Correct sequence of photosynthesis processes. How and where does photosynthesis take place in plants? It takes place in two phases.

14.05.2020

All living organisms that live on Earth are open systems that depend on the supply of matter and energy from outside. The process of consuming matter and energy is called food . Chemical substances necessary for building the body, energy - for the implementation of vital processes. There are two types of nutrition of living organisms: autotrophic and heterotrophic, and three groups of organisms according to the type of nutrition: autotrophs, heterotrophs and mixotrophs.

Classification of living organisms by types of nutrition

A type	Characteristic	organisms
Autotrophs	Organisms that use carbon dioxide as a source of carbon. In other words, these are organisms capable of creating organic substances from inorganic - carbon dioxide, water, mineral salts	Plants and some bacteria
Heterotrophs	Organisms that use carbon as a source organic compounds	Animals, fungi and most bacteria
Mixotrophs	Organisms with a mixed type of nutrition, which, depending on habitat conditions, can both synthesize organic substances from inorganic substances and feed on ready-made organic compounds.	Insectivorous plants, representatives of the Euglena algae department, etc.

Depending on the source of energy, autotrophs are divided into photoautotrophs and chemoautotrophs.

Classification of autotrophs depending on the energy source

According to the method of obtaining food, heterotrophs are divided into phagotrophs (holozoans) and osmotrophs.

Classification of heterotrophs according to the method of obtaining food

According to the state of the food source, heterotrophs are divided into biotrophs and saprotrophs.

Metabolism- the totality of all chemical reactions occurring in a living organism. The value of metabolism is to create the substances necessary for the body and provide it with energy.

Components of metabolism

The processes of plastic and energy exchange are inextricably linked. All synthetic (anabolic) processes require energy supplied during dissimilation reactions. The reactions of splitting (catabolism) themselves proceed only with the participation of enzymes synthesized in the process of assimilation.

The role of ATP in metabolism

Energy released during decay organic matter, is not immediately used by the cell, but is stored in the form of high-energy compounds, usually in the form of adenosine triphosphate (ATP). In its own way chemical nature ATP is a mononucleotide.

ATP (adenosine triphosphate)- a mononucleotide consisting of adenine, ribose and three phosphoric acid residues, interconnected by macroergic bonds.

These bonds store energy, which is released when they are broken:
ATP + H 2 O → ADP + H 3 PO 4 + Q 1
ADP + H 2 O → AMP + H 3 PO 4 + Q 2
AMP + H 2 O → adenine + ribose + H 3 PO 4 + Q 3,
where ATP is adenosine triphosphoric acid; ADP - adenosine diphosphoric acid; AMP - adenosine monophosphoric acid; Q 1 \u003d Q 2 \u003d 30.6 kJ; Q 3 \u003d 13.8 kJ.
The supply of ATP in the cell is limited and replenished through the process of phosphorylation. Phosphorylation- addition of a phosphoric acid residue to ADP (ADP + F → ATP). It occurs with varying intensity during respiration, fermentation, and photosynthesis. ATP is renewed extremely quickly (in humans, the lifespan of one ATP molecule is less than 1 minute).
The energy stored in ATP molecules is used by the body in anabolic reactions (biosynthesis reactions). The ATP molecule is the universal store and carrier of energy for all living beings.

energy exchange

The energy necessary for life, most organisms receive as a result of the oxidation of organic substances, that is, as a result of catabolic reactions. The most important compound acting as a fuel is glucose.
In relation to free oxygen, organisms are divided into three groups.

Classification of organisms in relation to free oxygen

In obligate aerobes and facultative anaerobes, in the presence of oxygen, catabolism proceeds in three stages: preparatory, oxygen-free, and oxygen. As a result, organic substances break down into inorganic compounds. At obligate anaerobes and facultative anaerobes with a lack of oxygen, catabolism proceeds in the first two stages: preparatory and anoxic. As a result, intermediate organic compounds are formed, which are still rich in energy.

Stages of catabolism

1. The first stage is preparatory- consists in the enzymatic splitting of complex organic compounds into simpler ones. Proteins are broken down into amino acids, fats into glycerol and fatty acids, polysaccharides into monosaccharides, nucleic acids into nucleotides. In multicellular organisms, this occurs in the gastrointestinal tract, in unicellular organisms, in lysosomes under the action of hydrolytic enzymes. The released energy is dissipated in the form of heat. The resulting organic compounds either undergo further oxidation or are used by the cell to synthesize its own organic compounds.
2. The second stage - incomplete oxidation (oxygen-free)- consists in the further splitting of organic substances, is carried out in the cytoplasm of the cell without the participation of oxygen. The main source of energy in the cell is glucose. Anoxic, incomplete oxidation of glucose is called glycolysis. As a result of glycolysis of one glucose molecule, two molecules of pyruvic acid (PVK, pyruvate) CH 3 COCOOH, ATP and water are formed, as well as hydrogen atoms, which are bound by the NAD + carrier molecule and stored in the form of NAD H.
The overall formula for glycolysis is as follows:
C 6 H 12 O 6 + 2H 3 PO 4 + 2ADP + 2NAD + → 2C 3 H 4 O 3 + 2H 2 O + 2ATP + 2NAD H.
Further in the absence of oxygen in the environment glycolysis products (PVK and NAD H) are processed either into ethyl alcohol - alcoholic fermentation(in yeast and plant cells with a lack of oxygen)
CH 3 COCOOH → CO 2 + CH 3 SON
CH 3 SON + 2NAD H → C 2 H 5 OH + 2NAD +,
or into lactic acid - lactic acid fermentation (in animal cells with a lack of oxygen)
CH 3 COCOOH + 2NAD H → C 3 H 6 O 3 + 2NAD +.
In the presence of oxygen in the environment glycolysis products undergo further cleavage to final products.
3. The third stage - complete oxidation (respiration)- consists in the oxidation of PVC to carbon dioxide and water, is carried out in mitochondria with the obligatory participation of oxygen.
It consists of three stages:
A) the formation of acetylcoenzyme A;
B) oxidation of acetyl coenzyme A in the Krebs cycle;
C) oxidative phosphorylation in the electron transport chain.

