History of the discovery The first to discover that plants emit oxygen was the English chemist Joseph Priestley around In 1817, two French chemists, Peltier and Cavantou, isolated a green substance from leaves and called it chlorophyll. In 1845, German physicist Robert Mayer argued that green plants convert energy from sunlight into chemical energy.
History of discovery In the 20th century. It has been found that the process of photosynthesis begins in light in the chlorophyll photoreceptors, but many of the subsequent stages can occur in the dark. In 1941, American biochemist Melvin Calvin showed that the primary process of photosynthesis consists of photolysis of water molecules, resulting in the formation of oxygen and hydrogen, which are used to reduce carbon dioxide to organic substances.
Chloroplasts Green plastids that are found in plant cells. With their help, photosynthesis occurs. Chloroplasts contain chlorophyll. They are double-membrane organelles. Under the double membrane there are thylakoids (membrane formations in which the electron transport chain of chloroplasts is located). Thylakoids of higher plants are grouped into grana, which are stacks of flattened and closely pressed disc-shaped thylakoids. The space between the chloroplast membrane and the thylakoids is called the stroma. The stroma contains chloroplast molecules RNA, DNA, ribosomes, and starch grains.
The Importance of Photosynthesis The process of photosynthesis is the basis of nutrition for all living things and also supplies humanity with fuel, fiber and countless useful chemical compounds. About % of the dry weight of the crop is formed from carbon dioxide and water combined from the air during photosynthesis. Humans use about 7% of photosynthetic products in food, as animal feed and in the form of fuel and building materials
Pyrococcus furiosus is a typical inhabitant of hot underwater springs and heated rocks. Grows at temperatures from 70 to 103°C. Thermococcus is one of the characteristic inhabitants of the hot deep layers of the earth's crust. Prefers temperatures from 60 to 100°C. At one pole of the cell there is a bundle of long flagella (as in the related Pyrococcus). Chemosynthetics:
ChemosyntheticsSource of energy Iron bacteria (Geobacter, Gallionella) oxidize divalent iron to ferric iron. Fe 2+ Fe 3+ + energy Sulfur bacteria (Desulfuromonas, Desulfobacter, Beggiatoa) oxidize hydrogen sulfide to molecular sulfur or to sulfuric acid salts. H 2 SSH 2 SO 4 + energy Nitrifying bacteria (Nitrosomonas, Nitrosococcus) oxidize ammonia, formed during the decay of organic substances, to nitrous and nitric acids, which form nitrites and nitrates. NH 3 HNO 2 HNO 3 + energy
The importance of Chemosynthesis The role of chemosynthetics for all living beings is very great, since they are an indispensable link in the natural cycle of the most important elements: sulfur, nitrogen, iron, etc. Chemosynthetics are also important as natural consumers of such toxic substances as ammonia and hydrogen sulfide. Nitrifying bacteria are of great importance; they enrich the soil with nitrites and nitrates; plants absorb nitrogen mainly in the form of nitrates. Some chemosynthetics (in particular, sulfur bacteria) are used for wastewater treatment.
Slide presentation
Slide text: METABOLISM chemosynthesis Prepared by Golubeva S.V. Lesosibirsk part 4
Slide text: In 1977, a fantastic picture appeared to the eyes of geologists who descended in a submersible into the sea near the Galapagos Islands and reached the bottom at a depth of 2.6 km. The rays of searchlights revealed a fantastic riot of life from the darkness of the eternal night. In the flickering streams of warm water in the recesses of the bottom, like buns in a basket, huge snow-white bivalves lay in dozens, large brown mussels hung in clusters, white crayfish and crabs wandered in herds, strange tubes stuck out worms with red plumes of tentacles... And all this at a depth where there should be a “benthic desert”! This is how people first saw the fauna of hydrotherms, deep-sea “oases” on the ocean floor.
Slide text: And this is where photosynthesis is impossible, where producer plants, which are the first link in the food chain, are not found. The shimmering water in which the inhabitants of the Garden of Eden bathed (this is the name given to the open field) is highly saturated with hydrogen sulfide. Such towers with black “smoke” emanating from them are now known as black smokers. Mid-ocean ridges occur at the junction of giant lithospheric plates, where the hot mantle of the Earth comes close to the surface. Sea water seeps into the rocks through cracks. The heat of nearby magma heats it up to 300–400 °C, and it begins to dissolve sulfur compounds and other substances from the surrounding rocks with terrible force. Then this superheated solution bursts upward and shoots out from the bottom in fountains. Mixing with cold (2–3 °C) bottom water, it quickly cools down, and some substances dissolved in it begin to fall back. For example, from dissolved sulfates small crystals of sulfides, insoluble and black, are obtained. Myriads of them are suspended in a stream gushing from the bottom, and this stream begins to resemble thick black smoke, very similar to the smoke from burning rubber. The sulfide powder settles down, and from it, like stalagmites in caves, black towers begin to be built, growing from the bottom, covered with a red coating of sulfurous ocher. Such towers with black “smoke” emanating from them are now known as black smokers.
