Amoebas: respiration, reproduction, cyst formation. Birth, breathing, growth, nutrition, reproduction, movement, dying (death) General characteristics of amphibians

Plan

Nutrition of microbes.

Respiration of microorganisms

Growth and reproduction of microbes.

Formation of pigments, photogenic and aromatic substances by microorganisms.

Bacterial enzymes.

Cultivation of bacteria.

Physiology studies the vital functions of microorganisms: nutrition, respiration, growth and reproduction. Physiological functions are based on continuous metabolism (metabolism).

The essence of metabolism consists of two opposite and at the same time interconnected processes: assimilation (anabolism) and dissimilation (catabolism).

During the assimilation process, nutrients are absorbed and used for the synthesis of cellular structures. During dissimilation processes, nutrients are decomposed and oxidized, releasing the energy necessary for the life of the microbial cell. As a result of the breakdown of nutrients, complex organic compounds are broken down into simpler, low-molecular ones. Some of them are removed from the cell, while others are again used by the cell for biosynthetic reactions and are included in the assimilation processes. All processes of synthesis and breakdown of nutrients are carried out with the participation of enzymes.

A feature of microorganisms is intensive metabolism. In one day, under favorable conditions, one microbial cell can process an amount of nutrients that is 30-40 times its mass.

Nutrition of microbes.

According to the type of nutrition, microbes are divided into autotrophs And heterotrophs. The former are capable of synthesizing complex organic substances from simple inorganic compounds. They can use carbon dioxide and other inorganic carbon compounds as a carbon source.

According to the method of assimilating nitrogen, microorganisms are divided into 2 groups: aminoautotrophs and amonoheterotrophs.

Aminoautotrophs - for protein synthesis, cells use molecular nitrogen from the air or absorb it from ammonium salts.

Aminoheterotrophs - obtain nitrogen from organic compounds - amino acids, complex proteins (all pathogenic microorganisms and most saprophytes).

According to the nature of the source of energy use, microorganisms are divided into phototrophs (use the energy of sunlight) and chemotrophs (use energy through the oxidation of inorganic substances) (microorganisms pathogenic to humans).

Microbial food type

Autotrophs Heterotrophs

(pathogenic and opportunistic microorganisms)

Facultative Obligate

Power mechanism. The penetration of various substances into the bacterial cell depends on the size and solubility of their molecules, pH of the medium, concentration, membrane permeability, etc. The main regulator of the entry of substances into the cell is the cytoplasmic membrane. The release of substances from the cell occurs through diffusion and with the participation of transport systems.

Penetration of nutrients into the microbial cell occurs in various ways:

1. Passive diffusion, i.e. the movement of substances through the thickness of the membrane, as a result of which the concentration of substances and osmotic pressure on both sides of the membrane are equalized. Nutrients can penetrate in this way when the concentration in the environment significantly exceeds the concentration of substances in the cell. This process is carried out without energy consumption.

2. Facilitated diffusion– penetration of nutrients into the cell through their active transport by special carrier molecules called permeases. This process occurs without the use of energy, since the movement of substances occurs from higher to lower concentrations.

3. Active transport nutrients are also carried out using permeases. This process requires energy. In this case, the nutrient can enter the cell if its concentration in the cell significantly exceeds the concentration in the medium.

4. The transported substance may be subject to chemical modification. This method is called radical transfer or translocation of chemical groups. This process is similar to active transport.

The release of substances from the microbial cell occurs either in the form of passive diffusion or in the process of facilitated diffusion with the participation of permeases.

For the growth of microbes on the nutrient media used for their cultivation, certain additional components are needed, compounds that the microbes themselves cannot synthesize. Such connections are called growth factors(amino acids, purines and pyrimidines, vitamins, etc.)

Respiration of microorganisms.

Breath(or biological oxidation) is a complex process accompanied by the release of energy necessary for the life of microbes. Bacteria, like higher animals, use oxygen for respiration. However, L. Pasteur proved the existence of such bacteria. For which the presence of free oxygen is destructive.

All microbes can be divided into three main groups according to the type of respiration:

- obligate(strict) aerobes(micrococci, tuberculosis bacteria, etc.). They can only grow in the presence of oxygen;

- obligate(strict) anaerobes(causative agents of gas gangrene, tetanus and botulism). They can only grow in the complete absence of oxygen;

- facultative anaerobes(most saprophytes and pathogenic microbes). They grow in both the presence and absence of oxygen.