A. At the first stage, PVA is transferred from the cytoplasm to the mitochondria, where it interacts with matrix enzymes and forms 1) carbon dioxide, which is excreted from the cell; 2) hydrogen atoms, which are delivered by carrier molecules to the inner membrane of the mitochondria; 3) acetyl coenzyme A (acetyl-CoA).
B. At the second stage, acetylcoenzyme A is oxidized in the Krebs cycle. The Krebs cycle (tricarboxylic acid cycle, citric acid cycle) is a chain of successive reactions during which 1) two molecules of carbon dioxide, 2) an ATP molecule and 3) four pairs of hydrogen atoms are formed from one molecule of acetyl-CoA, and 3) four pairs of hydrogen atoms are transferred to molecules - carriers - OVER and FAD. Thus, as a result of glycolysis and the Krebs cycle, the glucose molecule is broken down to CO 2, and the energy released in this case is spent on the synthesis of 4 ATP and accumulates in 10 NAD H and 4 FAD H 2.
C. In the third stage, hydrogen atoms with NADH and FAD H 2 are oxidized by molecular oxygen O 2 to form water. One NAD H is able to form 3 ATP, and one FAD H 2 -2 ATP. Thus, the energy released in this case is stored in the form of another 34 ATP.
This process proceeds as follows. Hydrogen atoms are concentrated near the outer side of the inner mitochondrial membrane. They lose electrons, which are transferred along the chain of carrier molecules (cytochromes) of the electron transport chain (ETC) to the inner side of the inner membrane, where they combine with oxygen molecules:
O 2 + e - → O 2 -.
As a result of the activity of the enzymes of the electron transport chain, the inner membrane of mitochondria is negatively charged from the inside (due to O 2 -), and from the outside it is positively charged (due to H +), so that a potential difference is created between its surfaces. Molecules of the enzyme ATP synthetase with an ion channel are built into the inner membrane of mitochondria. When the potential difference across the membrane reaches a critical level, the positively charged particles H + force electric field begin to push through the ATPase channel and, once on the inner surface of the membrane, interact with oxygen, forming water:
1/2O 2 - + 2H + → H 2 O.
The energy of hydrogen ions H + transported through the ion channel of the inner membrane of the mitochondria is used to phosphorylate ADP to ATP:
ADP + F → ATP.
This formation of ATP in mitochondria with the participation of oxygen is called oxidative phosphorylation.
The overall equation for the breakdown of glucose in the process of cellular respiration:
C 6 H 12 O 6 + 6O 2 + 38H 3 PO 4 + 38ADP → 6CO 2 + 44H 2 O + 38ATP.
Thus, during glycolysis, 2 ATP molecules are formed, during cellular respiration - another 36 ATP molecules, in general, with complete oxidation of glucose - 38 ATP molecules.

plastic exchange

Plastic exchange, or assimilation, is a set of reactions that ensure the synthesis of complex organic compounds from simpler ones (photosynthesis, chemosynthesis, protein biosynthesis, etc.).
Heterotrophic organisms build their own organic matter from organic food components. Heterotrophic assimilation essentially boils down to rearrangement of molecules:
food organic substances (proteins, fats, carbohydrates) → simple organic molecules (amino acids, fatty acids, monosaccharides) → body macromolecules (proteins, fats, carbohydrates).
Autotrophic organisms are capable of completely independently synthesizing organic substances from inorganic molecules consumed from the external environment. In the process of photo- and chemosynthesis, the formation of simple organic compounds occurs, from which macromolecules are subsequently synthesized:
inorganic substances (CO 2, H 2 O) → simple organic molecules (amino acids, fatty acids, monosaccharides) → macromolecules of the body (proteins, fats, carbohydrates).

Photosynthesis

Photosynthesis- synthesis of organic compounds from inorganic ones due to the energy of light.

The overall photosynthesis equation is:

Photosynthesis takes place with the participation photosynthetic pigments, which have the unique property of converting the energy of sunlight into the energy of a chemical bond in the form of ATP. Photosynthetic pigments are protein-like substances. The most important pigment is chlorophyll. In eukaryotes, photosynthetic pigments are embedded in the inner membrane of plastids, in prokaryotes, in invaginations of the cytoplasmic membrane.
The structure of the chloroplast is very similar to that of the mitochondria. The inner membrane of thylakoid gran contains photosynthetic pigments, as well as proteins of the electron transport chain and molecules of the enzyme ATP synthetase.
The process of photosynthesis consists of two phases: light and dark.
1. Light phase of photosynthesis proceeds only in the light in the membrane of the thylakoids of the grana.
It includes the absorption of light quanta by chlorophyll, the formation of an ATP molecule, and the photolysis of water.
Under the action of a light quantum (hv), chlorophyll loses electrons, passing into an excited state:

These electrons are transferred by carriers to the outer, that is, the surface of the thylakoid membrane facing the matrix, where they accumulate.
At the same time, photolysis of water occurs inside the thylakoids, that is, its decomposition under the action of light:

The resulting electrons are transferred by carriers to chlorophyll molecules and restore them. The chlorophyll molecules return to a stable state.
Hydrogen protons, formed during the photolysis of water, accumulate inside the thylakoid, creating an H + -reservoir. As a result, the inner surface of the thylakoid membrane is charged positively (due to H +), and the outer surface is negatively charged (due to e -). As oppositely charged particles accumulate on both sides of the membrane, the potential difference increases. When the critical value of the potential difference is reached, the strength of the electric field begins to push protons through the ATP synthetase channel. The energy released in this case is used to phosphorylate ADP molecules:
ADP + F → ATP.