Slide text: What do the inhabitants of these communities eat? Hydrogen sulfide contains a sulfur atom in a reduced form and is easily oxidized, releasing a large amount of energy. In the presence of certain enzyme systems, this energy can be utilized by using it for the synthesis of ATP. And the energy of ATP, in turn, can be used to restore carbon and synthesize “regular” nutrients (carbohydrates) from carbon dioxide. A number of bacterial species have the necessary enzyme systems. Like green plants, they are autotrophic organisms that independently create organic matter from inorganic matter. However, if the plants belong to the group of phototrophs, i.e. use the energy of sunlight (photosynthesis) for the initial synthesis of ATP, then sulfur bacteria live through chemosynthesis and are called chemotrophs. Bacteria also come into play, working with hydrogen, nitrogen compounds and methane. And they all synthesize organics, organics, organics... Of course, in the hungry depths there are immediate consumers for this organic matter.
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Slide text: Back in 1887, Russian microbiologist S.N. Winogradsky discovered bacterial chemosynthesis. It turned out that some bacteria also know how to create new organic matter from inorganic matter, but they spend energy on this, obtained not from sunlight, but from chemical reactions during the oxidation of ammonia, hydrogen, sulfur compounds, ferrous iron, etc. Born in 1853 in Russia Died 1953 in France
Slide text: Oxygen-free (anaerobic) respiration Bacteria are important in nature and are capable of obtaining energy from inorganic compounds in the absence of oxygen. Denitrifying bacteria are able to reduce nitrates to nitrogen gas and nitrous oxide: 10H + 2H+ + 2NO3- N2 + 6H2O + ATP In the absence of these bacteria, the nitrogen content in the atmosphere would decrease and the growth of plants and biomass on Earth would stop. Sulfate-reducing bacteria are capable of producing hydrogen sulfide from sulfate: 8H + SO42- H2S + 2H2O + 2OH- + ATP For this reaction, bacteria take hydrogen from the products of glycolysis. The energy that is stored in this process is used for the synthesis of organic compounds. These bacteria are found in hydrogen sulfide mud (for example, in the Black Sea at a depth of more than 200 m). Most sulfur deposits are biogenic sulfur deposits. Anoxic (anaerobic) respiration Anaerobic chemoautotrophs The anaerobic pathway of metabolism and energy is characteristic mainly of bacteria. Some of them use organic compounds as donors of hydrogen and electrons and are thus heterotrophs, others use inorganic compounds for these purposes, and they obtain carbon from carbon dioxide and are thus anaerobic chemoautotrophs.
Slide No. 10
Slide text: Molecular oxygen that appeared in the Earth's atmosphere acted as a strong oxidizing agent. Bacteria were among the first to use aerobic metabolism, oxidizing inorganic compounds of nitrogen, sulfur, and iron. Nitrifying bacteria - oxidize ammonia to nitrates. NH4+ nitrite bacteria NO2- nitrate bacteria NO3- Despite the presence of oxygen in ammonia oxidation reactions, the energy balance of nitrifying bacteria turned out to be very low. Sulfur bacteria are capable of oxidizing sulfur compounds, forming sulfates at the end of the reaction: S2- + 2O2 SO42- or S2- + SO2 + 2H2O SO42- + 4H+ Many sulfur bacteria live in extreme conditions of hot sulfur volcanic springs. They can withstand temperatures up to 750C and are capable of oxidizing sulfur or hydrogen sulfide to sulfuric acid. These bacteria are called thermophiles. Iron bacteria are capable of oxidizing divalent iron to trivalent iron. FeS2 + 3SO3 + H2O FeSO4 + H2SO4. Iron bacteria live in mine waters containing various metal compounds, including iron. Man uses the properties of these bacteria in the enrichment of ores to obtain copper, zinc, and molybdenum. Aerobic chemoautotrophs In the process of evolution, these bacteria were forced to oxidize inorganic substrates to obtain energy, and the only source of carbon for them was carbon dioxide. Therefore, based on the type of nutrition, these bacteria can be classified as a special group of aerobic chemoautotrophs.
