Which statements are true?
Topic 1. What is the difference between living and living
Bacteria are unicellular organisms.
All living organisms are mobile.
Plants are the main source of oxygen on Earth.
Only plants can grow.
Plants are able to actively move from one place to another.
Isolation occurs in all living organisms.
Plants and fungi belong to the same kingdom.
Reproduction is the reproduction of one's own kind.
Answers: 1,4,5,8,10
Topic 2. Chemical composition of cells
Oxygen, carbon, nitrogen, hydrogen are the most common elements in nature.
Oxygen, carbon, nitrogen, hydrogen are elements characteristic only of living nature.
Glucose, glycogen, sucrose, starch, fiber are types of carbohydrates.
Water is a good solvent.
Carbohydrates perform only a supporting function.
Fats serve as a reserve source of energy.
The similarity of the chemical composition and cellular structure of plants and animals speaks of the unity of the organic world.
Answers: 1,2,6,7,9,10
Topic 3. The structure of plant and animal cells
All cells of living organisms have a nucleus.
Cytoplasm is a viscous semi-liquid substance, the internal environment of the cell.
Ribosomes form complex carbohydrates.
The cell center provides the cell with energy.
Some viruses have a cellular structure.
The cell of any organism is covered on the outside with a cytoplasmic membrane.
Pinocytosis is the process of absorption of solid particles of a substance by the plasma membrane.
All cells of living organisms have plastids.
Chromosomes are in the nucleus.
Lysosomes provide the process of intracellular digestion.
Proteins are made in mitochondria.
Answers: 2,6,8,10,11
Topic 4. Cell division
The ability to divide is an important property of cells.
During mitosis, a cell goes through six major phases.
Mitosis produces four cells.
Meiosis produces two cells with a single set of chromosomes.
A chromatid is one half of a duplicated chromosome.
Meiosis consists of two consecutive divisions.
During meiosis, doubling of chromosomes occurs twice, i.e. before each division.
Paired chromosomes are called homologous.
Sex cells have half the number of chromosomes.
Answer: 1,2,6,7,9,10
Topic 5. Plant and animal tissues
All living organisms are made up of tissues.
Tissue is a group of cells that are similar in size, structure, and function.
Cells in tissues are connected by intercellular substance.
The educational tissue of the plant is located only at the top of the shoot.
The educational tissue of the plant is only in the embryo.
The role of the skeleton in the plant is performed by the main tissue.
Blood is connective tissue.
The integumentary tissue of plants forms the wood of trees.
The main properties of muscle tissue are excitability, contractility.
Nerve cells have numerous processes.
The main property of a nerve cell is excitability and contractility.
Answer: 2,3,5,6,7,9,10,12
Topic 6. Organs of flowering plants.
All plants have flowers.
An organ is a part of the body of an organism that performs certain functions.
The root holds the plant in the soil.
The dandelion has a fibrous root system.
Carrots and beans have a tap root system.
The shoot consists of a stem, leaves and buds.
The kidney is a rudimentary shoot.
Buds that contain the beginnings of a flower are called leaf buds.
All leaves have a leaf plate.
The stem can perform a storage function.
The main part of the flower is the corolla, as it attracts insects for pollination.
The pericarp is the overgrown and modified walls of the ovary.
The embryo consists of the germinal root, stalk and bud.
Answer: 2,3,5,6,7,9,10,12
Topic 7. Organs and systems of animal organs
Organs, united by a common work, make up the organ system.
Heart, kidneys, lungs - internal organs.
The excretory system provides gas exchange in the body.
The musculoskeletal system is formed by the skeleton.
The circulatory system carries substances dissolved in the blood throughout the body.
Animals breathe only with lungs.
The nervous system of vertebrates consists of the brain and nerves.
The coordinated work of the organs is ensured by the activity of the nervous system.
Answer: 1,2,5,8
Topic 9. What have we learned about the structure of living organisms
All living organisms are made up of cells.
Plants feed on ready-made organic substances.
The chemical composition of all living organisms is similar.
Proteins are the main source of energy.
Water is a good solvent.
Carbohydrates are carriers of hereditary information.
All cells have nuclei.
Proteins are made in ribosomes.
Viruses have a cellular structure.
The nucleus contains one or more nucleoli.
