Nitrification and microorganisms that carry it out. Nitrifier groups

Ammonia formed in soil, manure and water during the decomposition of organic matter is rather quickly oxidized to nitrous and then nitric acid. This process is called nitrification.

Until the middle of the 19th century, more precisely, before the works of L. Pasteur, the phenomenon of the formation of nitrates was explained as a chemical reaction of the oxidation of ammonia by atmospheric oxygen, and it was assumed that the soil played the role of a chemical catalyst. L. Pasteur suggested that the formation of nitrates is a microbiological process. The first experimental evidence of this assumption was obtained by T. Schlesing and A. Munz in 1879. These researchers passed wastewater through a long column of sand and CaCO3. During filtration, ammonia gradually disappeared and nitrates appeared. Heating the column or adding antiseptics stopped the ammonia oxidation.

However, neither the aforementioned researchers nor the microbiologists who continued to study nitrification were able to isolate cultures of causative agents of nitrification. Only in 1890-1892. SN Vinogradskiy, using a special technique, isolated pure cultures of nitrifiers. SN Vinogradskiy made the assumption that nitrifying bacteria do not grow on conventional nutrient media containing organic matter. This was quite correct and explained the failures of his predecessors. The nitrifiers turned out to be chemolithoautotrophs, very sensitive to the presence of organic compounds in the medium. These microorganisms were isolated using mineral nutrient media.

SN Vinogradskiy established that there are two groups of nitrifiers - one group oxidizes ammonia to nitrous acid (NH4 + → NO2-) - the first phase of nitrification, the other oxidizes nitrous acid to nitric acid (NO2- → NO3-) - the second phase of nitrification.

Bacteria of both groups currently belong to the Nitrobacteriaceae family. They are single-celled gram-negative bacteria. Among nitrifying bacteria, there are species with very different morphology - rod-shaped, ellipsoid, spherical, convoluted and lobed, pleomorphic. The cell sizes of different Nitrobacteriaceae species range from 0.3 to 1 µm in width and from 1 to 6.5 µm in length. There are mobile and immobile forms with polar, subpolar and peritrichial flagellation. They reproduce mainly by division, with the exception of Nitrobacter, which reproduces by budding. Almost all nitrifiers have a well-developed system of intra-cytoplasmic membranes, significantly different in shape and location in cells of different types. These membranes are similar to those of photosynthetic purple bacteria.

Bacteria in the first phase of nitrification are represented by five genera: Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosolobus, and Nitrosovibrio. The only microorganism studied in detail to date is Nitrosomonas europaea.

Nitrosomonas are short oval rods 0.8 - 1X1-2 microns in size. In liquid culture, Nitrosomonas go through a number of developmental stages. The two main ones are represented by a movable form and motionless zooglei. The mobile form has a subpolar flagellum or a bundle of flagella. In addition to Nitrosomonas, representatives of other genera of bacteria have been described that cause the first phase of nitrification.

The second phase of nitrification is carried out by representatives of the genera Nitrobacter, Nitrospira and Nitrococcus. The largest number of studies was carried out with Nitrobacter winogradskii, however, other species have also been described (Nitrobacter agilis, etc.).

Nitrobacter are elongated, wedge-shaped or pear-shaped, with a narrower end often bent into a beak. According to the studies of GA Zavarzin, reproduction of Nitrobacter occurs by budding, and the daughter cell is usually mobile, since it has one laterally located flagellum. The alternation in the development cycle of the mobile and immobile stages is known. Other bacteria have been described that cause the second phase of nitrification.

Nitrifying bacteria are usually cultured in simple mineral media containing ammonia or nitrites (oxidizable substrates) and carbon dioxide (the main source of carbon). These organisms use ammonia, hydroxylamine and nitrites as nitrogen sources.

Nitrifying bacteria develop at a pH of 6-8.6; the optimum pH is 7.5-8. At pH below 6 and above 9.2, these bacteria do not develop. The optimum temperature for the development of nitrifiers is 25-30 ° C. The study of the ratio of various strains of Nitrosomonas europaea to temperature showed that some of them have an optimum of development at 26 ° C or about 40 ° C, while others can grow quite rapidly at 4 ° C.

