What is the name of the internal environment of the cell: the concept of cytoplasm, hyaloplasm, cytosol. Life processes of a cell
>> Cell structure organism
§ 7. Cellular structure of the body
1. What is the structure of an animal cell?
2. What is the function of chromosomes?
3. How does cell division occur?
External and internal environment of the body.
The external environment is the one in which the organism is located. A person lives in a gaseous environment, but can temporarily be in water, for example, while swimming.
Mitochondria are involved in the biological oxidation of substances, due to which the energy necessary for the life of cells is released. These filamentous formations, barely visible in optical microscope, are called energy stations of the cell.
Due to biological oxidation, complex organic substances decompose and the energy released in this case is used by cells for muscle contraction, heat generation, and the synthesis of substances necessary for the formation of cell structures. Cells often contain microscopic vesicles, lysosomes, in which complex organic substances decompose, to be processed or destroyed.
Relationship between volume and cell surface.
The cell size is limited, since with an increase in the volume and mass of the cell, its relative surface decreases, and the cell can no longer receive the right amount nutrients and isolate the complete decomposition products. Therefore, having reached a certain size, it ceases to increase in volume.
Cell division is a complex process (Fig. 12). It begins with the fact that around each DNA molecule its counterpart is synthesized - the same molecule. A pair of identical DNA molecules turns out to be nearby in a chromosome, which then become independent chromosomes of daughter cells.
Before division, the nucleus swells and increases in size. Chromosomes are twisted into a spiral and become visible in an optical microscope. The nuclear envelope disappears. The organelles of the cell center diverge to opposite poles of the cell, and between them a "spindle" of division is formed.
In the next phase of division, the chromosomes line up along the equator of the cell. Paired DNA molecules of each chromosome bind to the corresponding centrioles: one molecule with one centriole, and its twin with the other. Soon the DNA molecules begin to diverge, each to its own pole. Two new sets are formed, consisting of the same chromosomes and the same genes. Chromosomes of daughter cells form balls. Around them, the nuclear envelope is synthesized. Chromosomes twisted into a helix are completely untwisted and cease to be visible. After the formation of the nucleus, the division of organelles occurs, the cytoplasm is "laced" into two halves, and two completely separate daughter cells are formed.
Life processes of the cell.
In all cells, without exception, metabolic processes take place. From the nutrients entering the cell, complex substances are formed (characteristic for each type of cell), cellular structures are formed. In parallel with the formation of new substances, biological oxidation processes take place. organic matter- proteins, fats, carbohydrates. In this case, the energy necessary for the life of the cell is released. The decay products are removed outside of it.
Enzymes.
The synthesis and breakdown of substances occur due to the action of enzymes. These are biological catalysts of a protein nature, accelerating the flow many times over. chemical processes. Each enzyme acts only on certain compounds. They are called the substrate of this enzyme.
Enzymes are produced in both plant and animal cells. Sometimes their actions are similar. So, the enzyme catalase, located in the cell wall oral cavity, muscles, the liver, is able to break down hydrogen peroxide. It is a harmful compound produced in the body.
Let's do an experiment.
Pour hydrogen peroxide into a beaker and drop pieces of finely chopped potato into it. The liquid foams due to the formation of oxygen bubbles: 2H202 catalyst 2H2O + O2; poisonous hydrogen peroxide decomposes into harmless oxygen and water.
Enzymes act both inside and outside cells. When boiled, proteins coagulate and enzymes lose their activity. Disable them and some chemical substances, such as salt heavy metals. (If you boil potatoes, there will be no decomposition reaction of hydrogen peroxide.)
Growth and development of the cell.
In the process of life, the growth and development of cells occur. Growth is an increase in the size and mass of a cell, and development of a cell is its age-related changes, including the achievement of its ability to fully perform its functions. For example, in order for a bone cell to create a hard and durable bone substance, it must mature.
Rest and excitation of cells.
Cells can be in a state of rest or in a state of excitation.