The ability to divide is an important property of every cell.
Cell division underlies the reproduction and development of organisms.
A chromatid is one half of a duplicated chromosome.
A tissue is a group of cells that are similar in structure and function.
Chloroplasts are found in the cells of the main tissue.
The main organs of plants are the flower and the root.
Beans have a tap root system.
The kidney is a rudimentary shoot.
The shoot consists of a stem and leaves.
The main parts of a flower are the stamens and the pistil.
The fruit develops from the ovary.
The embryo of a monocotyledonous plant contains one cotyledon.
Rice, rye, wheat are dicotyledonous plants.
Animals only breathe with their lungs
Topic 10. Nutrition and digestion
Only plants can directly absorb solar energy.
As a result of digestion, complex nutrients become available for absorption.
Animals consume ready-made organic matter.
The process of absorption of water and mineral salts from the soil by the root is called soil nutrition.
Coelenterates do not have a digestive system.
All animals are omnivores.
Hydras have only a mouth opening.
Enzymes are special chemicals that aid digestion.
Photosynthesis releases carbon dioxide as a by-product.
Answers:1,2,3,4,8,9
Topic 11. Breathing
All living organisms breathe.
Gas exchange in leaves occurs through lenticels.
Single-celled organisms breathe through the entire surface of the body.
Stomata are the respiratory organs of an earthworm.
Tracheal breathing is characteristic of insects.
Algae breathe through lenticels.
Only fish breathe with gills.
Only mammals have lungs.
There is no cutaneous respiration in terrestrial vertebrates.
A person breathes with lungs and skin.
Answers:1,3,5,10
Topic 12. Transport of substances in the body
All multicellular animals have red blood.
The earthworm has a closed circulatory system.
Blood is made up of plasma and blood cells.
The blood of all animals carries only oxygen.
The circulatory system of vertebrates is closed and consists of the heart and blood vessels.
Fish have a three-chambered heart.
Plant organic matter moves through sieve tubes.
When the water evaporates, the leaves of the plant cool.
Answers: 2,3,5,7,8
Topic 13. Selection
Plants and fungi do not have excretory systems.
The contractile vacuole is the excretory organelle of freshwater protozoa.
Flatworms do not have excretory organs.
The kidneys are the excretory organs of the worm.
The excretory system of fish consists of kidneys, ureters, bladder and a special opening.
Answers:1,2,5
Topic 14. Metabolism and energy
Metabolism occurs in all living organisms.
Only the leaves are involved in the metabolism of plants.
Plants take in oxygen, carbon dioxide, water, and mineral salts from the environment.
Photosynthesis produces organic matter and oxygen.
Metabolism consists of two opposite processes.
Only the respiratory and circulatory systems take part in the metabolism of animals.
Fish are warm-blooded animals.
Warm-blooded animals have a constant body temperature.
Snakes and frogs are warm-blooded animals.
With the cessation of metabolism, the death of a living organism occurs.
Answers: 1,3,4,5,8,10
Topic 15. The skeleton is the support of the body
All living organisms have an internal skeleton.
Some protozoa have an external skeleton.
The skeleton performs supporting and protective functions, and also serves as a place of attachment of internal organs.
Arthropods have an internal skeleton.
Mollusk shells are the outer skeleton.
Molting is characteristic of amphibians.
Vertebrates have an internal skeleton.
The skeleton of vertebrates consists of the skeleton of the head, trunk, and limbs.
Any tissue is a group of cells similar in structure and origin, as well as performing a common function. All fabrics are divided into 2 large groups:
- simple - consisting of one type of cell;
- complex - consisting of different types of cells, which, in addition to their main ones, also perform additional functions.
Morphological features of tissues (i.e., structural features) depend on the functions they perform. Plants have the following types of tissues:
- educational,
- coverslips,
- mechanical,
- conductive,
- basic.
Let's look at a brief description of each of them.
Educational
Educational tissues are also called meristems, which is translated from Greek. meristos means divisible. It is easy to guess that their main function is to ensure plant growth due to the almost constant division of cells entering the tissue.
The cells themselves are quite small, because they simply do not have time to grow. Among the main features of their structure, one can single out thin membranes, a tight fit of cells to each other, large nuclei, an abundance of mitochondria, vacuoles and ribosomes. Mitochondria act as energy suppliers for various cellular processes, and ribosomes synthesize the protein molecules necessary for the formation of new cells.