Nitrifiers are obligate aerobes. With the help of oxygen, they oxidize ammonia to nitrous acid (first phase of nitrification):

NH4 ++ 11 / 22O2 → NO2- + H2O + 2H +

And then nitrous acid to nitric (second phase of nitrification):

NO2- + 1 / 2O2 → NO3-

It is assumed that the nitrification process takes place in several stages. The first product of ammonia oxidation is hydroxyl, which is then converted to nitroxyl (NOH) or peroxonitrite (ONOOH), which, in turn, is further converted to nitrite or nitrite and nitrate.

Nitroxyl, like hydroxylamine, can apparently dimerize to hyponitrite or convert to nitrous oxide N2O, a by-product of the nitrification process.

In addition to the first reaction (the formation of hydroxylamine from ammonium), all subsequent transformations are accompanied by the synthesis of high-energy bonds in the form of ATP, which are necessary for the cells of microorganisms to bind CO2 and other biosynthetic processes.

The fixation of CO2 by nitrifiers is carried out through the reducing pentose phosphate cycle, or the Calvin cycle. As a result of carbon dioxide fixation, not only carbohydrates are formed, but also other compounds important for bacteria - proteins, nucleic acids, fats, etc.

According to the concepts that existed until recently, nitrifying bacteria were classified as obligate chemolithoautotrophs.

Data have now been obtained indicating the ability of nitrifying bacteria to use some organic matter. Thus, a stimulating effect on the growth of Nitrobacter in the presence of yeast autolysate nitrite, pyridoxine, glutamic acid and serine was noted. Therefore, it is assumed that nitrifying bacteria have the ability to switch from autotrophic to heterotrophic nutrition. Nitrifying bacteria, however, do not grow on conventional nutrient media, since a large amount of easily assimilated organic substances contained in such media retards their development.

The negative attitude of these bacteria to organic matter in laboratory conditions, it would seem, contradicts their natural habitat. It is known that nitrifying bacteria develop well, for example, in black soil, manure, compost, that is, in places where there is a lot of organic matter.

However, this contradiction can be easily eliminated by comparing the amount of easily oxidized carbon in the soil with the concentrations of organic matter that nitrifiers can withstand in crops. , and assimilable water-soluble organic substances make up no more than 0.1% of the total carbon. Consequently, nitrifiers do not meet large amounts of easily assimilated organic matter in the soil.

The staging of the nitrification process is a typical example of the so-called metabiosis, that is, this kind of trophic connections of microbes, when one microorganism develops after another on its waste. It has been shown that ammonia, a waste product of ammonifying bacteria, is used by Nitrosomonas, and the nitrites formed by the latter serve as a source of life for Nitrobacter.

The question arises about the importance of nitrification for agriculture. The accumulation of nitrates occurs with unequal intensity in different soils. However, this process is directly dependent on soil fertility. The richer the soil, the more nitric acid it can accumulate. There is a method for determining the nitrogen available to plants in the soil according to the indications of its nitrification capacity. Therefore, the rate of nitrification can be used to characterize the agronomic properties of the soil.

At the same time, during nitrification, only one nutrient for plants, ammonia, is converted into another form - nitric acid. Nitrates, however, have some undesirable properties. While the ammonium ion is absorbed by the soil, nitric acid salts are easily washed out of it. In addition, nitrates can be reduced as a result of denitrification to N2, which also depletes the nitrogen reserve of the soil. All this significantly reduces the utilization rate of nitrates by plants. In a plant organism, nitric acid salts, when used for synthesis, must be reduced, which is spent on energy. Ammonium is used directly. In this regard, the question is raised about approaches to artificially reducing the intensity of the nitrification process by using specific inhibitors that suppress the activity of bacteria - nitrifiers and harmless to other organisms.

It should be noted that some heterotrophic microorganisms are capable of nitrifying. Heterotrophic nitrifiers include bacteria from the genera Pseudomonas, Arthrobacter, Corynebacterium, Nocardia and some fungi from the genera Fusarium, Aspergillus, Penicillium, Cladosporium. It was found that Arthrobacter sp. oxidizes ammonia in the presence of organic substrates with the formation of hydroxylamine, and then nitrite and nitrate.

Some bacteria are capable of causing nitrification of nitrogen-containing organic substances such as amides, amines, hydroxamic acids, nitro compounds (aliphatic and aromatic), oximes, etc.