Aerobic respiration occurs in the presence of oxygen. Anaerobic - in its absence.

Growth and reproduction of bacteria.

Height - this is an increase in the size of an individual. Reproduction is an increase in the number of individuals in a population. As a result of the growth and reproduction of microbes, their biomass increases. Bacteria reproduce by division. Actinomycetes and fungi reproduce by spores. Yeast reproduces by budding.

The rate at which microbes multiply varies. For most bacteria, the generation (doubling) period is on average 15-30 minutes, for example, for E. coli 15-17 minutes. Some microbes divide more slowly, such as spirochetes, once every 10 hours.

In liquid media, bacterial growth is characterized by the formation films on the surface, uniform cloudiness , or draft .

On solid nutrient media, bacteria form clusters of cells called colonies . The colonies formed are round in shape with smooth or uneven edges of varying consistency and color, depending on the pigment of the bacteria (blue, blood red, yellow). There are two types of colonies: rough with uneven edges (R-form) and smooth with smooth edges (S-form).

Reproduction. Cow and calf, horse and foal, oak tree and oak tree, hen and chicks are just a few examples of adult organisms and their young. Pay attention to the accuracy with which the offspring inherits the structure and behavior of the parents. The ability of organisms to produce offspring that have the characteristics of their parents is called reproduction (Fig. 117). This property of organisms ensures the continuity of life on Earth.

The ability of organisms to reproduce like themselves is called reproduction.

Rice. 118. Development of wheat

Growth and development. A grain of wheat planted in the soil in spring gives rise to a small sprout. Gradually, leaves appear on it, the stem thickens, and after a few months the sprout becomes an adult plant with an ear.

Mice are born naked, toothless, and after two months they become adults. As you can see, in both examples the size and mass of the organisms increased, that is, growth occurred. During the growth of the sprout of the plant and the pups, not only the mass and size of the organisms changed, but new formations appeared: leaves and ears in wheat (Fig. 118), fur and teeth in the pups (Fig. 119). Such gradual changes in organisms are called development.

Rice. 119. Development of baby mice

Height - gradual increase in size and weight of the body.

Development - changes in the structure of the body and its individual parts.

Nutrition and breathing. Organisms need nutrition.

Nutrition - This is the process of absorption of nutrients in the body.

In the process of nutrition, organisms receive a variety of organic and inorganic substances that ensure their growth, development and other vital processes. Material from the site

Substances necessary for life enter the body from the external environment. “Extra” substances, such as carbon dioxide and undigested food debris, are released into the external environment.

Organisms are inherent in breathing. Most organisms breathe oxygen, which is part of the air. In cells between oxygen and Various chemical phenomena constantly occur with organic substances. This releases energy that organisms use for growth, development, and movement.

Irritability. Organisms are able to respond to environmental influences. This is called irritability. For example, in bright light we squint our eyes or cover them with our palms; the hedgehog curls up into a ball if you touch it; the hare runs away upon noticing the approach of a predator.

Irritability is the body’s ability to respond to changes in environmental conditions.

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Nutrition. Protozoa feed primarily on dead organic matter, cells of bacteria, algae, and fungi, that is, they are heterotrophs.

Only certain representatives of protozoa, such as green euglena, are capable of photosynthesis.

All types of protozoa can absorb solutions of organic substances, some are capable of capturing solid particles (for example, cells of other organisms) by phagocytosis. The amoeba covers a particle of food with its pseudopods (Fig. 40).

This food particle, surrounded by a membrane, ends up inside the cell. This creates a digestive vacuole in which food is digested.

Undigested food remains are excreted anywhere in the cell or through special formations in its membrane.

Breath. Protozoa breathe oxygen dissolved in water or other liquid (for example, the host's blood).

The oxygen they absorb through the cell surface oxidizes organic matter. This releases the energy necessary to support the body’s vital processes.

Carbon dioxide produced during respiration is removed from the cell to the outside.