There are 2 subtypes of meristems:
- Primary - providing primary growth in length. It makes up the embryo of the seed, and in an adult plant this tissue is preserved in the tops of the shoots and the tips of the roots.
- Secondary - ensuring the growth of the stem in diameter. This group is divided into apical, lateral, intercalary and wound secondary meristems. They are composed of cambium and phellogen.
coverslips
Integumentary tissues form the surface of the body of plants, are found on all organs. Their main function is to ensure the body's resistance to mechanical stress and sharp temperature fluctuations, as well as protection from excessive evaporation of moisture and the penetration of pathogenic microorganisms.
These fabrics are divided into 3 main types:
- Epidermis (also called epidermis or skin) is the primary tissue of a single layer of small transparent cells that fit tightly together. It covers leaves and young shoots. The surface of this tissue has special formations called stomata, which regulate the processes of gas exchange and the movement of water through the body of the plant. It is also usually covered with a special cuticle or wax coating, which is an additional protection.
- The periderm is the secondary tissue that covers the stems and roots. It replaces the epidermis in perennials, less often in annuals. It consists of cork cambium (otherwise called phellogen) - a dead layer of cells, the walls of which are impregnated with a waterproof substance. It is formed by dividing and differentiating the phellogen inward and outward, as a result of which 2 layers are formed - phelloderm and phellem, respectively. Thus, the periderm has 3 layers: phellem (cork), phellogen, phelloderm. Since cork cells are impregnated with suberin, a fat-like substance that does not allow air and water to pass through, as a result, the contents of the cells die and they are filled with air. A dense cork layer is a reliable protection of plants from adverse external factors.
- Cork is a tertiary tissue that replaces cork. As a rule, it makes up the bark of trees and some shrubs. It is formed as a result of the fact that new areas of phellogen are laid in the deep tissues of the cortex, from which, accordingly, new layers of cork are formed. Because of this, the outer tissues are isolated from the central part of the stem, deform and die, and the surface of the stem is covered with dead tissue from several layers of cork and dead bark. Of course, a thick rind provides more protection than cork.
Mechanical
These tissues are composed of cells with thick membranes. They provide a kind of "frame", i.e., support the shape of the plant, make it more resistant to mechanical stress. Among the features of these tissues, one can single out a powerful thickening and lignification of the membranes, close adjacency of cells to each other and the absence of perforations in their walls. They are most strongly developed in the stems, where they are represented by wood and bast fibers, but are also present in the central part of the roots. There are 2 types of mechanical tissue:
- Kallenchyma - consists of living cells with unevenly thickened membranes, which can significantly strengthen young growing organs. In addition, the cells of this tissue are very easily stretched, so they do not interfere with the elongation of the plant.
- Sclerenchyma - consists of elongated cells with evenly thickened membranes, which, moreover, are often lignified, their contents die off in the early stages. The shells of these cells have a very high strength, so they form the tissues of the vegetative organs of land plants, constituting their axial support.
Conductive
Conductive tissues ensure the transfer and distribution of water and minerals throughout the body of the plant. There are 2 main types of such fabrics:
- Xylem (wood) is the main water-conducting tissue. Consists of special vessels - trachea and tracheids. The former are hollow tubes with through holes. The second - narrow, elongated dead cells with pointed ends and lignified shells. Xylem is responsible for the transport of liquid with minerals dissolved in it by an upward current - from the roots to the ground part of the plant. It also performs a supporting function.
- Phloem (bast) - represented by sieve tubes, provides a reverse, downward current: it carries the nutrients synthesized in the leaves to other parts of the plant, including the roots. It is in close relationship with xylem, forming together with it certain complex groups in plant organs - the so-called conductive bundles.
Main
The basic tissues (parenchyma), as the name suggests, form the backbone of plant organs. They are formed by living thin-walled cells and perform several functions, so they are divided into several varieties. In particular, these are:
- Assimilation - contain a large number of chloroplasts, respectively, are responsible for the processes of photosynthesis and the formation of organic substances. Basically, plant leaves are formed from these tissues, a little less of them is contained in young green stems.