When excited, the cell turns on work and performs its functions. Usually the transition to arousal is associated with irritation. So, in response to irritation nerve cell sends nerve impulses; muscle cell is reduced, and glandular - secretes a secret.
Therefore, irritation is the process of influencing the cell. It can be mechanical, electrical, thermal, chemical, etc. In response to irritation, the cell moves from a state of rest to a state of excitation, that is, active work.
The ability of a cell to respond to stimulation with a specific reaction is called excitability. Muscle and nerve cells are the most excitable.
Cell membrane, nucleus, cytoplasm, chromosomes, genes, DNA, RNA, nucleolus, organelles, endoplasmic reticulum, ribosomes, mitochondria, lysosomes, centrioles, metabolism, growth, development, enzymes.
1. In what environment are the cells of the human body?
2. What is the importance of the cell membrane?
3. What are the functions of the nucleus and nucleolus?
4. How many chromosomes do sex cells have - sperm and egg?
5. Name the organelles of the cell.
Kolosov D. V. Mash R. D., Belyaev I. N. Biology Grade 8
Submitted by readers from the website
Tasks of the school Olympiad in biology
6th grade
Exercise 1 . The task includes 20 questions, each of which has 4 possible answers. For each question, choose only one answer that you think is complete and correct.
Record the index of the selected answer.
1. What is the relationship between the term "plant" and one of the four terms below. Define this term.
A) vacuole
B) root
B) photosynthesis
2. The formation of organic substances from inorganic substances using solar energy occurs in plants in the process:
A) photosynthesis
B) breathing
B) evaporation
D) transport of substances
3. Name the internal environment of the cell, in which the nucleus and numerous organelles are located:
A) shell
B) cytoplasm
D) core
4. A group of cells that are similar in structure, size and functions, forms:
A) an organ
B) fabric
B) a virus
5. What are root systems:
A) side and rod
B) fibrous and rod
B) main and fibrous
D) accessory and rod
6. What is the name of the part of the body that performs certain functions:
A) an organ
B) fabric
B) a virus
7.
Water with organic and inorganic substances dissolved in it (vacuole content) is:
a) cytoplasm;
b) cell sap;
c) chlorophyll;
d) intercellular substance.
8.
education various shapes and colors that can give color various bodies plants are:
a) vacuoles;
b) intercellular spaces;
c) chromosomes;
d) plastids.
9.
A substance that gives a plant green color and playing a decisive role in the air nutrition of the plant is:
a) cell sap
b) intercellular substance;
c) chlorophyll;
d) cytoplasm.
10.
The bean seed germ consists of following parts:
a) root, stalk, kidney;
b) germinal root, stalk, kidney, endosperm;
c) cotyledons, endosperm, kidney;
d) cotyledons, germinal root, stalk, kidney.
11.
The nutrients in wheat seed are found in:
a) spine;
b) cotyledon;
c) integuments of the seed;
d) endosperm.
12.
The root that develops from the root of the embryo is called:
a) main;
b) side;
c) subordinate;
d) fibrous.
13.
Root Cap Function:
a) continuous elongation of the root due to cell division;
b) carrying water and minerals;
c) protection of the root tip from damage;
d) absorption of water and minerals.
14.
Root pressure is:
a) soil pressure on the root cap;
b) the force with which the root drives water into the stem;
c) the pressure of the plant on the soil;
d) soil pressure on the root hair.
15.
Root tubers are formed from:
a) main root
b) lateral roots;
c) from the main root and the lower part of the stem;
d) from lateral and adventitious roots.
16.
The kidneys that perform backup function and developing after various damage plants are called:
a) axillary;
b) sleeping;
c) apical;
d) generative.
17.
An escape in which internodes are poorly visible:
a) elongated shoot;
b) creeping escape;
c) shortened shoot;
d) clinging shoot
18. Plant organs that reproduce are called:
a) seed;
b) generative;
c) controversial.
19. The science of botany studies:
A) all living organisms
B) plants;
B) mushrooms.
