What is the internal environment of a cell called: the concept of cytoplasm, hyaloplasm, cytosol. Life processes of a cell
>> Cellular structure body
§ 7. Cellular structure of the body
1. What is the structure of an animal cell?
2. What function do chromosomes perform?
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 participate in the biological oxidation of substances, due to which the energy necessary for the life of cells is released. These thread-like formations, barely visible in optical microscope, are called the energy stations of the cell.
Thanks to biological oxidation, complex organic substances break down and the energy released is used by cells for muscle contraction, heat production, and the synthesis of substances necessary for the formation of cell structures. Cells often contain microscopic vesicles, lysosomes, in which complex organic substances disintegrate and must be processed or destroyed.
Relationship between volume and cell surface.
The size of cells is limited, since with an increase in the volume and mass of a cell, its relative surface area decreases, and the cell can no longer receive required quantity nutrients and completely isolate the decomposition products. Therefore, having reached a certain size, it stops increasing in volume.
Cell division is a complex process (Fig. 12). It begins with the fact that around each DNA molecule its double is synthesized - the same molecule. A chromosome contains a pair of identical DNA molecules nearby, which will then become independent chromosomes of daughter cells.
Before division, the nucleus swells and increases in size. The chromosomes twist into a spiral and become visible under an optical microscope. The nuclear membrane disappears. The organelles of the cell center diverge to opposite poles of the cell, and a division “spindle” is formed between them.
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 to one centriole, and its counterpart to the other. Soon the DNA molecules begin to diverge, each towards its own pole. Two new sets are formed, consisting of identical chromosomes and identical genes. The chromosomes of daughter cells form balls. The nuclear envelope is synthesized around them. The chromosomes previously twisted into a spiral completely unwind and cease to be visible. After the formation of the nucleus, the organelles divide, the cytoplasm is “laced” into two halves, and two completely separate daughter cells are formed.
Life processes of a cell.
Metabolic processes take place in all cells without exception. Complex substances (characteristic of each type of cell) are formed from nutrients entering the cell, and cellular structures are formed. In parallel with the formation of new substances, biological oxidation processes occur organic matter- proteins, fats, carbohydrates. In this case, the energy necessary for the life of the cell is released. Decomposition products are removed beyond its boundaries.
Enzymes.
The synthesis and breakdown of substances occurs due to the action of enzymes. These are biological catalysts of a protein nature that accelerate the flow many times. 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. Thus, the enzyme catalase, located in the cell wall oral cavity, muscles, liver, is able to break down hydrogen peroxide. This 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 tubers 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 in cells and outside cells. When boiled, proteins coagulate and enzymes lose activity. They are also disabled by some chemical substances, for example salt heavy metals. (If you boil potatoes, the hydrogen peroxide decomposition reaction will not occur.)
Cell growth and development.
In the process of life, cell growth and development occur. Growth is an increase in the size and mass of a cell, and cell development is its age-related changes, including achieving its ability to fully perform its functions. For example, in order for a bone cell to create hard and durable bone matter, 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 contracts, and the glandular one secretes a secret.
Therefore, irritation is a process of influencing a 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 have the greatest excitability.
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 located?
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 cell organelles.
Kolosov D.V. Mash R.D., Belyaev I.N. Biology 8th grade
Submitted by readers from the website
Assignments for the School Olympiad in Biology
6th grade
Exercise 1 . The task includes 20 questions, each of them has 4 possible answers. For each question, select only one answer that you consider complete and correct.
Write down 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 ones 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 similar in structure, size and functions forms:
A) organ
B) fabric
B) virus
5. What are there root systems:
A) lateral and rod
B) fibrous and rod-like
B) main and fibrous
D) subordinate clauses and rod clauses
6. What is the name of the part of the body that performs certain functions:
A) organ
B) fabric
B) virus
7.
Water with organic and inorganic substances dissolved in it (vacuole contents) 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 germ of a bean seed consists of the following parts:
a) root, stem, bud;
b) embryonic root, stalk, bud, endosperm;
c) cotyledons, endosperm, bud;
d) cotyledons, germinal root, stalk, bud.
11.
Nutrients in wheat seed are found in:
a) spine;
b) cotyledon;
c) seed covers;
d) endosperm.
12.