Main signs of living things

The simplest unicellular organisms belonging to the class of ciliates are distributed almost everywhere. From the cold ice of the North to the no less scorching icebergs of the South, these cute creatures are found in any stagnant water, one of the most important links in the food chain of the biocenosis. For an aquarist, ciliates are valuable as good food for newborn fry. But before introducing this living creature into your “underwater world”, it is worth getting acquainted with the reproduction, nutrition and vital activity of the microorganism.

Natural habitat and more

The smallest living creatures live in shallow bodies of still water. Slipper ciliates are so called for the similarity of the shape of the body, completely covered with cilia, with a lady's shoe. Cilia help animals move, feed, and even defend themselves. The smallest organism has a size of 0.5 mm; it is impossible to see the ciliate with the naked eye! An interesting way of moving in water is only with the rounded blunt end forward, but even with such a peculiar “walking”, the babies develop a speed of 2.5 mm/1 second.

Single-celled creatures have a two-nuclear structure: the first “large” nucleus controls nutritional and respiratory processes, monitors metabolism and movement, but the “small” nucleus is involved only in processes of sexual significance. The thinnest shell of increased elasticity allows the microorganism to be in its natural, clearly defined form, and also to move quickly. As such, movement is carried out through cilia, which act as “oars” and constantly push the shoe forward. By the way, the movements of all eyelashes are absolutely synchronous and coordinated.

Life activities: feeding, breathing, reproduction

Like all free-living microorganisms, the ciliate slipper feeds on the smallest bacteria and algae particles. Such a baby has an oral cavity - a deep cavity located in a certain place in the body. The mouth opening goes into the pharynx, and then the food goes straight into the vacuole for food digestion, and here the food begins to be processed by an acidic and then an alkaline environment. The microorganism also has a hole through which incompletely digested food remains exit. It is located behind the food opening and, passing through a special type of structure - powder, food remains are pushed out. The nutrition of the microorganism is adjusted to the limit, the shoe cannot overeat or remain hungry. This is perhaps one of nature's perfect creations.

The ciliate shoe breathes with all the integuments of its body. The released energy is enough to support the life of all processes, and unnecessary waste compounds, such as carbon dioxide, are also removed through the entire area of ​​the individual’s body. The structure of the ciliate slipper is quite complex, for example, contractile vacuoles, when overfilled with water and dissolved organic substances, rise to the extreme point of the plasma on the body and push out everything unnecessary. Freshwater inhabitants thus remove excess water, which constantly flows in from the surrounding space.

Microorganisms of this type can gather in large colonies to places where many bacteria accumulate, but react extremely sharply to table salt - they swim away.

Reproduction

There are two types of microorganism reproduction:

1. Asexual, which is a common division. This process occurs as the division of one ciliate slipper in two, with the new organisms having their own large and small nucleus. At the same time, only a small part of the “old” organelles passes into a new life; all the rest are quickly formed anew.
2. Sexual. This type is used only when there are temperature fluctuations, insufficient food and other unfavorable conditions. This is when the animals can separate into sexes and then turn into a cyst.

It is the second reproduction option that is most interesting:

1. Two individuals temporarily merge into one;
2. At the site of fusion, a certain channel is formed that connects the pair;
3. The large nucleus completely disappears (in both individuals), and the small nucleus is divided twice.

Plants, like all living organisms, constantly respire (aerobes). For this they need oxygen. It is needed by both unicellular and multicellular plants. Oxygen is involved in the life processes of plant cells, tissues and organs.

Most plants receive oxygen from the air through stomata and lentils. Aquatic plants consume it from water over the entire surface of their body. Some plants growing in wetlands have special respiratory roots that absorb oxygen from the air.

Respiration is a complex process that occurs in the cells of a living organism, during which the breakdown of organic substances releases the energy necessary for the vital processes of the organism. The main organic substance involved in the respiratory process is carbohydrates, mainly sugars (especially glucose). The intensity of respiration in plants depends on the amount of carbohydrates accumulated by the shoots in the light.

The entire process of respiration takes place in the cells of the plant organism. It consists of two stages, during which complex organic substances are broken down into simpler, inorganic substances - carbon dioxide and water. At the first stage, with the participation of special proteins that accelerate the process (enzymes), the breakdown of glucose molecules occurs. As a result, simpler organic compounds are formed from glucose and a little energy is released (2 ATP). This stage of the respiratory process occurs in the cytoplasm.