Heterotrophic nitrification occurs naturally (in soils, water bodies, and other substrates). It can acquire dominant importance, especially under atypical conditions (for example, with a high content of organic C - and N - compounds in alkaline soil, etc.). Heterotrophic microorganisms contribute not only to nitrogen oxidation under these atypical conditions, but can also cause the formation and accumulation of toxic substances; substances with carcinogenic and mutagenic effects, as well as compounds with chemotherapeutic action. Due to the fact that some of these compounds are harmful to humans and animals even at relatively low concentrations, their formation in vivo should be carefully studied.

). For the first time, pure cultures of these bacteria were obtained by S.N. Vinogradskiy in 1892, who established their chemolithoautotrophic nature. In the IX edition of Bergi's Guide to Bacteria, all nitrifying bacteria are separated into the Nitrobacteraceae family and divided into two groups, depending on which phase of the process they carry out. The first phase - the oxidation of ammonium salts to nitrous acid salts (nitrites) - is carried out by ammonium-oxidizing bacteria (genera Nitrosomonas, Nitrosococcus, Nitrosolobus, etc.):

NH4 + + 1.5O2 turns into NO2- + H2O + 2H +

NO2- + 1/2 * O2 turns into NO3-

The group of nitrifying bacteria is represented by gram-negative organisms, differing in the shape and size of cells, methods of reproduction, the type of flagellation of mobile forms, features of the cell structure, the molar content of GC-bases in DNA, and modes of existence.

All nitrifying bacteria are obligate aerobes; some species are microaerophiles. Most are obligate autotrophs, the growth of which is inhibited by organic compounds at concentrations common to heterotrophs. Using 14C compounds, it was shown that obligate chemolithoautotrophs can include some organic substances in the composition of cells, but to a very limited extent. The main source of carbon remains CO2, the assimilation of which is carried out in the reducing pentose-phosphate cycle. Only a few strains of Nitrobacter have shown the ability to grow slowly in a medium with organic compounds as a source of carbon and energy.

The nitrification process is localized on the cytoplasmic and intracytoplasmic membranes. It is preceded by the absorption of NH4 + and its transfer through the CPM using a copper-containing translocase. When ammonia is oxidized to nitrite, the nitrogen atom loses 6 electrons. It is assumed that at the first stage, ammonia is oxidized to hydroxylamine using monooxygenase, which catalyzes the addition of 1 O2 atom to the ammonia molecule; the second one interacts, probably, with NAD * H2, which leads to the formation of H2O:

NH3 + O2 + OVER * H2 goes over to NH2OH + H2O + OVER +

NH2OH + О2 goes into NO2- + Н2О + Н +

Electrons from NH2OH enter the respiratory chain at the cytochrome c level and then to terminal oxidase. Their transport is accompanied by the transfer of 2 protons across the membrane, leading to the creation of a proton gradient and the synthesis of ATP. Hydroxylamine in this reaction is likely to remain bound to the enzyme.

The second phase of nitrification is accompanied by the loss of 2 electrons. Oxidation of nitrite to nitrate, catalyzed by the molybdenum-containing enzyme nitrite oxidase, is localized on the inner side of the CPM and proceeds as follows:

NO2- + H2O transforms into NO3- + 2H + 2e

Electrons enter cytochrome a1 and through cytochrome c to terminal oxidase aa3, where they are accepted by molecular oxygen (Fig. 98, B). In this case, a 2H + transfer occurs through the membrane. The flow of electrons from NO2- to O2 takes place with the participation of a very short segment of the respiratory chain. Since Eo of the NO2 / NO3– pair is +420 mV, the reducing agent is formed in the process of energy-dependent back transfer of electrons. The high load on the terminal portion of the respiratory chain explains the high content of cytochromes c and a in nitrifying bacteria.

Many chemoorganoheterotrophic bacteria belonging to the genera Arthrobacter, Flavobacterium, Xanthomonas, Pseudomonas, and others are capable of oxidizing ammonia, hydroxylamine, and other reduced nitrogen compounds to nitrites or nitrates. The process of nitrification of these organisms, however, does not lead to the receipt of energy by them. The study of the nature of this process, called heterotrophic nitrification, showed that, possibly, it is associated with the destruction of the

All living things need food. For some, the source of energy is sunlight, others use chemical reactions for this purpose, and still others receive nutrition from the first two groups. The first group includes all plants, the representatives of the second are nitrifying bacteria, the third group includes all animals, including you and me.