The root developing from the radicle of the embryo is called:
a) main;
b) lateral;
c) subordinate clause;
d) fibrous.
13.
Root cap function:
a) continuous elongation of the root due to cell division;
b) conduction of water and minerals;
c) protecting 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) plant pressure 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 lower part of the stem;
d) from lateral and adventitious roots.
16.
Kidneys performing reserve function and developing after various damages plants are called:
a) axillary;
b) sleeping;
c) apical;
d) generative.
17.
A shoot whose internodes are poorly visible:
a) elongated shoot;
b) creeping shoot;
c) shortened shoot;
d) clinging shoot
18. Plant organs that carry out reproduction are called:
a) seed;
b) generative;
c) spore-bearing.
19. The science of botany studies:
A) all living organisms;
B) plants;
B) mushrooms.
20. Plants have the following life forms:
A) trees, shrubs, grasses;
B) trees, shrubs, herbs;
C) shrubs, herbs, shrubs;
D) shrubs, shrubs, herbs, trees
Task 2. A 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 occurs in chloroplasts non-stop throughout the day.
3. Root nutrition provides the plant with mineral salts and water, and air (leaf) nutrition is the main supplier of organic substances.
4. Green plants are autotrophs, that is, they are capable of independently creating organic substances from inorganic ones.
5. All plant organs consist of cells and tissues.
6. Only plants can absorb solar radiation energy.
7. By consuming inorganic substances: carbon dioxide, water and mineral salts, - the plant feeds.
8. In the fields, after harvesting, minerals absorbed by 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. A plant feeding itself with air is called aerial nutrition.
11. With the help of chlorophyll, organic substances (sugars) are formed from carbon dioxide and water in the leaf.
12. Autotrophs are 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 from sunlight received from space is stored by green plants in the form of carbohydrates, fats and proteins.
15. With the appearance 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 storing potatoes in a warm room, they shrink, 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, 20
Task 2.
1, 3, 4,5,6, 9,11,12, 14.
Task 3.
When storing potatoes in a warm room, they shrink as water evaporates from them.
When frozen, potatoes become sweet because starch turns into sugar when the temperature drops.
Internal environment cells
Inside the cell there is cytoplasm. It consists of a liquid part - hyaloplasm (matrix), organelles and cytoplasmic inclusions.
Hyaloplasma
Hyaloplasm is the main substance of the cytoplasm, fills all the space between the plasma membrane, the nuclear membrane and other intracellular structures. Hyaloplasm can be considered as complex colloidal system, capable of existing in two states: sol-like (liquid) and gel-like, which mutually transform into one another. In the process of these transitions, certain work is carried out and energy is expended. Hyaloplasm is devoid of any specific organization. Chemical composition hyaloplasma: water (90%), mineral ions, proteins (enzymes of glycolysis, metabolism of sugars, nitrogenous bases, proteins and lipids). Some cytoplasmic proteins form subunits that give rise to organelles such as centrioles and microfilaments.
Functions of hyaloplasm:
1) the formation of the 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 support for the internal arrangement of organelles;
3) ensuring intracellular movement of substances and structures;
4) ensuring adequate metabolism both inside 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 supply of nutrients from the outside (during cellular starvation) - drops of fat, starch or glycogen granules;
2) products that are subject to release from the cell, for example, granules of mature secretion in secretory cells (milk in lactocytes of the mammary glands);
3) ballast substances some cells that do not perform any specific function (certain pigments, such as lipofuscin in senescent cells).
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 surrounding external environment. In this sense biological systems are open .
Various organisms consume different types energy, and therefore they are divided into autotrophic and heterotrophic.
Autotrophic organisms(self-feeding) capable of absorbing energy inanimate nature. First of all, these are green plants, as well as brown and red algae that use sunlight for the process photosynthesis – formation of the organic substance glucose from inorganic water and carbon dioxide. Autotrophs also include blue-green algae (cyanes) and some bacteria capable of reactions chemosynthesis – synthesis of organic substances using 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 autotrophs seem to 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 huge role plant organisms as an intermediary in the energy supply of animals and humans. Humanity has not yet learned to get rid of this dependence, to obtain any energy directly from inanimate nature. And although Academician V.I. Vernadsky put forward such a scientific task, the matter did not advance beyond science fiction works and is unlikely to advance in the foreseeable future. Therefore, for biologists around the world, one of the priority tasks remains to understand in all details the mechanism of photosynthesis in order to maximally intensify it in plants and, if possible, reproduce it under artificial conditions.