- Storage - accumulate useful substances, including proteins and carbohydrates. These are tissues of roots, fruits, seeds, bulbs, tubers and stems of woody plants.
- Aquifers - store and store water. As a rule, these tissues form the organs of plants growing in dry and hot climates. They can be found both in leaves (for example, in aloe) and in stems (in cacti).
- Air-bearing - due to the large number of intercellular spaces filled with air, they transport it to those parts of the body whose communication with the atmosphere is difficult. They are characteristic of aquatic and marsh plants.
As we can see, plant tissues are no less diverse and complex than animals. They have achieved the greatest specialization in angiosperms: up to 80 types of tissues are isolated from them.
The totality of cells and intercellular substance, similar in origin, structure and functions, is called cloth. In the human body, they secrete 4 main tissue groups: epithelial, connective, muscular, nervous.
epithelial tissue(epithelium) forms a layer of cells that make up the integument of the body and the mucous membranes of all internal organs and cavities of the body and some glands. Through the epithelial tissue is the exchange of substances between the body and the environment. In the epithelial tissue, the cells are very close to each other, there is little intercellular substance.
Thus, an obstacle is created for the penetration of microbes, harmful substances and reliable protection of the tissues lying under the epithelium. Due to the fact that the epithelium is constantly exposed to various external influences, its cells die in large quantities and are replaced by new ones. Cell change occurs due to the ability of epithelial cells and rapid.
There are several types of epithelium - skin, intestinal, respiratory.
Derivatives of the skin epithelium include nails and hair. The intestinal epithelium is monosyllabic. It also forms glands. These are, for example, the pancreas, liver, salivary, sweat glands, etc. The enzymes secreted by the glands break down nutrients. The breakdown products of nutrients are absorbed by the intestinal epithelium and enter the blood vessels. The airways are lined with ciliated epithelium. Its cells have outward-facing mobile cilia. With their help, solid particles that have got into the air are removed from the body.
Connective tissue. A feature of the connective tissue is the strong development of the intercellular substance.
The main functions of connective tissue are nourishing and supporting. Connective tissue includes blood, lymph, cartilage, bone, and adipose tissue. Blood and lymph consist of a liquid intercellular substance and blood cells floating in it. These tissues provide communication between organisms, carrying various gases and substances. Fibrous and connective tissue consists of cells connected to each other by intercellular substance in the form of fibers. The fibers can lie densely and loosely. Fibrous connective tissue is present in all organs. Adipose tissue also looks like loose tissue. It is rich in cells that are filled with fat.
AT cartilage tissue the cells are large, the intercellular substance is elastic, dense, contains elastic and other fibers. There is a lot of cartilage tissue in the joints, between the bodies of the vertebrae.
Bone consists of bone plates, inside which cells lie. Cells are connected to each other by numerous thin processes. Bone tissue is hard.
Muscle. This tissue is formed by muscle. In their cytoplasm are the thinnest threads capable of contraction. Allocate smooth and striated muscle tissue.
The striated fabric is called because its fibers have a transverse striation, which is an alternation of light and dark areas. Smooth muscle tissue is part of the walls of internal organs (stomach, intestines, bladder, blood vessels). Striated muscle tissue is divided into skeletal and cardiac. Skeletal muscle tissue consists of elongated fibers, reaching a length of 10–12 cm. Cardiac muscle tissue, like skeletal tissue, has a transverse striation. However, unlike skeletal muscle, there are special areas where the muscle fibers are tightly closed. Due to this structure, the contraction of one fiber is quickly transmitted to neighboring ones. This ensures the simultaneous contraction of large sections of the heart muscle. Muscle contraction is of great importance. The contraction of the skeletal muscles ensures the movement of the body in space and the movement of some parts in relation to others. Due to smooth muscles, the internal organs contract and the diameter of the blood vessels changes.
nervous tissue. The structural unit of the nervous tissue is a nerve cell - a neuron.
A neuron consists of a body and processes. The body of a neuron can be of various shapes - oval, stellate, polygonal. The neuron has one nucleus, which is located, as a rule, in the center of the cell. Most neurons have short, thick, strongly branching processes near the body, and long (up to 1.5 m), and thin, and branches only at the very end processes. Long processes of nerve cells form nerve fibers. The main properties of a neuron are the ability to be excited and the ability to conduct this excitation along the nerve fibers. In the nervous tissue, these properties are especially pronounced, although they are also characteristic of muscles and glands. The excitation is transmitted along the neuron and can be transmitted to other neurons connected to it or to the muscle, causing it to contract. The importance of the nervous tissue that forms the nervous system is enormous. Nervous tissue is not only part of the body as a part of it, but also ensures the unification of the functions of all other parts of the body.