All green plants and many bacteria can themselves produce organic nutrients from inorganic ones (water, carbon dioxide, etc.). This group of living organisms is called autotrophs (from Latin "self-feeding"), or producers, and is the first link in the food chain.

Organisms that receive energy from sunlight during photosynthesis are called phototrophs. Nitrifying bacteria belong to the group of microorganisms that use the energy of chemical oxidation reactions as a source of nutrition. Such organisms are called chemotrophs.

Nitrifying bacteria (chemotrophs) do not assimilate organic matter in soil or water. On the contrary, they synthesize the building material to create a living cell.

Substances obtained by the nitrifying bacteria from soil and water are oxidized, and the resulting energy is used to synthesize complex organic molecules from water and carbon dioxide. This is the so-called chemosynthesis process.

Chemosynthetic organisms, like all autotrophs, do without the necessary nutrients from the outside, they produce them on their own. However, unlike green plants, nitrifying bacteria do not even need sunlight to feed.

There are organisms that use electricity to generate energy. Recently, a group of Japanese scientists published the results of a study of bacteria living near deep-sea hot springs. When the water flow frictions against rock ledges at the bottom, a weak charge of electricity is formed, which was used by the studied bacteria to obtain food.

What is needed for plant nutrition?

Nitrifying bacteria inhabiting the soil by oxidation decompose ammonia, which is formed from decay of organic matter to nitrous acid. Other bacteria oxidize (add oxygen with the release of energy) nitrous acid to nitric acid. In turn, both of these acids, with the help of minerals from the soil, create salts and phosphates for plant nutrition.

In addition, the nitrogen contained in the environment is necessary for nutrition. However, the plants are not able to extract it on their own. Nitrogen-fixing bacteria come to the rescue. They assimilate nitrogen in the air and convert it into a form accessible to vegetation - ammonium compounds. Nitrogen-fixing nitrifying bacteria can live freely in the soil (azotobacter, clostridium) or be in symbiosis with higher plants (nodule).

The next link in the food chain

For example, when eating plant-based foods, we directly use a product synthesized from the energy of sunlight. With animal food, we get ready-made organic substances that were obtained by animals from plants.

However, heterotrophs cannot completely decompose the received organic food. Waste always remains, which, in turn, is dealt with by a separate group of microorganisms.

Who is involved in the disposal of waste in nature

Bacteria and fungi that use the dead remains of living organisms are called decomposers (from the Latin for "restoration"). They decompose organic residues by oxidation to inorganics and the simplest organic compounds. Reducers differ from other living things in that they do not have solid undigested residues.

In the process of biological treatment, heterotrophic and autotrophic nitrifying bacteria that live in soil, silt, decaying residues, and water bodies are actively involved. They convert ammonia released by other living organisms along with waste products into nitric acid salts (nitrates). The nitrification process takes place in two stages. First, ammonia is oxidized to nitrite, then the next group of bacteria oxidizes nitrite to nitrate.

This group of bacteria returns mineral salts to the soil and water, which are again used by autotrophic producers. In this way, the circulation of mineral components in nature is closed.

Living biological filters

In practice, the properties of nitrifying bacteria are widely used in the design of biological filters for aquariums.

An aquarium with clean walls and clear water, in which colorful fish swim, is a decoration for any room and an object of legitimate pride for the owner. Keeping your aquarium clean is not easy. Remains of food, fish excrement, and particles of dead algae do not make the water cleaner.

For quite a long time, aquarium lovers have used only mechanical cleaning methods. Unlike mechanics, a biological filter is not a device, but a certain set of processes, as a result of which toxic compounds are removed from water:

1. Ammonium contained in urea, which, when the pH of the water rises, turns into the more dangerous ammonia. The relationship between temperature and pH in an aquarium is directly related to the amount of toxic ammonia. At 20 ° C and pH 7, the ammonia content is 0.5%, and at 25 ° C and pH 8.4 - already 10%.
2. The next hazard is nitrite, produced by the oxidation of ammonia.
3. Oxidation of nitrite produces nitrate, which is also toxic.

The first method is laborious (who wants to run with buckets?), And the second requires certain conditions - bacteria need food, a comfortable temperature and a place to live.

There are two groups of bacteria involved in the biological filter for aquariums - nitrifying bacteria (Nitrosomonas) and nitrobacteria (Nitrobacter). Nitrifying bacteria make nitrite from ammonia, and nitrobacteria make nitrate from nitrite. The result of the latter reaction is partly used by algae, but most of the nitrate can only be removed by changing the water in the aquarium. No bacteria can get rid of the need to run around with buckets.