20. Plants have the following life forms:
A) trees, shrubs, herbs;
B) trees, shrubs, herbs;
C) shrubs, herbs, shrubs;
D) shrubs, shrubs, herbs, trees
Task 2. Task to determine the correctness of judgments (17 judgments). Write down the numbers of the correct judgments.
1. The leaf is a special organ of air nutrition, since with the participation of the energy of sunlight in chlorophyll grains, organic substances are formed from carbon dioxide and water.
2. Difficult process Photosynthesis goes on in chloroplasts during the day without stopping.
3. Root nutrition provides the plant with mineral salts and water, while air (leaf) nutrition is the main supplier of organic matter.
4. Green plants are autotrophs, that is, they are able to independently create organic substances from inorganic ones.
5. All plant organs are made up of cells and tissues.
6. Only plants can absorb the energy of solar radiation.
7. Consuming inorganic substances: carbon dioxide, water and mineral salts, - the plant is fed.
8. In the fields, after harvesting, the minerals absorbed by the plants do not return to the soil.
9. In the forest, mineral salts absorbed by plants return to the soil with fallen leaves and needles.
10. Plant nutrition with air is called air nutrition.
11. With the help of chlorophyll, organic substances (sugars) are formed in the leaf from carbon dioxide and water.
12. Autotrophs - organisms capable of independently synthesizing organic substances from inorganic ones.
13. The role of green plants is called cosmic because they receive the energy of sunlight from space.
14. The energy of sunlight received from space is stored by green plants in the form of carbohydrates, fats and proteins.
15. With the advent of green plants on Earth, atmospheric oxygen was formed.
16. Oxygen is a substance necessary for photosynthesis and respiration of plants.
17. Metabolism is the nutrition and respiration of plants.
Task 3. Solve a biological problem.
When stored in a warm room, potatoes shrivel, and when frozen, they become sweet. Explain this phenomenon.
Answers to the School Olympiad in Biology
Exercise 1.
1c, 2a, 3c, 4b, 5b, 6a, 7b, 8d, 9c, 10d, 11d, 12a, 13c, 14b, 15d, 16b, 17c, 18b, 19b, 20g.
Task 2.
1, 3, 4,5,6, 9,11,12, 14.
Task 3.
When stored in a warm room, potatoes shrivel as water evaporates from them.
When frozen, potatoes become sweet, as when the temperature drops, starch turns into sugar.
Internal environment cells
Inside the cell is the cytoplasm. It consists of a liquid part - hyaloplasm (matrix), organelles and cytoplasmic inclusions.
Hyaloplasm
Hyaloplasm - the main substance of the cytoplasm, fills the entire space between the plasma membrane, the shell of the nucleus and other intracellular structures. Hyaloplasm can be considered as a complex colloid system, capable of existing in two states: sol-like (liquid) and gel-like, which mutually pass one into another. In the process of these transitions, certain work is carried out, energy is expended. Hyaloplasm is devoid of any specific organization. Chemical composition hyaloplasms: water (90%), mineral ions, proteins (enzymes of glycolysis, sugar metabolism, nitrogenous bases, proteins and lipids). Some cytoplasmic proteins form subunits that give rise to such organelles as centrioles, microfilaments.
Hyaloplasm functions:
1) the formation of a true internal environment of the cell, which unites all organelles and ensures their interaction;
2) maintaining a certain structure and shape of the cell, creating a support for the internal arrangement of organelles;
3) ensuring intracellular movement of substances and structures;
4) ensuring adequate metabolism both within the cell itself and with the external environment.
Inclusions
These are relatively unstable components of the cytoplasm. Among them are:
1) reserve nutrients that are used by the cell itself during periods of insufficient intake of nutrients from the outside (during cellular starvation) - drops of fat, starch or glycogen granules;
2) products that are to be released from the cell, for example, mature secretion granules in secretory cells (milk in lactocytes of the mammary glands);
3) ballast substances some cells that do not perform any specific function (some pigments, such as senescent cell lipofuscin).
Metabolism
The material essence of life is manifested, first of all, in the continuous exchange of substances and energy that occurs between a living system (cell, organism, biocenosis) and its external environment. In this sense biological systems are open .