At the second stage, simple organic substances formed in the first stage, interacting with oxygen, are oxidized - they form carbon dioxide and water. This releases a lot of energy (38 ATP). The second stage of the respiratory process occurs only with the participation of oxygen in special cell organelles - mitochondria.

Respiration is the process of decomposition of organic nutrients into inorganic ones (carbon dioxide and water), which occurs with the participation of oxygen, accompanied by the release of energy that is used by the plant for vital processes.

C 6 H 12 O 6 + 6 O 2 = 6CO 2 + 6 H 2 O + Energy (38 ATP)

Respiration is the opposite process of photosynthesis

The breathing process involves the continuous consumption of oxygen day and night. The respiration process is especially intense in young tissues and organs of the plant. The intensity of respiration is determined by the needs of plant growth and development. A lot of oxygen is required in areas of cell division and growth. The formation of flowers and fruits, as well as damage and especially tearing off of organs, is accompanied by increased respiration in plants. At the end of growth, with yellowing of the leaves and, especially in winter, the intensity of respiration noticeably decreases, but does not stop.

Breathing, like nutrition, is a necessary condition for metabolism, and therefore for the life of the body.

Ø C1. In small rooms with an abundance of indoor plants, the oxygen concentration decreases at night. Explain why. 1) at night, with the cessation of photosynthesis, the release of oxygen stops; 2) in the process of plant respiration (they breathe constantly), the concentration of O 2 decreases and the concentration of CO 2 increases

Ø C1. It is known that it is difficult to experimentally detect plant respiration in the light. Explain why.

1) in the light in the plant, along with respiration, photosynthesis occurs, in which carbon dioxide is used; 2) as a result of photosynthesis, much more oxygen is produced than is used during plant respiration.

Ø C1. Why can't plants live without breathing? 1) in the process of respiration, plant cells absorb oxygen, which breaks down complex organic substances (carbohydrates, fats, proteins) into less complex ones; 2) this releases energy, which is stored in ATP and used for vital processes: nutrition, growth, development, reproduction and etc.

Ø C4. The gas composition of the atmosphere is maintained at a relatively constant level. Explain what role organisms play in this. 1) photosynthesis, respiration, fermentation regulate the concentration of O2, CO2; 2) transpiration, sweating, breathing regulate the concentration of water vapor; 3) the activity of some bacteria regulates the nitrogen content in the atmosphere.

The importance of water in plant life

Water is necessary for the life of any plant. It makes up 70-95% of the plant's wet body weight. In plants, all life processes occur using water.

Metabolism in the plant body occurs only with a sufficient amount of water. With water, mineral salts from the soil enter the plant. It ensures a continuous flow of nutrients through the conductive system. Without water, seeds cannot germinate and there will be no photosynthesis in green leaves. Water in the form of solutions that fill the cells and tissues of the plant provides it with elasticity and preservation of a certain shape.

• Absorption of water from the external environment is a prerequisite for the existence of a plant organism.

The plant obtains water primarily from the soil through the root hairs of the roots. The above-ground parts of the plant, mainly the leaves, evaporate a significant amount of water through the stomata. These moisture losses are regularly replenished as the roots constantly absorb water.

It happens that during the hottest hours of the day, the consumption of water by evaporation exceeds its supply. Then the plant’s leaves wither, especially the lower ones. During the night hours, when the roots continue to absorb water and the plant's evaporation is reduced, the water content in the cells is restored again and the cells and organs of the plant again acquire an elastic state. When transplanting seedlings, remove the lower leaves to reduce water evaporation.

The main way water enters living cells is its osmotic absorption. Osmosis - this is the ability of a solvent (water) to enter cellular solutions. In this case, the intake of water leads to an increase in the volume of fluid in the cell. The force of osmotic absorption with which water enters a cell is called sucking force .

The absorption of water from the soil and its loss through evaporation create a constant water exchange at the plant. Water exchange is carried out with the flow of water through all organs of the plant.

It consists of three stages:

absorption of water by roots,

its movement through the vessels of wood,

· evaporation of water by leaves.

Usually, with normal water exchange, as much water enters the plant as it evaporates.

The water current in the plant goes in an upward direction: from bottom to top. It depends on the strength of water absorption by the root hair cells below and on the intensity of evaporation above.