For bacteria to live comfortably in an aquarium, a temperature of 26 -27⁰C, the presence of oxygen (aeration) and photosynthesis (aquatic plants) are required. The inhabitants of the aquarium will provide them with food, and the aquarium soil will serve as their home.

So, microorganisms process inorganic substances in the environment and create conditions in the soil for plant nutrition. Plants, in turn, are the source of energy for animals. At the next stage, predatory animals take energy from their herbivorous counterparts. Man, like all higher predators, can get food from both plants and animals. The remains of the vital activity of animals and plants serve as food for microorganisms that supply inorganic substances. The circle is complete.

Maintaining life and obtaining energy is possible in completely different natural conditions. The possibility of the emergence of a new life in unimaginable, at first glance, conditions proves how multifaceted and so far little studied our habitat.

• Auto Photo trophies - energy for the synthesis of organic substances is obtained from light (photosynthesis). Phototrophs include plants and photosynthetic bacteria.
• Auto chemo trophs - energy for the synthesis of organic substances is obtained by the oxidation of inorganic substances (chemosynthesis). For example,
  • sulfur bacteria oxidize hydrogen sulfide to sulfur,
  • iron bacteria oxidize ferrous iron to ferric,
  • nitrifying bacteria oxidize ammonia to nitric acid.

Similarities and differences between photosynthesis and chemosynthesis

• Similarities: all this is a plastic exchange, organic substances are made from inorganic substances (from carbon dioxide and water - glucose).
• Difference: the energy for synthesis in photosynthesis is taken from light, and in chemosynthesis - from redox reactions.

ATTENTION! The difference between auto- and heterotrophs lies in the method of obtaining organic substances ("get ready-made" or "do it yourself"). Both auto- and heterotrophs obtain energy for vital activity by respiration.

Comparison of respiration and photosynthesis

Tests and assignments

AUTOTROPHES
Choose three options. Autotrophs include
1) spore plants
2) molds
3) unicellular algae
4) chemotrophic bacteria
5) viruses
6) most protozoa

Answer

1. Identify two organisms that "drop out" from the list of autotrophic organisms, and write down the numbers under which they are indicated.
1) Common amoeba
2) Venus flytrap
3) Pinullaria green
4) Infusoria slipper
5) Spirogyra

Answer

2. All the organisms listed below, except for two, are classified as autotrophs by the type of nutrition. Identify two organisms that "drop out" from the general list, and write down the numbers under which they are indicated.
1) chlamydomonas
2) field horsetail
3) boletus
4) cuckoo flax
5) yeast

Answer

3. All the organisms listed below, except for two, are classified as autotrophs by the type of nutrition. Identify two organisms that "drop out" from the general list, and write down the numbers under which they are indicated.
1) sulfur bacteria
2) spirogyra
3) fly agaric
4) sphagnum
5) bacteriophage

Answer

4. All the organisms listed below, except for two, are classified as autotrophs by the type of nutrition. Identify two organisms that "drop out" from the general list, and write down the numbers under which they are indicated.
1) cyanobacteria
2) amoeba
3) kelp
4) sphagnum
5) penicillus

Answer

Answer

Answer

Choose the one that is most correct. What organism is classified as heterotroph by the way of nutrition?
1) chlamydomonas
2) kelp
3) penicillus
4) chlorella

Answer

Choose the one that is most correct. Putrefaction bacteria are by the way organisms feed
1) chemotrophic
2) autotrophic
3) heterotrophic
4) symbiotic

Answer

AUTOTROPHES - HETEROTROPHES
1. Establish a correspondence between the peculiarity of metabolism and the group of organisms for which it is characteristic: 1) autotrophs, 2) heterotrophs
A) the release of oxygen into the atmosphere
B) using the energy contained in food to synthesize ATP
C) use of ready-made organic substances
D) synthesis of organic substances from inorganic
E) using carbon dioxide for food

Answer

2. Establish a correspondence between the characteristics and the way of feeding organisms: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the correct order.
A) carbon dioxide serves as a carbon source
B) accompanied by photolysis of water
C) the energy of oxidation of organic substances is used
D) the energy of oxidation of inorganic substances is used
E) food intake by phagocytosis