Miscellaneous organisms consume different types energy, in connection with which they are divided into autotrophic and heterotrophic.
Autotrophic organisms(self-feeding) able to absorb energy inanimate nature. First of all, these are green plants, as well as brown and red algae, using sunlight for the process photosynthesis - the formation of organic glucose from inorganic water and carbon dioxide. Autotrophs also include blue-green algae (cyanides) and some bacteria capable of reactions chemosynthesis - synthesis of organic substances due to the energy of simple chemical reactions. Wherein primary energy (solar or chemical) is converted into the energy of chemical bonds of complex organic molecules, so that autotrophs, as it were, create their own food.
heterotrophic organisms(feeding at the expense of others) - humans, all animals, fungi, as well as many bacteria - receive food in the form of ready-made organic substances produced by autotrophs, mainly plants. As part of this food, they also receive energy contained in chemical bonds.
If the organic matter of food is broken down into more simple substances, energy is released. Essentially, heterotrophs receive the same solar energy, but converted by green plants into chemical energy. From here it is clear a huge role plant organisms as an intermediary in the energy supply of animals and humans. Mankind has not yet learned to get rid of this dependence, to receive any energy directly from inanimate nature. And although Academician V. I. Vernadsky put forward such a scientific problem, the matter has not progressed beyond fantastic works and is unlikely to advance in the foreseeable future. Therefore, for biologists around the world, one of the priority tasks remains to understand the mechanism of photosynthesis in all details in order to intensify it as much as possible in plants and, if possible, reproduce it under artificial conditions.
The structure of ATP and its change during metabolism
R energy metabolism reactions. Regardless of the initial source of energy, all organisms, both autotrophs and heterotrophs, first transfer energy to a state convenient for further use. These are the so-called macroergic (energy-rich) bonds in molecules adenosintri phosphoric acid– ATP . ATP molecules are formed from adenosine di phosphate (ADP) or adenosine mono phosphoric (AMP) acid and free molecules of phosphoric acid, but with the indispensable absorption of external energy - solar or chemical (endothermic reaction). The amount of energy stored in a macroergic bond is an order of magnitude greater than in ordinary bonds, for example, within a glucose molecule, therefore, as part of ATP, energy is conveniently stored and transported within the cell.
In places where this energy is consumed, ATP breaks down into ADP and phosphate (if necessary, even into AMP and two phosphates), and the released energy is spent on one or another job - the synthesis of glucose in chloroplasts. plant cells, the synthesis of proteins and other macromolecules, the transport of substances into and out of the cell, movement, etc. ADP (AMP) and phosphate can reconnect, capturing another portion of external energy, and then collapse and give energy to work. Cyclic transformations of ATP are repeated many times.
Thus, ATP acts as a universal energy carrier inside the cell, a kind of bargaining chip in energy payments for intracellular processes..
Pathways of anabolism and catabolism in the cell
The problem of cellular energy boils down to understanding primary energy sources and mechanisms of its transfer to ATP. AT general view the situation is as follows: in photosynthetic autotrophic organisms, the synthesis of ATP from ADP and phosphate is generated by solar energy, in heterotrophs, by energy from the oxidation of food products.
Thus, for ATP synthesis, plants need light, animals and humans need organic food.
Lightis primary source of energy,it is used in photosynthesis reactions in plants. Ultimately, the reaction of photosynthesis is quite simple:
6CO 2 + 6H 2 O + light energy → C 6 H 12 O 6 + 6O 2
With the help of light energy, a 6-carbon organic substance, glucose (monosaccharide), is synthesized from carbon dioxide and water, and oxygen is formed as an “extra” product, which goes into the atmosphere. In fact, this reaction is more complex, it consists of two stages: light and dark. First in the light with a special Mg-containing pigment chlorophyll water is split into oxygen and hydrogen, and the energy of hydrogen is transferred to the synthesis of ATP. Only then, in the dark stage, does hydrogen combine with carbon dioxide and glucose is formed. In this case, part of the ATP is split, giving energy to glucose.