Root pressure is the bottom driver of water flow

the sucking power of the leaves is at the top.

A constant flow of water from the root system to the above-ground parts of the plant serves as a means of transporting and accumulating minerals and various chemical compounds coming from the roots in the body organs. It unites all the organs of the plant into a single whole. In addition, the upward flow of water in the plant is necessary for normal water supply to all cells. It is especially important for the process of photosynthesis in leaves.

ü C1. Plants absorb significant amounts of water throughout their lives. What are the two main processes?

Does life activity consume most of the water consumed? Explain your answer. 1) evaporation, ensuring the movement of water and dissolved substances and protection from overheating; 2) photosynthesis, during which organic substances are formed and oxygen is released

The abundance or deficiency of moisture in the cells affects all vital processes of the plant.

In relation to water, plants are divided into environmental groups

Ø Hydatophytes(from Greek hydatos- “water”, phyton- “plant”) - aquatic herbs (elodea, lotus, water lilies). Hydatophytes are completely submerged in water. The stems have almost no mechanical tissue and are supported by water. Plant tissues contain many large intercellular spaces filled with air.

Ø Hydrophytes(from Greek g idros- “aquatic”) - plants partially immersed in water (arrowleaf, reeds, cattails, reeds, calamus). They usually live along the banks of water bodies in damp meadows.

Ø Hygrophytes(from Greek gigra- “moisture”) - plants of humid places with high air humidity (marigold, sedge). 1) plants of wet habitats; 2) large bare leaves; 3) stomata do not close; 4) have special water stomata - hydothodes; 5) there are few vessels.

Ø Mesophytes(from the Greek mesos - “average”) - plants living in conditions of moderate moisture and good mineral nutrition (nivberry, lily of the valley, strawberry, apple tree, spruce, oak). They grow in forests, meadows, and fields. Most agricultural plants are mesophytes. They develop better with additional watering. 1) plants with sufficient moisture; 2) grow mainly in meadows and forests; 3) the growing season is short, no more than 6 weeks; 4) they survive dry times in the form of seeds or bulbs, tubers, rhizomes.

Ø Xerophytes(from Greek xeros- “dry”) - plants of dry habitats, where there is little water in the soil and the air is dry (aloe, cacti, saxaul). Among xerophytes, a distinction is made between dry and succulent. Succulent xerophytes with fleshy leaves (aloe, crassula) or fleshy stems (cacti - prickly pear) are called succulents. Dry xerophytes - sclerophytes(from the Greek scleros - “hard”) are adapted to strictly conserve water and reduce evaporation (feather grass, saxaul, camel thorn). 1) plants of dry habitats; 2) able to tolerate lack of moisture; 3) the surface of the leaves is reduced; 4) leaf pubescence is very abundant; 5) have deep root systems.

Leaf modifications arose in the process of evolution due to the influence of the environment, so they sometimes do not look like an ordinary leaf.

· spines in cacti, barberry, etc. - adaptations to reduce the area of ​​evaporation and a kind of protection from being eaten by animals.

· Mustache in peas, the ranks attach the climbing stem to a support.

· Juicy bulb scales, cabbage leaves store nutrients,

· Covering scales of buds- modified leaves that protect the shoot primordium.

In insectivorous plants ( sundew, bladderwort etc.) leaves - fishing devices. Insectivorous plants grow on soils poor in minerals, especially those with insufficient nitrogen, phosphorus, potassium and sulfur. These plants obtain inorganic substances from the bodies of insects.

Leaf fall- a natural and physiologically necessary phenomenon. Thanks to leaf fall, plants protect themselves from death during an unfavorable time of year - winter - or a dry period in a hot climate.

ü By shedding leaves, which have a huge evaporating surface, plants seem to balance the possible arrival and the necessary water consumption for the specified period.

ü Dropping leaves, plants are freed from various waste products accumulated in them resulting from metabolism.

ü Leaf fall protects branches from breaking off under the pressure of masses of snow.

But some flowering plants retain their leaves all winter. These are evergreen shrubs: lingonberry, heather, and cranberry. The small dense leaves of these plants, which weakly evaporate water, are preserved under the snow. Many herbs, such as strawberries, clover, and celandine, also overwinter with green leaves.

