrates - 17.6 kJ), storage and support functions. Carbohydrates can also be found in complex lipids and proteins.
Lipidsare organic substances that are not soluble in water, but soluble in gasoline, ether, acetone. Of the lipids, the most common and known fats, as well as lecithin, cholesterol and vitamins A, D and hormones.
Lipids in the cell perform plastic (building), energy (the energy value of the breakdown of 1 g of fat - 38.9 kJ), storage, protective (depreciation) and regulatory (steroid hormones) functions .. Nucleic acidsare formed in the cell nucleus, which is why their name is connected (from the Latin “nucleus” -nucleus). these are biopolymers, the monomers of which are nucleotides. The nucleotide contains a nitrogenous base, a carbohydrate, and a phosphoric acid residue. There are two types of nucleic acids: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). DNA includes four types of nucleotides: adenine (A), thymine (T), guanine (G) and cytosine (C). The structure of DNA was discovered by F. Crick and D. Watson 1953ᴦ. The DNA molecule is a double-stranded helix. DNA determines the composition of cell proteins and the transmission of hereditary traits and properties from parents to offspring.
RNA includes four types of nucleotides: adenine (A), uracil (A), guanine (G) and cytosine (C). There are three types of RNA: informational (i-RNA), transport (t-RNA) and ribosomal (r-RNA) .RNA functions are associated with the formation of proteins characteristic of this cell
ATP (adenosine triphosphate) -universal biological energy accumulator in the cell. ATP is found in mitochondria, nucleus, chloroplasts, cytoplasm. With the help of ATP in the cell, substances are synthesized, the beating of flagella and cilia in protozoan cells.
Laboratory work / Practical exercises ʼʼ not provided ʼʼ
Molecular composition of a cell - concept and types. Classification and features of the category "Molecular composition of the cell" 2014, 2015.
MINISTRY OF EDUCATION OF THE REPUBLIC OF BELARUS
UO Grodno State University named after Y. Kupala
Leeds College
abstract
on the topic of: Cell chemistry
Completed by: Ermolovich Vitaly
Checked by: teacher of biology Yaroshko A.K.
Lida 2011
Plan
Introduction
Cell chemistry
Inorganic substances
Organic matter
Cellular theory of the structure of organisms
Metabolism and energy conversion in the cell
Conclusion
Literature
Introduction
A cell is an elementary unit of life on Earth. It has all the characteristics of a living organism: it grows, multiplies, exchanges substances and energy with the environment, and reacts to external stimuli.
The beginning of biological evolution is associated with the appearance on Earth cell forms life.
Single-celled organisms are cells that exist separately from each other. The body of all multicellular organisms - animals and plants - is built of more or less cells, which are a kind of building blocks that make up a complex organism. Regardless of whether a cell is an integral living system - a separate organism or is only a part of it, it is endowed with a set of features and properties common to all cells.
Purpose: to study the elementary unit of the structure of living organisms - the cell.
Main tasks:
Get to know inorganic and organic matter cells.
Consider the metabolism and energy conversion in the cell.
Study the cellular theory of the structure of organisms.
Cell chemistry
About 60 elements of the periodic system of Mendeleev, found in the inanimate nature, were found in the cells. This is one of the proofs of the commonality of animate and inanimate nature. In living organisms, the most abundant are hydrogen, oxygen, carbon and nitrogen, which make up about 98% of the cell mass. This is due to the peculiarities of the chemical properties of hydrogen, oxygen, carbon and nitrogen, as a result of which they turned out to be the most suitable for the formation of molecules that perform biological functions. These four elements are capable of forming very strong covalent bonds through the pairing of electrons belonging to two atoms. Covalently bonded carbon atoms can form the backbones of countless different organic molecules. Since carbon atoms easily form covalent bonds with oxygen, hydrogen, nitrogen, and also with sulfur, organic molecules become extremely complex and diverse in structure.
In addition to the four main elements in the cell in noticeable quantities (10 th and 100 th fractions of a percent) contain iron, potassium, sodium, calcium, magnesium, chlorine, phosphorus and sulfur. All other elements (zinc, copper, iodine, fluorine, cobalt, manganese, etc.) are in the cell in very small quantities and are therefore called trace elements.
Chemical elements are part of inorganic and organic compounds. Inorganic compounds include water, mineral salts, carbon dioxide, acids and bases. Organic compounds are proteins, nucleic acids, carbohydrates, fats (lipids), and lipoids. In addition to oxygen, hydrogen, carbon and nitrogen, they may contain other elements. Some proteins contain sulfur. Phosphorus is an integral part of nucleic acids. The hemoglobin molecule includes iron, magnesium is involved in the construction of the chlorophyll molecule. Microelements, despite their extremely low content in living organisms, play an important role in vital processes. Iodine is part of the thyroid hormone - thyroxine, cobalt - part of vitamin B 12 ... insulin, a hormone of the islet part of the pancreas, contains zinc. In some fish, copper takes the place of iron in the oxygen-carrying pigment molecules.
Inorganic substances
H 2 O is the most common compound in living organisms. Its content in different cells varies within a fairly wide range: from 10% in the enamel of the teeth to 98% in the body of a jellyfish, but on average it is about 80% of the body weight. The extremely important role of water in ensuring vital processes is due to its physical and chemical properties. The polarity of the molecules and the ability to form hydrogen bonds make water a good solvent for a huge number of substances. Most of the chemical reactions taking place in the cell can only take place in an aqueous solution. Water is also involved in many chemical transformations.
The total number of hydrogen bonds between water molecules varies with t . When ice melts, about 15% of hydrogen bonds are destroyed, at 40C - half. In the transition to the gaseous state, all hydrogen bonds are destroyed. This explains the high specific heat capacity of water. When t changes in the external environment, water absorbs or releases heat due to rupture or new formation of hydrogen bonds. In this way, fluctuations in t inside the cell are less than in the environment. The high heat of vaporization is the basis of an efficient heat transfer mechanism in plants and animals.
Water as a solvent takes part in the phenomena of osmosis, which plays