Answer

3. Establish a correspondence between the dietary habits of an organism and a group of organisms: 1) autotrophs, 2) heterotrophs. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) capture food by phagocytosis
B) use the energy released during the oxidation of inorganic substances
C) get food by filtering water
D) synthesize organic substances from inorganic
D) use the energy of sunlight
E) use the energy contained in food

Answer

AUTOTROPHES - HETEROTROPHES EXAMPLES
1. Establish a correspondence between the example and the way of feeding: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the correct order.
A) cyanobacteria
B) kelp
C) bovine tapeworm
D) dandelion
E) fox

Answer

2. Establish a correspondence between the organism and the type of nutrition: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) Siberian pine
B) Escherichia coli
C) human amoeba
D) penicill
D) field horsetail
E) chlorella

Answer

3. Establish a correspondence between unicellular organisms and the type of nutrition that is characteristic of it: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) cholera vibrio
B) iron bacteria
C) malaria plasmodium
D) chlamydomonas
E) cyanobacteria
E) dysentery amoeba

Answer

4. Establish a correspondence between examples and methods of nutrition: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) spirogyra
B) bull tapeworm
C) field horsetail
D) sulfur bacteria
E) green grasshopper

Answer

5. Establish a correspondence between examples and methods of nutrition: 1) autotrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) chlorella
B) frog
C) champignon
D) fern
E) kelp

Answer

COLLECT 6:
A) mucor
B) nitrifying bacteria
C) tinder fungus

CHEMOTROPHES
Choose the one that is most correct. What organisms convert the oxidation energy of inorganic substances into high-energy ATP bonds?
1) phototrophs
2) chemotrophs
3) heterotrophs
4) saprotrophs

Answer

Chemosynthetic bacteria are able to obtain energy from the compounds of all but two elements. Identify two items that "drop out" from the general list, and write down the numbers under which they are indicated.
1) Nitrogen
2) Chlorine
3) Iron
4) Magnesium
5) Sulfur

Answer

PHOTOTROPHES - CHEMOTROPHES
Establish a correspondence between the characteristics of organisms and the way they are fed: 1) phototrophic, 2) chemotrophic. Write down the numbers 1 and 2 in the correct order.
A) light energy is used
B) oxidation of inorganic substances occurs
C) the reactions take place in the thylakoids
D) accompanied by the release of oxygen
E) inherent in hydrogen and nitrifying bacteria
E) requires chlorophyll

Answer

Choose the one that is most correct. The similarity between chemosynthesis and photosynthesis is that in both processes
1) solar energy is used to form organic matter
2) the formation of organic substances uses the energy released during the oxidation of inorganic substances
3) carbon dioxide is used as a carbon source
4) the final product is released into the atmosphere - oxygen

Answer

PHOTOTROPHES - CHEMOTROPHES EXAMPLES
1. Establish a correspondence between a group of organisms and the process of transformation of substances, which is characteristic of it: 1) photosynthesis, 2) chemosynthesis
A) ferns
B) iron bacteria
C) brown algae
D) cyanobacteria
E) green algae
E) nitrifying bacteria

Answer

2. Establish a correspondence between examples and methods of feeding living organisms: 1) phototrophic, 2) chemotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) spirogyra
B) nitrifying bacteria
C) chlorella
D) sulfur bacteria
E) iron bacteria
E) chlorococcus

Answer

PHOTOTROPHES - CHEMOTROPHES - HETEROTROPHES
1. Establish a correspondence between the organism and the way of its nutrition: 1) phototrophic, 2) heterotrophic, 3) chemotrophic. Write down the numbers 1, 2 and 3 in the correct order.
A) spirogyra
B) penicill
C) sulfur bacteria
D) cyanobacteria
D) earthworm

Answer

2. Establish a correspondence between organisms and the types of their nutrition: 1) phototrophic, 2) heterotrophic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) lamblia
B) ergot mushroom
C) chlamydomonas
D) cyanobacteria
D) sphagnum

Answer

PHOTOSYNTHESIS - BREATHING
1. Establish a correspondence between characteristic and process: 1) photosynthesis, 2) glycolysis. Write down the numbers 1 and 2 in the correct order.
A) occurs in chloroplasts
B) glucose is synthesized
B) is a stage of energy metabolism
D) occurs in the cytoplasm
E) photolysis of water occurs