When calling some plants evergreen, we must remember that the leaves of these plants are not eternal. They live for several years and gradually fall off. But new leaves grow on the new shoots of these plants.

Plant propagation. Reproduction is a process that leads to an increase in the number of individuals.

In flowering plants there are

Ø vegetative reproduction, in which the formation of new individuals occurs from cells of vegetative organs,

Ø seed reproduction, in which the formation of a new organism occurs from a zygote that arises from the fusion of germ cells, which is preceded by a number of complex processes occurring mainly in flowers.

Reproduction of plants using vegetative organs is called vegetative.

Vegetative propagation, carried out with human intervention, is called artificial. Artificial vegetative propagation of flowering plants is resorted to in the case

§ if the plant does not produce seeds

§ accelerate flowering and fruiting.

Under natural conditions and in culture, plants often reproduce using the same organs. Reproduction very often occurs with the help of Cheren-kov. A cutting is a segment of any vegetative plant organ capable of restoring missing organs. Shoot segments with 1-3 leaves, in the axils of which axillary buds develop, are called stem cuttings . Under natural conditions, willows and poplars are easily propagated by such cuttings, and in cultivation - geraniums, currants...

Reproduction leaves occurs less frequently, but occurs in plants such as meadow core. In moist soil, an adventitious bud develops at the base of the broken leaf, from which a new plant grows. Usambara violet, some types of begonia and other plants are propagated by leaves.

Bryophyllum leaves form baby buds, which, falling to the ground, take root and give rise to new plants.

Many types of onions, lilies, daffodils, tulips multiply bulbs. A fibrous root system originates from the bottom of the bulb, and young bulbs called bulbs develop from some buds. kids. From each baby bulb a new adult plant grows over time. Small bulbs can form not only underground, but also in the axils of the leaves of some lilies. Falling to the ground, such baby bulbs also develop into a new plant.

Plants are easily propagated by special creeping shoots - mustache(strawberry, creeping tenacious).

Reproduction by division:

§ bushes(lilac) when the plant reaches a significant size, it can be divided into several parts;

§ rhizomes(irises) each segment taken for propagation must have either an axillary or apical bud

§ tubers(potatoes, Jerusalem artichokes), when there are not enough of them for planting in a certain area, especially if it is a valuable variety. The division of the tuber is carried out so that each part has an eye and so that the supply of nutrients is sufficient to reproduce a new plant;

§ roots(raspberries, horseradish) which produce new plants under favorable conditions;

§ root cones - tuber roots, which differ from a real root in that they do not have nodes and internodes. The buds are located only on the root collar or stem end, which is why in dahlias and tuberous begonias the root collar is divided into tuberous root formations.

Reproduction by layering. When propagating by layering, a shoot not separated from the mother plant is bent to the soil, the bark under the bud is cut and sprinkled with earth. When roots appear at the site of the incision and above-ground shoots develop, the young plant is separated from the mother plant and replanted. Currants, gooseberries and other plants can be propagated by layering.

Graft. A special method of vegetative propagation is grafting. Grafting is the transplantation of a part of a living plant, equipped with a bud, onto another plant with which the first is crossed. The plant that is grafted onto is called rootstock; plant that is grafted - scion.

In grafted plants, the scion does not form roots and is nourished by the rootstock, while the rootstock receives from the scion organic substances synthesized in its leaves. Grafting is most often used for propagating fruit trees, which have difficulty forming adventitious roots and cannot be propagated in any other way. Grafting can also be carried out by transplanting a piece of stem with one bud under the scion bark ( budding ) and by crossing scion and rootstock of equal thickness ( copulation ). When grafting, it is necessary to take into account the age and position of the cutting on the mother plant, as well as the characteristics of the scion. Thus, different methods of vegetative propagation show that in many plants a whole organism can be restored from a part.

Interconnection of organs. Despite the fact that all plant organs have a structure unique to them and perform specific functions, thanks to the conducting system they are connected together, and the plant functions as a complex, integral organism. Violation of the integrity of any organ necessarily affects the structure and development of other organs, and this influence can be both positive and negative. For example, removing the top of the stem and root promotes intensive development of the above-ground and underground parts of the plant, while removing leaves retards growth and development and can even lead to its death. Violation of the structure of any organ entails a violation of its functions, which affects the functioning of the entire plant.