The formation of ATP during photosynthesis under the influence of light energy is called photophosphorylation.
Hydrogen ions, once on the outer surface of the thylakoid membrane, meet electrons there and form atomic hydrogen, which binds to the hydrogen carrier molecule NADP (nicotinamide adenine dinucleotide phosphate):
2H + + 4e - + NADP + → NADP H 2.
Thus, during the light phase of photosynthesis, three processes occur: the formation of oxygen due to the decomposition of water, the synthesis of ATP, and the formation of hydrogen atoms in the form of NADP·H 2 . Oxygen diffuses into the atmosphere, while ATP and NADP H 2 participate in the processes of the dark phase.
2. Dark phase of photosynthesis proceeds in the chloroplast matrix both in the light and in the dark and is a series of successive transformations of CO 2 coming from the air in the Calvin cycle. The reactions of the dark phase are carried out due to the energy of ATP. In the Calvin cycle, CO 2 binds to hydrogen from NADP·H 2 to form glucose.
In the process of photosynthesis, in addition to monosaccharides (glucose, etc.), monomers of other organic compounds are synthesized - amino acids, glycerol and fatty acids. Thus, thanks to photosynthesis, plants provide themselves and all life on Earth with the necessary organic substances and oxygen.

Comparative characteristics of photosynthesis and respiration of eukaryotes

sign	Photosynthesis	Breath
Reaction equation	6CO 2 + 6H 2 O + light energy → C 6 H 12 O 6 + 6O 2	C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy (ATP)
starting materials	carbon dioxide, water
reaction products	organic matter, oxygen	carbon dioxide, water
Significance in the cycle of substances	Synthesis of organic substances from inorganic	Decomposition of organic substances to inorganic
Energy transformation	Converting light energy into energy chemical bonds organic matter	The conversion of the energy of chemical bonds of organic substances into the energy of macroergic bonds of ATP
Milestones	Light and dark phase (including the Calvin cycle)	Incomplete oxidation (glycolysis) and complete oxidation (including the Krebs cycle)
Place of the process	Chloroplasts	Hyaloplasm (incomplete oxidation) and mitochondria (complete oxidation)

Genetic information in all organisms is stored in the form of a specific sequence of DNA nucleotides (or RNA for RNA-containing viruses). Prokaryotes contain genetic information in the form of a single DNA molecule. In eukaryotic cells, the genetic material is distributed in several DNA molecules organized into chromosomes.
DNA consists of coding and non-coding regions. Coding regions code for RNA. Non-coding regions of DNA perform structural function, allowing regions of genetic material to be packaged in a particular way, or regulatory function, participating in the inclusion of genes that direct protein synthesis.
Genes are the coding regions of DNA. Gene - a section of a DNA molecule encoding the synthesis of one mRNA (and, accordingly, a polypeptide), rRNA or tRNA.
The region of the chromosome where the gene is located is called locus . The set of genes in the cell nucleus is genotype , the totality of genes of the haploid set of chromosomes - genome , a set of extranuclear DNA genes (mitochondria, plastids, cytoplasm) - plasmon .
The implementation of the information recorded in the genes through the synthesis of proteins is called expression (manifestation) of genes. Genetic information is stored in the form of a certain sequence of DNA nucleotides, and is realized in the form of a sequence of amino acids in a protein. RNA mediates and carries information. That is, the implementation of genetic information occurs as follows:
DNA → RNA → protein.
This process is carried out in two stages:
1) transcription;
2) broadcast.

Transcription(from lat. transcription- rewriting) - the synthesis of RNA using DNA as a template. As a result, mRNA, tRNA and rRNA are formed. The transcription process requires a large expenditure of energy in the form of ATP and is carried out by the enzyme RNA polymerase.

At the same time, not the entire DNA molecule is transcribed, but only its individual segments. Such a segment ( transcripton) starts promoter- a section of DNA where RNA polymerase attaches and where transcription begins and ends terminator a segment of DNA containing a signal for the end of transcription. A transcripton is a gene in terms of molecular biology.
Transcription, like replication, is based on the ability of the nitrogenous bases of nucleotides to complementary binding. At the time of transcription, the DNA double strand is broken, and RNA synthesis is carried out along one DNA strand.

During transcription, the DNA nucleotide sequence is transcribed onto the synthesized mRNA molecule, which acts as a template in the process of protein biosynthesis.
The genes of prokaryotes consist only of coding nucleotide sequences.

Eukaryotic genes consist of alternating coding ( exons) and non-coding ( introns) plots.

After transcription, mRNA regions corresponding to introns are removed during splicing, which is an integral part of processing.

Processing- the process of formation of mature mRNA from its precursor pre-mRNA. It includes two main events. 1. Attachment to the ends of mRNA short sequences of nucleotides, indicating the start and end of translation. 2. Splicing- removal of non-informative mRNA sequences corresponding to DNA introns. As a result of splicing molecular mass mRNA is reduced by 10 times.
Broadcast(from lat. translation- translation) - the synthesis of a polypeptide chain using mRNA as a template.

All three types of RNA are involved in translation: mRNA is the information matrix; tRNAs deliver amino acids and recognize codons; rRNA together with proteins form ribosomes that hold mRNA, tRNA and protein and carry out the synthesis of the polypeptide chain.

Broadcast stages

Stage	Characteristic
Initiation	Assembly of the complex involved in the synthesis of the polypeptide chain. A small subunit of the ribosome binds to the initiator met-t rna, and then with m pH to, after which the formation of a whole ribosome, consisting of small and large subparticles, occurs.
Elongation	elongation of the polypeptide chain. The ribosome moves along rna, which is accompanied by repeated repetition of the cycle of addition of the next amino acid to the growing polypeptide chain.
Termination	Completion of the synthesis of the polypeptide molecule. The ribosome reaches one of three stop codons rna, and since there is no t rna with anticodons complementary to stop codons, the synthesis of the polypeptide chain stops. It is released and separated from the ribosome. Ribosomal subunits dissociate, separate from mRNA, and can take part in the synthesis of the next polypeptide chain.

Matrix synthesis reactions

self-duplication of DNA (replication);
the formation of mRNA, tRNA and rRNA on a DNA molecule (transcription);
protein biosynthesis to mRNA (translation).