In any living or plant organism, tissue is formed by cells similar in origin and structure. Any tissue is adapted to perform one or several important functions for an animal or plant organism.
Types of tissues in higher plants
The following types of plant tissues are distinguished:
- educational (meristem);
- coverslips;
- mechanical;
- conductive;
- basic;
- excretory.
All these tissues have their own structural features and differ from each other in their functions.
Fig. 1 Plant tissues under a microscope
Educational tissue of plants
educational fabric- This is the primary tissue from which all other plant tissues are formed. It consists of special cells capable of multiple division. It is from these cells that the embryo of any plant consists.
This tissue is preserved in an adult plant. It is located:
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- at the bottom of the root system and at the tops of the stems (ensures the growth of the plant in height and the development of the root system) - the apical educational tissue;
- inside the stem (ensures the growth of the plant in width, its thickening) - lateral educational tissue;
Integumentary tissue of plants
Integumentary tissue refers to protective tissues. It is necessary in order to protect the plant from sudden changes in temperature, from excessive evaporation of water, from microbes, fungi, animals, and from all kinds of mechanical damage.
The integumentary tissues of plants are formed by cells, living and dead, capable of passing air, providing the gas exchange necessary for plant growth.
The structure of the integumentary tissue of plants is as follows:
- first is the skin or epidermis, which covers the leaves of the plant, stems and the most vulnerable parts of the flower; skin cells are alive, elastic, they protect the plant from excessive moisture loss;
- then there is a cork or periderm, which is also located on the stems and roots of the plant (where the cork layer forms, the skin dies off); cork protects the plant from adverse environmental influences.
Also, there is such a type of integumentary tissue as a crust. This is the most durable integumentary tissue, the cork in this case is formed not only on the surface, but also in depth, and its upper layers slowly die off. Essentially, the crust is made up of cork and dead tissue.
Fig. 2 Bark - a type of integumentary tissue of a plant
For the plant to breathe, cracks form in the crust, at the bottom of which there are special processes, lentils, through which gas exchange occurs.
plant mechanical tissue
Mechanical tissues give the plant the strength it needs. It is thanks to their presence that the plant can withstand strong gusts of wind and do not break under streams of rain and under the weight of fruits.
There are two main types of mechanical tissues: bast and wood fibers.
Conductive tissues of plants
The conductive fabric provides transportation of water with minerals dissolved in it.
This tissue forms two transport systems:
- ascending(from roots to leaves);
- descending(from leaves to all other parts of plants).
The ascending transport system consists of tracheids and vessels (xylem or wood), and the vessels are more perfect conducting means than tracheids.
In descending systems, the flow of water with photosynthesis products passes through sieve tubes (phloem or bast).
Xylem and phloem form vascular fibrous bundles - the "circulatory system" of the plant, which penetrates it completely, uniting it into one.
Main fabric
Underlying tissue or parenchyma- is the basis of the whole plant. All other types of tissues are immersed in it. It is a living tissue and it performs different functions. It is because of this that its different types are distinguished (information on the structure and functions of different types of the main tissue is presented in the table below).
| Types of main fabric | Where is it located in the plant | Functions | Structure |
| Assimilation | leaves and other green parts of the plant | promotes the synthesis of organic substances | made up of photosynthetic cells |
| Reserve | tubers, fruits, buds, seeds, bulbs, root crops | contributes to the accumulation of organic substances necessary for plant development | thin-walled cells |
| Aquifer | stem, leaves | promotes water retention | loose tissue made up of thin-walled cells |
| air-bearing | stem, leaves, roots | promotes air conduction through the plant | thin-walled cells |
Rice. 3 Basic tissue or plant parenchyma
excretory tissues
The name of this fabric indicates exactly what function it plays. These tissues contribute to the saturation of the fruits of plants with oils and juices, and also contribute to the release of a special aroma to the leaves, flowers and fruits. Thus, there are two types of this tissue:
- endocrine tissues;
- secretory tissues.