Answer

2. Establish a correspondence between the characteristic and the life process of the plant to which it belongs: 1-photosynthesis, 2-respiration
1) glucose is synthesized
2) organic matter is oxidized
3) oxygen is released
4) carbon dioxide is formed
5) occurs in mitochondria
6) is accompanied by energy absorption

Answer

3. Establish a correspondence between the process and the type of metabolism in the cell: 1) photosynthesis, 2) energy metabolism
A) the formation of pyruvic acid (PVA)
B) occurs in the mitochondria
C) photolysis of water molecules
D) synthesis of ATP molecules due to light energy
D) occurs in chloroplasts
E) the synthesis of 38 ATP molecules during the splitting of the glucose molecule

Answer

4. Establish a correspondence between the sign of plant life and the process of respiration or photosynthesis: 1) respiration, 2) photosynthesis
A) is carried out in cells with chloroplasts
B) occurs in all cells
B) oxygen is absorbed
D) carbon dioxide is absorbed
E) organic substances are formed from inorganic substances in the light
E) organic matter is oxidized

Answer

5. Establish the correspondence between the features and between the processes: 1) photosynthesis, 2) respiration. Write down the numbers 1 and 2 in the correct order.
A) ATP is formed in chloroplasts
B) occurs in all living cells
C) ATP is formed in mitochondria
D) end products - organic matter and oxygen
E) initial substances - carbon dioxide and water
E) energy is released

Answer

6. Establish a correspondence between the processes and their characteristics: 1) respiration, 2) photosynthesis. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) oxygen is absorbed and carbon dioxide and water are released
B) organic matter is formed
C) occurs in chloroplasts in the light
D) carbon dioxide and water are absorbed and oxygen is released
D) occurs in mitochondria in the light and in the dark
E) organic matter is broken down

Answer

Establish a correspondence between the process taking place in the cell and the organoid in which it occurs: 1) mitochondria, 2) chloroplast. Write down the numbers 1 and 2 in the correct order.
A) reduction of carbon dioxide to glucose
B) synthesis of ATP during respiration
C) primary synthesis of organic substances
D) conversion of light energy into chemical
E) splitting organic matter to carbon dioxide and water

Answer

Establish a correspondence between the signs of an organoid and an organoid, for which these signs are characteristic: 1) Chloroplast, 2) Mitochondria. Write down the numbers 1 and 2 in the correct order.
A) Contains green pigment
B) Consists of a double membrane, thylakoids and gran
C) Converts light energy into chemical energy
D) Consists of a double membrane and cristae
E) Provides the final oxidation of nutrients
E) Stores energy in the form of 38 mol of ATP when 1 mol of glucose is broken down

Answer

BREATHING OF PLANTS
Choose the one that is most correct. In the process of respiration, the plants are provided
1) energy
2) water
3) organic substances
4) minerals

Answer

Choose the one that is most correct. Cultivated plants do not grow well in swampy soil, since in it
1) insufficient oxygen content
2) methane is formed
3) excess organic matter
4) contains a lot of peat

Answer

Choose the one that is most correct. Plants in the process of breathing use oxygen, which enters the cells and provides
1) oxidation of inorganic substances to carbon dioxide and water
2) oxidation of organic substances with the release of energy
3) synthesis of organic substances from inorganic
4) protein synthesis from amino acids

Answer

Choose the one that is most correct. Plants in the process of breathing
1) release oxygen and absorb carbon dioxide
2) absorb oxygen and emit carbon dioxide
3) accumulate energy in the resulting organic matter
4) synthesize organic substances from inorganic

Answer

Choose the one that is most correct. To ensure the access of air oxygen to the roots of plants, the soil must
1) fertilize with potassium salts
2) loosen before watering and during watering
3) fertilize with nitrogen salts
4) loosen after watering

Answer

Analyze the text "Plant Breathing". For each letter cell, select the appropriate term from the list provided. The process of plant respiration is constant. During this process, the plant organism consumes ________ (A), and secretes ________ (B). Waste gases are removed from the plant by diffusion. In the sheet, they are removed through special formations - ________ (B), located in the skin. When breathing, the energy of organic substances is released, stored during the ________ (D), which occurs in the green parts of the plant in the light.
1) water
2) evaporation
3) oxygen
4) transpiration
5) carbon dioxide
6) stomata
7) photosynthesis
8) lentils

Answer

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