All these reactions are united by the fact that a DNA molecule in one case or an mRNA molecule in another act as a template on which identical molecules are formed. Matrix synthesis reactions are the basis of the ability of living organisms to reproduce their own kind.
Regulation of gene expression. The body of a multicellular organism is built from a variety of cell types. They differ in structure and function, that is, they are differentiated. The differences are manifested in the fact that in addition to the proteins necessary for any cell of the body, cells of each type also synthesize specialized proteins: keratin is formed in the epidermis, hemoglobin is formed in erythrocytes, etc. Cell differentiation is due to a change in the set of expressed genes and is not accompanied by any irreversible changes in the structure of the DNA sequences themselves.

cell division

Chromosomal set

Chromosomal set - a set of chromosomes contained in the nucleus. Depending on the chromosome set, cells are somatic and sexual.

Somatic and germ cells

cell cycle

cell cycle (cell life cycle) - the existence of a cell from the moment it arises as a result of the division of the mother cell to its own division or death. The duration of the cell cycle depends on the type of cell, its functional state and environmental conditions. The cell cycle includes a mitotic cycle and a dormant period.

V rest period (G 0) the cell performs its inherent functions and chooses a further fate - it dies or returns to the mitotic cycle. In continuously reproducing cells, the cell cycle coincides with the mitotic cycle, and there is no rest period.
Mitotic cycle consists of four periods: presynthetic (postmitotic) - G 1, synthetic - S, postsynthetic (premitotic) - G 2, mitosis - M. The first three periods are the preparation of the cell for division ( interphase), the fourth period is the division itself (mitosis).

Interphase - preparation of the cell for division.

Interphase periods

division of eukaryotic cells

basis for reproduction and individual development organisms is cell division.
Eukaryotic cells have three ways of dividing:

amitosis (direct division),
mitosis (indirect division),
meiosis (reduction division).

Amitosis- a rare way of cell division, characteristic of aging or tumor cells. During amitosis, the nucleus is divided by constriction and the uniform distribution of hereditary material is not ensured. After amitosis, the cell is not able to enter into mitotic division.

Mitosis- a type of cell division, as a result of which daughter cells receive genetic material identical to that contained in the mother cell. As a result of mitosis, two diploid cells, genetically identical to the parent, are formed from one diploid cell.

Phases of mitosis

Phases	Number of chromosomes and chromatids	Processes
Prophase	2n4c	Chromosomes spiralize, centrioles (in animal cells) diverge to the poles of the cell, the nuclear membrane disintegrates, the nucleoli disappear, and the division spindle begins to form.
metaphase	2n4c	Chromosomes, consisting of two chromatids, are attached by their own centromeres(primary constrictions) to the fission spindle threads. Moreover, all of them are located in the equatorial plane. This structure is called metaphase plate.
Anaphase	2n2c	The centromeres divide, and the spindle fibers stretch the separated chromatids to opposite poles. The separated chromatids are now called daughter chromosomes.
Telophase	2n2c	Daughter chromosomes reach the poles of the cell, despiralize, the spindle fibers are destroyed, a nuclear envelope is formed around the chromosomes, and the nucleoli are restored. The two nuclei formed are genetically identical. After that follows cytokinesis(division of the cytoplasm), which results in the formation of two daughter cells. Organelles are distributed between them more or less evenly.

The biological significance of mitosis:

genetic stability is achieved;
the number of cells in the body increases;
body grows;
phenomena of regeneration and asexual reproduction are possible in some organisms.

Meiosis

Meiosis- a type of cell division, accompanied by a reduction in the number of chromosomes. As a result of meiosis, four haploid cells are formed from one diploid cell, genetically different from the mother. During meiosis, two cell divisions occur (the first and second meiotic divisions), and the doubling of the number of chromosomes occurs only before the first division.

Phases of meiosis

Phases	Number of chromosomes and chromatids	Processes
Prophase I	2n4c	There are processes similar to the processes of prophase of mitosis. In addition, homologous chromosomes, represented by two chromatids, approach and "stick" to each other. This process is called conjugation. In this case, there is an exchange of sections of homologous chromosomes - crossing over(cross chromosomes), that is, the exchange of hereditary information. After conjugation, homologous chromosomes separate from each other.
Metaphase I	2n4c	There are processes similar to those of the metaphase of mitosis.
Anaphase I	1n2c	Unlike the anaphase of mitosis, the centromeres do not divide, and not one chromatid from each chromosome departs to the poles of the cell, but one chromosome, consisting of two chromatids and held together by a common centromere.
Telophase I	1n2c	Two cells with a haploid set are formed.
Interphase	1n2c	Short. Replication (doubling) of DNA does not occur and, therefore, diploidy is not restored.
Prophase II	1n2c
Metaphase II	1n2c	Similar to the processes during mitosis.
Anaphase II	1n1c	Similar to the processes during mitosis.
Telophase II	1n1c	Similar to the processes during mitosis.

The biological significance of meiosis:

the basis of sexual reproduction;
basis of combinative variability.

division of prokaryotic cells

Prokaryotes do not have mitosis or meiosis. Bacteria reproduce asexually - cell division with the help of constrictions or partitions, less often budding. These processes are preceded by the duplication of the circular DNA molecule.
In addition, bacteria are characterized by a sexual process - conjugation. When conjugated through a special channel formed between two cells, a DNA fragment of one cell is transferred to another cell, that is, the hereditary information contained in the DNA of both cells changes. Since the number of bacteria does not increase, for correctness, the concept of "sexual process" is used, but not "sexual reproduction".

A)
splitting of biopolymers to monomers B)
breakdown of glucose molecules to pyruvic acid

B) oxidation
pyruvic acid to carbon dioxide and water

D) storage
energy in ATP molecules

D) synthesis
amino acid protein molecules

E)
use of atmospheric oxygen

Install the correct
sequence of photosynthesis processes.