What have we learned?
For a biology lesson, students in grade 6 need to remember that animals and plants consist of many cells, which, in turn, line up in an orderly manner, form one or another tissue. We found out what types of tissues exist in plants - educational, integumentary, mechanical, conductive, basic and excretory. Each tissue performs its strictly defined function, protecting the plant or providing access to all its parts to water or air.
Topic quiz
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January 28, 2016According to biology, tissue is a special structure that ensures the functioning of any organism as a whole. What features of the structure must be possessed in order to perform such an important function?
What is tissue: biology will give an answer
According to the definition of the concept, a tissue is a group of cells that are similar in structure and function. Not all living organisms are formed by similar structures. So, viruses are non-cellular life forms, and all bacteria are single-celled.
Groups of specialized cells allow all physiological processes to be carried out more efficiently. That is why highly organized living objects consist of organs. This fact is proved by biology. Tissue is just a structure consisting of cells and forming organs.
Plant tissues
What is the fabric made of? Plant biology shows that not only from cells. Between them there is an intercellular substance that acts as a link. Plant tissues are practically devoid of it.
They are represented by the following types:
1. Integumentary:
The skin is a living tissue with special structures - stomata that serve for gas exchange;
Cork is a dead tissue in which the metabolism is carried out by lenticels.
2. Main - stores nutrients, carries out the process of photosynthesis, forms the basis of organs.
3. Mechanical - performs a supporting function.
4. Conductive - provides an ascending (water from the root) and a descending (organic matter from the leaves) current of substances.
5. Educational - when dividing, it restores the cells of any affected tissue, carrying out regeneration.
Animal tissues
A distinctive feature of this group of cells is the presence of a large amount of intercellular substance.
In animals, the following tissues are classified:
1. Epithelial - performs a protective function. It also forms glands and carries out metabolism. What is epithelial tissue made up of? Its biology is simple: small, tightly fitting cells of various shapes.
2. Connective - consists of large cells and a large amount of intercellular substance. It is the basis of the whole organism. Its varieties are blood, bone, cartilage and adipose tissue.
3. Muscular - represented by individual fibers capable of contraction - myofibrils. Thanks to them, it is possible to move the body in space and the movement of individual organs.
4. Nervous - connects the body with the environment, determines the presence of conditioned and innate reflexes. It consists of cells called neurons, and their processes - axons and dendrites. It is through them that information is transmitted from the receptors of sensory systems to the brain, and from there to the working organs.
The relationship of structure and functions
But most importantly, according to the science of biology, tissue is a group of cells whose functions are determined by their structure.
For example, small, closely spaced epithelial cells, practically devoid of intercellular substance, look like a shield. With such structural features, the function is obvious - protection. The connective tissue is arranged quite differently. Since it forms the basis of all organs, there should be a lot of it. This explains the presence of large cells and a large amount of intercellular substance. Especially a lot of it in the blood. This substance is known to everyone under the name of plasma. It contains shaped elements. Erythrocytes - red blood cells - transport oxygen from the lungs to organs and carbon dioxide in the opposite direction. Platelets - platelets, provide blood clotting. Leukocytes are colorless cells. They form immunity, helping the body to resist infectious diseases.
Fabrics and evolution
Biology did not immediately recognize what tissue is. After all, it was only with the invention of the light microscope that an amazing microscopic image of cells, and with it tissues, was revealed to man.
Lower plants, which include algae, do not have tissues. And even their multicellular representatives consisted of separate non-specialized cells, functionally unrelated to each other. Further, with a change in climatic conditions, the first plant natives to land appeared on Earth. According to biology, tissue is a necessary condition for their survival in new conditions. Mosses and club mosses first developed the mechanical tissues necessary for their spatial arrangement. And after - and conductive. This development led to the formation of real organs: a root and a shoot.
The most primitive multicellular animals also lack true tissues. We are talking about a representative of the type Intestinal freshwater hydra. Her body is formed by specialized cells: epithelial, muscle, genital, skin-muscular, glandular, etc. But they do not form clusters, but are scattered throughout the body.
Thus, the appearance of tissues was the beginning of the complication of the structure of living organisms, which makes it possible to better adapt to any conditions.