The structure of ATP and its changes during metabolism
R energy metabolism reactions. Regardless of the initial source of energy, all organisms, both autotrophs and heterotrophs, first convert energy into a state convenient for further use. These are the so-called macroergic (energy-rich) bonds in molecules adenosine tri phosphoric acid– ATP . ATP molecules are formed from adenosine di phosphorus (ADP) or adenosine mono phosphoric (AMP) acid and free molecules of phosphoric acid, but with the inevitable absorption of external energy - solar or chemical (endothermic reaction). The amount of energy stored in a high-energy bond is an order of magnitude greater than in ordinary bonds, for example, inside a glucose molecule, therefore, in the composition 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 absolutely necessary, even into AMP and two phosphates), and the released energy is spent on one or another work - the synthesis of glucose in chloroplasts plant cells, synthesis of proteins and other macromolecules, transport of substances into and out of the cell, movement, etc. ADP (AMP) and phosphate can connect again, capturing the next portion of external energy, and then collapse and release energy into work. Cyclic transformations of ATP are repeated many times.
Thus, ATP acts as a universal carrier of energy 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 comes down to to understanding primary energy sources and the mechanisms of its translation into ATP. IN general view the situation is this: 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, plants need ATP to synthesize light, animals and humans need organic food.
Lightis primary source of energy,it is used in photosynthesis reactions in plants. At the end of the day, the photosynthesis reaction is quite simple:
6CO 2 + 6H 2 O + light energy → C 6 H 12 O 6 + 6O 2
Using 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 using 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 broken down, 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 expenditure. Direct use light is impossible here (evolution did not create such energy transitions), therefore some of the glucose is consumed as an energy substrate, that is, glucose becomes secondary source of energy. Glucose is broken down and releases 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 - transport of substances, cell movement, etc. Glucose is most efficiently 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 - “burning” of glucose. In a living cell
“burning” occurs slowly, step by step, so that energy is released in small portions, and most of it (about 55%) is used for the synthesis of ATP, the rest is dissipated in the form of heat. Complete oxidation one molecule of glucose provides synthesis 38 ATP molecules . Since we inhale oxygen for oxidation atmospheric air, then at the chemical level the oxidation of glucose by oxygen is called breathing. Main feature vegetable autotrophic cells - the ability to photosynthesis, which provides the first stage of building organic matter in the form of glucose. But respiration is also fully inherent in plants, since it is this process that extracts energy from glucose (as well as from fats and excess proteins), temporarily converts it into ATP and further into complex macromolecules. The same scheme, but with the removal of the photosynthesis reaction, corresponds to heterotrophic metabolism of animal cells. In this case, glucose (as well as other carbohydrates, fats, trophic proteins, etc.) enters the cell from outside in finished form. 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 building material. Thus, food for heterotrophs (that is, for you and me) has dual purpose– energy and plastic (construction).
There is an inextricable unity between plastic metabolism (anabolism) and energy metabolism (catabolism). Energy is absorbed from external environment, is converted into ATP, first of all, to carry out construction processes, to build 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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Biology Olympiad for 6th grade
Material developed and sent by: Victoria Viktorovna Maslova, biology teacher Municipal educational institution Dvoryanskaya secondary school, 403843, Dvoryanskoye village, Kamyshinsky municipal district, Volgograd region. Email address: [email protected]
OPTION "A"
For each of the tasks in option “A” there are four possible answers, 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 given below. Define this term.
1) vacuole 2) root 3) photosynthesis 4) mineral nutrition
2. What bacteria are considered “the planet’s nurses”?
1) rotting 2) acetic acid 3) lactic acid 4) nodule
3. The formation of organic substances from inorganic ones 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 reticulated leaf venation?
1) sphagnum mosses 2) conifers 3) dicotyledons 4) ferns
5. The structural features of which organ of flowering plants play a decisive role when combining them 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) membrane 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 types of root systems are there?
1) lateral and core 2) fibrous and core 3) main and fibrous 4) subordinate and core
10. What is the name of the part of the body that performs certain functions?
1) organ 2) phagocytosis 3) tissue 4) virus