A)
converting solar energy into atf energy

B)
formation of excited chlorophyll electrons

B) fixation
carbon dioxide

G)
starch formation

D)
conversion of ATP energy into energy
glucose

1. Carbohydrates during photosynthesis are synthesized from:

1)02iH2O 3)C02iH20

2) CO2 and H2 4) CO2 and H2CO3

2. The consumer of carbon dioxide in the biosphere is:

1) oak 3) earthworm

2) eagle 4) soil bacterium

3. In which case is the glucose formula correctly written:

1) CH10 O5 3) CH12 About

2) C5H220 4) C3H603

4. The source of energy for the synthesis of ATP in chloroplasts is:

1) carbon dioxide and water 3) NADP H2

2) amino acids 4) glucose

5. In the process of photosynthesis in plants, carbon dioxide is reduced to:

1) glycogen 3) lactose

2) cellulose 4) glucose

6. Organic substances from inorganic can create:

1) Escherichia coli 3) pale grebe

2) chicken 4) cornflower

7. In the light stage of photosynthesis, molecules are excited by light quanta:

1) chlorophyll 3) ATP

2) glucose 4) water

8. Autotrophs do not include:

1) chlorella and spirogyra

2) birch and pine

3) champignon and pale grebe 4) blue-green algae

9.. The main supplier of oxygen to the Earth's atmosphere are:

1) plants 2) bacteria

3) animals 4) people

10. The following have the ability to photosynthesis:

1) protozoa 2) viruses

3) plants 4) mushrooms

11. Chemosynthetics include:

1) iron bacteria 2) influenza and measles viruses

3) cholera vibrios 4) brown algae

12. The plant absorbs when breathing:

1) carbon dioxide and release oxygen

2) oxygen and release carbon dioxide

3)light energy and releases carbon dioxide

4) light energy and release oxygen

13. Photolysis of water occurs during photosynthesis:

1) during the whole process of photosynthesis

2) in the dark phase

3) in the light phase

4) there is no synthesis of carbohydrates

14. The light phase of photosynthesis occurs:

1) on the inner membrane of chloroplasts

2) on the outer membrane of chloroplasts

3) in the stroma of chloroplasts

4) in the mitochondrial matrix

15. In the dark phase of photosynthesis, the following occurs:

1) release of oxygen

2) ATP synthesis

3) synthesis of carbohydrates from carbon dioxide and water

4) excitation of chlorophyll by a photon of light

16. According to the type of nutrition, most plants belong to:

17. In plant cells, unlike human, animal, fungal cells,

1) metabolism 2) aerobic respiration

3) glucose synthesis 4) protein synthesis

18. The source of hydrogen for the reduction of carbon dioxide in the process of photosynthesis is

1) water 2) glucose

3) starch 4) mineral salts

19. In chloroplasts occurs:

1) mRNA transcription 2) formation of ribosomes

3) formation of lysosomes 4) photosynthesis

20. Synthesis of ATP in the cell occurs in the process:

1) glycolysis; 2) photosynthesis;

3) cellular respiration; 4) all listed

Set the correct sequence of processes occurring during mitotic cell division. 1) spiralization of chromosomes 2) formation of nuclear

membranes daughter cells 3) arrangement of chromosomes in the plane of the equator 4) divergence of sister chromatids to the poles of the cell

Establish the sequence of development of symptoms of lung disease in a smoker. 2 Set the sequence of the production steps

conditioned salivary reflex to light.

light bulb ignition

Salivation in response to a light stimulus

Feeding while lighting a light bulb

Formation of a temporary connection

Salivation in response to food

Set the correct sequence of the main stages of photosynthesis.

4
A)

reduction of carbon dioxide to glucose

transport of electrons by carriers and the formation of ATP and NADP

Level B tasks Select three correct answers from the six offered. IN 1. The optical system of the eye includes the cornea 4) pupil lens 5)

vitreous body retina 6) yellow spot B2. In the cavity of the middle ear are the bones of the hammer 4) stirrup horseshoe 5) frenulum anvil 6) cochlea B3. The sense of touch gives information about such properties of an object as size 4) taste color 5) smell shape 6) temperature Establish a correspondence between the contents of the first and second columns. AT 4. Establish a correspondence between the analyzers and their jets. STRUCTURES ANALYZERS A) vitreous body 1) visual B) cochlea 2) spatial (vestibular) C) cones 3) auditory D) rods E) anvil F) semicircular canals A B C D E F C5. Establish a correspondence between the parts of the eye and the structures that make them up.PARTS OF THE EYE STRUCTURES A) eyelids 1) auxiliary apparatus of the eye B) pupil 2) eyeball C) lacrimal glands D) vitreous body E) cornea F) eyelashes A B C D D E C6. Establish a correspondence between the analyzer and the lobe of the cerebral cortex, in which the analysis of these sensations is carried out. tactile) A B C D E Establish the correct sequence of biological processes, phenomena, practical actions. th nerve E) lens B) vitreous body G) visual cortex C) cornea of the cerebral hemispheres D) rods and cones E) lens C8. Establish the sequence of passage of sound and nerve impulse. A) tympanic membrane B) auditory nerve C) malleus D) membrane of the oval window E) anvil E) external auditory canal G) Auricle H) cochlea I) temporal lobe of CBP D) stirrup

Photosynthesis is biosynthesis, consisting in the conversion of light energy into organic compounds. Light in the form of photons is captured by a colored pigment associated with an inorganic or organic electron donor, and allows the mineral material to be used for the synthesis (production) of organic compounds.

In contact with

In other words, what is photosynthesis - this is the process of synthesizing organic matter (sugar) from sunlight. This reaction occurs at the level of chloroplasts, which are specialized cellular organelles that allow carbon dioxide and water to be consumed to produce dioxygen and organic molecules such as glucose.

It takes place in two phases:

Light phase (photophosphorylation) - is a set of light-dependent photochemical (i.e., light-capturing) reactions in which electrons are transported through both photosystems (PSI and PSII) to produce ATP (energy-rich molecule) and NADPHH (reducing potential).

Thus, the light phase of photosynthesis allows the direct conversion of light energy into chemical energy. It is through this process that our planet now has an oxygen-rich atmosphere. As a result, higher plants have managed to dominate the surface of the Earth, providing food for many other organisms that feed or find shelter through it. The original atmosphere contained gases such as ammonium, nitrogen, and carbon dioxide, but very little oxygen. Plants have found a way to turn this CO2 so plentifully into food using sunlight.