glucose along with minerals, entering the plant from the soil (salts of nitrogen, sulfur, phosphorus, iron, magnesium, calcium, potassium, sodium, etc.), becomes the basis for more complex syntheses - polysaccharides, lipids, proteins, nucleic acids are formed, from which working structures are built cells. But these syntheses, like the synthesis of glucose, require energy costs. Direct use light is impossible here (evolution did not create such energy transitions), therefore some of the glucose is used as an energy substrate, that is glucose becomes secondary source of energy. Glucose is broken down and gives energy - first to the synthesis of ATP, and after the breakdown of ATP - to the biosynthesis of macromolecules.
A significant part of ATP, as mentioned above, is spent on other work - the transport of substances, cell movement, etc. Glucose is most effectively broken down with the participation of oxygen:
C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy
From a chemical point of view, this is complete oxidation - the “burning” of glucose. In a living cell
“Combustion” occurs slowly, in stages, so that energy is released in small portions, and most of it (about 55%) is used for ATP synthesis, the rest is dissipated in the form of heat. Complete oxidation one molecule of glucose provides synthesis 38 ATP molecules . Since oxygen for oxidation we inhale with atmospheric air, then at the chemical level, the oxidation of glucose by oxygen is called breath. Main feature vegetable autotrophic cells - the ability to photosynthesis, which provides the first stage in the construction of organic matter, in the form of glucose. But breathing is also fully inherent in plants, since it is this process that extracts energy from glucose (as well as from fats and excess proteins), transfers it temporarily into ATP and then into complex macromolecules. The same scheme, but with the removal of the photosynthesis reaction, corresponds to heterotrophic animal cell metabolism. In this case, glucose (as well as other carbohydrates, fats, trophic proteins, etc.) enters the cell from the outside in ready-made. Some of these materials are used for respiration (into the furnace, to extract energy through the synthesis of ATP), and some, after some alteration, for the synthesis of new macromolecules as a building material. In this way, food in heterotrophs (that is, with you and me) has dual purpose– energy and plastic (construction).
Between plastic metabolism (anabolism) and energy (catabolism) there is an inextricable unity. Energy is absorbed from external environment, is converted into ATP, primarily for the implementation of construction processes, for the construction of living matter. And the construction of living matter, that is, the synthesis of macromolecules from simple inorganic substances, is possible only with the absorption of external energy.
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Olympiad in biology for grade 6
Material developed and submitted by: Maslova Victoria Viktorovna, biology teacher Municipal educational institution Noble secondary school, 403843, Dvoryanskoye village, Kamyshinskiy municipal area, Volgograd region. Email address: [email protected]
OPTION "A"
For each of the tasks of option "A", four possible answers are given, of which only one is correct. Circle the number of this answer.
1. What is the relationship between the term "plant" and one of the four terms below. Define this term.
1) vacuole 2) root 3) photosynthesis 4) mineral nutrition
2. What bacteria are considered "planetary orderlies"?
1) decay 2) acetic acid 3) lactic acid 4) nodule
3. The formation of organic substances from inorganic substances using solar energy occurs in plants in the process
1) photosynthesis 2) respiration 3) evaporation 4) transport of substances
4. What class do they belong to flowering plants having a tap root system and reticulate leaf venation?
1) sphagnum mosses 2) coniferous 3) dicotyledons 4) ferns
5. The structural features of which organ of flowering plants play a decisive role when they are combined into classes?
1) seed 2) fruit 3) flower 4) leaf
6. Name the internal environment of the cell, in which the nucleus and numerous organelles are located
1) shell 2) plasma membrane 3) cytoplasm 4) nucleus
7. The number of chromosomes for each type of organism is constant. How many chromosomes does a person have?
1) 54 2) 78 3) 48 4) 46
8. A group of cells similar in structure, size and functions, forms:
9. What are the root systems
1) lateral and rod 2) fibrous and rod 3) main and fibrous 4) accessory and rod
10. What is the name of the part of the body that performs certain functions
1) organ 2) phagocytosis 3) tissue 4) virus