The dark phase corresponds to the fully enzymatic and light-independent Calvin cycle, in which adenosine triphosphate (ATP) and NADPH+H+ (nicotine amide adenine dinucleotide phosphate) are used to convert carbon dioxide and water into carbohydrates. This second phase allows the absorption of carbon dioxide.

That is, in this phase of photosynthesis, approximately fifteen seconds after the absorption of CO, a synthesis reaction occurs and the first products of photosynthesis appear - sugars: trioses, pentoses, hexoses, heptoses. Sucrose and starch are formed from certain hexoses. In addition to carbohydrates, they can also develop into lipids and proteins by binding to a nitrogen molecule.

This cycle exists in algae, temperate plants and all trees; these plants are called "C3 plants", the most important intermediate bodies of the biochemical cycle, having a molecule of three carbon atoms (C3).

In this phase, chlorophyll, after absorbing a photon, has an energy of 41 kcal per mole, some of which is converted to heat or fluorescence. The use of isotopic markers (18O) showed that the oxygen released during this process comes from decomposed water and not from absorbed carbon dioxide.

Photosynthesis occurs mainly in plant leaves and rarely (ever) in stems, etc. Parts of a typical leaf include: upper and lower epidermis;

mesophyll;
vascular bundle (veins);
stomata.

If the cells of the upper and lower epidermis are not chloroplasts, photosynthesis does not occur. In fact, they serve primarily as protection for the rest of the leaf.

Stomata are holes found mainly in the lower epidermis and allow air (CO and O2) exchange. The vascular bundles (or veins) in the leaf form part of the plant's transport system, moving water and nutrients around the plant as needed. Mesophyll cells have chloroplasts, this is the site of photosynthesis.

The mechanism of photosynthesis is very complex.. However, these processes in biology are of particular importance. Under vigorous exposure to light, chloroplasts (the parts of a plant cell containing chlorophyll), entering into a photosynthesis reaction, combine carbon dioxide (CO) with fresh water with the formation of sugars C6H12O6.

They are converted into starch C6H12O5 during the reaction, for a square decimeter of leaf surface, an average of 0.2 g of starch per day. The whole operation is accompanied by a strong release of oxygen.

In fact, the process of photosynthesis consists mainly of the photolysis of a water molecule.

The formula for this process is:

6 H 2 O + 6 CO 2 + light \u003d 6 O 2 + C 6 H 12 O 6

Water + carbon dioxide + light = oxygen + glucose

H 2 O = water
CO 2 = carbon dioxide
O 2 = Oxygen
C 6 H 12 O 6 \u003d glucose

In translation, this process means: a plant needs six molecules of water + six molecules of carbon dioxide and light to enter into a reaction. This results in the formation of six molecules of oxygen and glucose in a chemical process. Glucose is glucose which the plant uses as source material for the synthesis of fats and proteins. Six molecules of oxygen are just a "necessary evil" for the plant, which it delivers to the environment through the closing cells.

As already mentioned, carbohydrates are the most important direct organic product of photosynthesis in most green plants. Little free glucose is formed in plants; instead, glucose units are linked to form starch, or combined with fructose, another sugar, to form sucrose.

Photosynthesis produces more than just carbohydrates., as it was once thought, but also:

amino acids;
proteins;
lipids (or fats);
pigments and other organic components of green tissues.

Minerals supply the elements (eg, nitrogen, N; phosphorus, P; sulfur, S) needed to form these compounds.

Chemical bonds are broken between oxygen (O) and carbon (C), hydrogen (H), nitrogen and sulfur, and new compounds are formed in products that include gaseous oxygen (O 2 ) and organic compounds. To break bonds between oxygen and other elements (such as water, nitrate, and sulfate) require more energy than is released when new bonds are formed in the products. This difference in binding energy explains most light energy stored as chemical energy in organic products produced during photosynthesis. Additional energy is stored when creating complex molecules from simple ones.

Factors affecting the rate of photosynthesis

The rate of photosynthesis is determined by the rate of oxygen production, either per unit mass (or area) of green plant tissues, or per unit weight of total chlorophyll.

The amount of light, carbon dioxide supply, temperature, water supply and mineral availability are the most important factors. environment, which affect the rate of photosynthesis reaction in terrestrial installations. Its speed is also determined by the plant species and its physiological state, such as its health, maturity and flowering.

Photosynthesis takes place exclusively in the chloroplasts (Greek chlorine = green, sheet-like) of the plant. Chloroplasts are predominantly found in palisades, but also in spongy tissue. On the underside of the leaf are blocking cells that coordinate the exchange of gases. CO 2 flows into the intercellular cells from the outside.

Water needed for photosynthesis, transports the plant from the inside through the xylem into the cells. Green chlorophyll ensures the absorption of sunlight. After the carbon dioxide and water are converted into oxygen and glucose, the closing cells open up and release oxygen into the environment. Glucose remains in the cell and is converted by the plant, among others, into starch. The strength is compared with the glucose polysaccharide and is only slightly soluble, so even in high water losses in the strength of plant residues.

Importance of photosynthesis in biology

Of the light received by the sheet, 20% is reflected, 10% is transmitted and 70% is actually absorbed, of which 20% is dissipated in heat, 48% is lost in fluorescence. About 2% remains for photosynthesis.

Through this process, plants play an indispensable role on the surface of the Earth; in fact, green plants with some groups of bacteria are the only living beings capable of producing organic substances from mineral elements. It is estimated that every year 20 billion tons of carbon are fixed by land plants from carbon dioxide in the atmosphere and 15 billion by algae.

Green plants are the main primary producers, the first link in the food chain; non-chlorophyll plants and herbivores and carnivores (including humans) are completely dependent on the photosynthesis reaction.

Simplified definition of photosynthesis is to convert light energy from the sun into chemical energy. This photonic carbohydrate biosynthesis is produced from carbon dioxide CO2 using light energy.

That is, photosynthesis is the result of chemical activity(synthesis) of chlorophyll plants, which produce the main biochemical organic substances from water and mineral salts due to the ability of chloroplasts to capture part of the sun's energy.

There are three types of plastids:

chloroplasts- green, function - photosynthesis
chromoplasts- red and yellow, are dilapidated chloroplasts, can give a bright color to the petals and fruits.
leucoplasts- colorless, function - stock of substances.

The structure of chloroplasts

covered with two membranes. The outer membrane is smooth, the inner one has outgrowths inside - thylakoids. Stacks of short thylakoids are called grains, they increase the area of the inner membrane in order to accommodate as many photosynthesis enzymes as possible on it.

The internal environment of the chloroplast is called the stroma. It contains circular DNA and ribosomes, due to which chloroplasts independently make some of the proteins for themselves, therefore they are called semi-autonomous organelles. (It is believed that earlier plastids were free bacteria that were absorbed by a large cell, but not digested.)

Photosynthesis (simple)

In green leaves in the light
In chloroplasts with chlorophyll
From carbon dioxide and water
Glucose and oxygen are synthesized.

Photosynthesis (medium difficulty)

1. Light phase.
Occurs in the light in the grains of chloroplasts. Under the action of light, decomposition (photolysis) of water occurs, oxygen is obtained, which is emitted, as well as hydrogen atoms (NADP-H) and ATP energy, which are used in the next stage.

2. Dark phase.
It occurs both in the light and in the dark (light is not needed), in the stroma of chloroplasts. From carbon dioxide obtained from the environment and hydrogen atoms obtained in the previous stage, glucose is synthesized due to the energy of ATP obtained in the previous stage.

1. Establish a correspondence between the process of photosynthesis and the phase in which it occurs: 1) light, 2) dark. Write the numbers 1 and 2 in the correct order.
A) the formation of NADP-2H molecules
B) release of oxygen
C) synthesis of a monosaccharide
D) synthesis of ATP molecules
D) the addition of carbon dioxide to a carbohydrate

Answer

2. Establish a correspondence between the characteristic and the phase of photosynthesis: 1) light, 2) dark. Write the numbers 1 and 2 in the correct order.
A) photolysis of water
B) carbon dioxide fixation
C) splitting of ATP molecules
D) excitation of chlorophyll by light quanta
D) glucose synthesis

Answer

3. Establish a correspondence between the process of photosynthesis and the phase in which it occurs: 1) light, 2) dark. Write the numbers 1 and 2 in the correct sequence.
A) the formation of NADP * 2H molecules
B) release of oxygen
B) glucose synthesis
D) synthesis of ATP molecules
D) carbon dioxide recovery

Answer

4. Establish a correspondence between the processes and the phase of photosynthesis: 1) light, 2) dark. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) polymerization of glucose
B) carbon dioxide binding
B) ATP synthesis
D) photolysis of water
E) the formation of hydrogen atoms
E) glucose synthesis

Answer

5. Establish a correspondence between the phases of photosynthesis and their characteristics: 1) light, 2) dark. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) photolysis of water is carried out
B) ATP is formed
B) oxygen is released into the atmosphere
D) proceeds with the expenditure of ATP energy
D) Reactions can take place both in the light and in the dark.

Answer

6 Sat. Establish a correspondence between the phases of photosynthesis and their characteristics: 1) light, 2) dark. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) restoration of NADP +
B) transport of hydrogen ions across the membrane
B) takes place in the grains of chloroplasts
D) carbohydrate molecules are synthesized
D) chlorophyll electrons move to a higher energy level
E) ATP energy is consumed

Answer

SHAPING 7:
A) movement of excited electrons
B) conversion of NADP-2R to NADP+
C) oxidation of NADP H
D) molecular oxygen is formed
D) processes occur in the stroma of the chloroplast

Analyze the table. Fill in the blank cells of the table using the concepts and terms given in the list. For each lettered cell, select the appropriate term from the list provided.
1) thylakoid membranes
2) light phase
3) fixation of inorganic carbon
4) water photosynthesis
5) dark phase
6) cell cytoplasm

Answer

Analyze the table "Reactions of photosynthesis". For each letter, select the appropriate term from the list provided.
1) oxidative phosphorylation
2) oxidation of NADP-2H
3) thylakoid membranes
4) glycolysis
5) addition of carbon dioxide to pentose
6) oxygen formation
7) the formation of ribulose diphosphate and glucose
8) synthesis of 38 ATP

Answer

Choose three options. The dark phase of photosynthesis is characterized by
1) the course of processes on the inner membranes of chloroplasts
2) glucose synthesis
3) carbon dioxide fixation
4) the course of processes in the stroma of chloroplasts
5) the presence of water photolysis
6) the formation of ATP

Answer

1. The signs listed below, except for two, are used to describe the structure and functions of the depicted cell organoid. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.

2) accumulates ATP molecules
3) provides photosynthesis

5) has semi-autonomy

Answer

2. All the signs listed below, except for two, can be used to describe the cell organoid shown in the figure. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) single-membrane organoid
2) consists of cristae and chromatin
3) contains circular DNA
4) synthesizes its own protein
5) capable of division

Answer

All the features below, except for two, can be used to describe the structure and functions of the chloroplast. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) is a two-membrane organoid
2) has its own closed DNA molecule
3) is a semi-autonomous organoid
4) forms a division spindle
5) filled with cell sap with sucrose

Answer

Choose one, the most correct option. Cellular organelle containing a DNA molecule
1) ribosome
2) chloroplast
3) cell center
4) Golgi complex

Answer

Choose one, the most correct option. In the synthesis of what substance do hydrogen atoms participate in the dark phase of photosynthesis?
1) NADF-2N
2) glucose
3) ATP
4) water

Answer

All the signs below, except for two, can be used to determine the processes of the light phase of photosynthesis. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) photolysis of water

4) formation of molecular oxygen

Answer

Choose two correct answers from five and write down the numbers under which they are indicated. In the light phase of photosynthesis in the cell
1) oxygen is formed as a result of the decomposition of water molecules
2) carbohydrates are synthesized from carbon dioxide and water
3) polymerization of glucose molecules occurs with the formation of starch
4) ATP molecules are synthesized
5) the energy of ATP molecules is spent on the synthesis of carbohydrates

Answer

Choose one, the most correct option. What cell organelle contains DNA
1) vacuole
2) ribosome
3) chloroplast
4) lysosome

Answer

Insert in the text "Synthesis of organic substances in a plant" the missing terms from the proposed list, using digital symbols for this. Write down the chosen numbers in the order corresponding to the letters. Plants store the energy they need to survive in the form of organic matter. These substances are synthesized during __________ (A). This process takes place in leaf cells in __________ (B) - special green plastids. They contain a special green substance - __________ (B). A prerequisite for the formation of organic substances in addition to water and carbon dioxide is __________ (D).
List of terms:
1) breathing
2) evaporation
3) leucoplast
4) food
5) light
6) photosynthesis
7) chloroplast
8) chlorophyll

Answer

Choose one, the most correct option. In cells, the primary synthesis of glucose occurs in
1) mitochondria
2) endoplasmic reticulum
3) Golgi complex
4) chloroplasts

Answer

Choose one, the most correct option. Oxygen molecules in the process of photosynthesis are formed due to the decomposition of molecules
1) carbon dioxide
2) glucose
3) ATP
4) water

Answer

Choose one, the most correct option. Are the following statements about photosynthesis correct? A) In the light phase, the energy of light is converted into the energy of the chemical bonds of glucose. B) Dark phase reactions occur on thylakoid membranes, into which carbon dioxide molecules enter.
1) only A is true
2) only B is true
3) both statements are correct
4) both judgments are wrong

Answer

1. Set the correct sequence of processes occurring during photosynthesis. Write down the numbers under which they are indicated in the table.
1) Use of carbon dioxide
2) Oxygen formation
3) Synthesis of carbohydrates
4) Synthesis of ATP molecules
5) Excitation of chlorophyll

Answer

2. Set the correct sequence of photosynthesis processes.
1) conversion of solar energy into ATP energy
2) the formation of excited chlorophyll electrons
3) carbon dioxide fixation
4) starch formation
5) conversion of ATP energy into glucose energy

Answer

3. Set the sequence of processes occurring during photosynthesis. Write down the corresponding sequence of numbers.

2) ATP breakdown and energy release
3) glucose synthesis
4) synthesis of ATP molecules
5) excitation of chlorophyll

Answer

Choose three features of the structure and functions of chloroplasts
1) inner membranes form cristae
2) many reactions take place in grains
3) glucose synthesis occurs in them
4) are the site of lipid synthesis
5) consist of two different particles
6) two-membrane organelles

Answer

Choose three correct answers from six and write down the numbers under which they are indicated. The following processes occur in the chloroplasts of plant cells:
1) hydrolysis of polysaccharides
2) breakdown of pyruvic acid
3) photolysis of water
4) the breakdown of fats to fatty acids and glycerol
5) carbohydrate synthesis
6) ATP synthesis

Answer

Identify three true statements from the general list, and write down the numbers under which they are indicated in the table. During the light phase of photosynthesis,
1) photolysis of water
2) reduction of carbon dioxide to glucose
3) the synthesis of ATP molecules due to the energy of sunlight
4) the combination of hydrogen with the carrier NADP +
5) the use of energy of ATP molecules for the synthesis of carbohydrates

Answer

All of the features listed below, except for two, can be used to describe the light phase of photosynthesis. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) a by-product is formed - oxygen
2) occurs in the stroma of the chloroplast
3) carbon dioxide binding
4) ATP synthesis
5) photolysis of water

Answer

Choose one, the most correct option. The process of photosynthesis should be considered as one of the important links in the carbon cycle in the biosphere, since during its
1) plants involve carbon from inanimate nature into living
2) plants release oxygen into the atmosphere
3) organisms release carbon dioxide during respiration
4) industrial production replenishes the atmosphere with carbon dioxide

Answer

Establish a correspondence between the stages of the process and processes: 1) photosynthesis, 2) protein biosynthesis. Write the numbers 1 and 2 in the correct order.
A) release of free oxygen
B) the formation of peptide bonds between amino acids
C) mRNA synthesis on DNA
D) translation process
D) restoration of carbohydrates
E) conversion of NADP + to NADP 2H

Answer

Select the cell organelles and their structures involved in the process of photosynthesis.
1) lysosomes
2) chloroplasts
3) thylakoids
4) grains
5) vacuoles
6) ribosomes

Answer

The terms listed below, except for two, are used to describe plastids. Identify two terms that “fall out” from the general list, and write down the numbers under which they are indicated in the table.
1) pigment
2) glycocalyx
3) grana
4) krista
5) thylakoid

Answer

All of the following features, except for two, can be used to describe the process of photosynthesis. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated in response.
1) Light energy is used to carry out the process.
2) The process occurs in the presence of enzymes.
3) The central role in the process belongs to the chlorophyll molecule.
4) The process is accompanied by the breakdown of the glucose molecule.
5) The process cannot occur in prokaryotic cells.

Answer

1. The concepts listed below, except for two, are used to describe the dark phase of photosynthesis. Identify two concepts that “fall out” from the general list, and write down the numbers under which they are indicated.
1) carbon dioxide fixation
2) photolysis
3) oxidation of NADP 2H
4) grana
5) stroma

Answer

2. All the signs listed below, except for two, are used to describe the dark phase of photosynthesis. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) oxygen formation
2) carbon dioxide fixation
3) use of ATP energy
4) glucose synthesis
5) excitation of chlorophyll

Answer

The signs listed below, except for two, are used to describe the structure and functions of the depicted cell organoid. Identify two signs that “fall out” from the general list, and write down the numbers under which they are indicated.
1) splits biopolymers into monomers
2) accumulates ATP molecules
3) provides photosynthesis
4) refers to two-membrane organelles
5) has semi-autonomy

Answer

Establish a correspondence between the processes and their localization in chloroplasts: 1) stroma, 2) thylakoid. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) the use of ATP
B) photolysis of water
B) excitation of chlorophyll
D) the formation of pentose
D) electron transfer along the chain of enzymes

Answer