Slide No. 11
Slide text: http://www.moscowuniversityclub.ru/article/img/11395_57360935.gif background http://www.photolib.noaa.gov/bigs/nur04510.jpg SMOKERS http://hartm242.files.wordpress.com /2011/06/chemosynthesis_lg.jpg molecules http://www.iemrams.spb.ru/russian/director/vinogradski.htm Vinogradsky S.N. http://bio.1september.ru/2001/24/6.gif food chain http://tupoebydlo.livejournal.com/2998.html live journal
MARCELLO MALPIGHI 1667If you tear off pumpkin seedlings
germ leaves, then the plant
stops developing.
That is, for the development of plants
sunlight needed
Joseph Priestley 1772
JOSEPH PRIESTLEY 1772Under the glass cover, under which it went out
candle he placed mint and left on
for a while. The plant did not die, but
on the contrary, it gave new leaves. When in
some time Priestley brought a splinter there,
then it flashed brightly, which indicates the presence
under an oxygen hood.
Priestley's experience
PRYESTLEY'S EXPERIENCELeaf chloroplast structure
STRUCTURE OF CHLOROPLAST LEAFSize 10 microns. Disc shape. The number varies from 1
up to 40. The inner membrane forms flat bubbles -
thylakoids. Stacks of thylakoids are grana. Enzymes,
reducing carbon dioxide to glucose are in
stroma.
The main pigment of chloroplasts is chlorophyll
MAIN PIGMENT OF CHLOROPLASTS CHLOROPHYLLThe structure resembles a pigment
human and animal erythrocytes – heme.
The structure of chlorophyll
STRUCTURE OF CHLOROPHYLLThe basis is
porphyrin ring, in
which has 4 pyrrole
heterocycle connected
between themselves.
Pyrrole rings
coordinated with the atom
magnesium
Long side
hydrophobic chain (C20H39)
serves to secure
molecules in the lipid layer
thylakoid membranes
and to give it
certain orientation.
Forms of chlorophylls
FORMS OF CHLOROPHYLLSpectra of chlorophylls A and B
are in different areas.
Photosynthesis also involves
carotenoids and phycobilins
(as auxiliary pigments in
higher plants and algae)
Olympiad task
OLYMPICS TASKchloroplasts. Each chloroplast contains pigment
a system represented by two types of pigments: green -
………………………….……………..and yellow –
……………………………………………. During the process of photosynthesis, light
energy before conversion to chemical energy
absorbed by pigments. Pigments localized in
plastids, absorb light in the visible part of the spectrum
……………………… nm. Pigments absorb visible light without
completely, but selectively, i.e. each pigment has its own
characteristic absorption spectrum. The picture shows
absorption spectra of chlorophyll pigments, indicate which one
spectrum - characteristic of which pigment Wavelength, nm.
Solution to the task
SOLUTION TO THE PROBLEMThe process of photosynthesis is impossible without
chloroplasts.
Each chloroplast contains a pigment system,
represented by two types of pigments:
green – (chlorophylls a and b) and yellow –
(carotenoids).
During the process of photosynthesis, light energy before
converted to chemical energy is absorbed
pigments. Pigments localized in plastids
absorb light from the visible part of the spectrum (380-720 nm).
Pigments do not completely absorb visible light, but
selectively, i.e. each pigment has its own characteristic
absorption spectrum. The figure shows the absorption spectra of pigments
chlorophyll, indicate which spectrum - typical for which
pigment:
1. Chlorophyll a
2. Chlorophyll b
3. Carotenoids
General scheme of photosynthesis
GENERAL SCHEME OF PHOTOSYNTHESISFS 1 (P700) – photochemical center, P –
pigment absorbing wavelength 700 nm
The resulting “hole” from an electron
filled out from FS 2 (P680).
FS 2 compensates for electrons thanks to
photolysis of water. Oxygen is a by-product
product of this reaction and is released into
atmosphere (this is the oxygen we
breathe) LIGHT PHASE (EXPLANATIONS TO PREVIOUS SLIDE)
Photolysis occurs on the inner membrane
thylakoid and hydrogen ions accumulate
there (H+ - reservoir)
Through special proton channels, ions
hydrogen passes into the stroma of the chloroplast
The channels are associated with the enzyme ATP synthesis, which catalyzes the synthesis of ATP
NADP+ accepts hydrogen ions and
reduced to NADP*H
Processes take place in the light phase
PROCESSES OCCUR IN THE LIGHT PHASE1. Chlorophyll stimulation and movement
electrons in photosynthetic systems
2. Photolysis of water and formation of oxygen
3. Synthesis of ATP molecules (PSII)
4. The combination of hydrogen with a special
NADP+ transporter and formation
NADP *2H
(nicotinamide adenine nucleotide phosphate
refurbished (FS I)
Melvin Calvin studied the dark phase of photosynthesis
MELVIN CALVIN STUDYED THE DARK PHASEPHOTOSYNTHESIS
dark processes
photosynthesis reactions
opened in 1957
In 1961 - received
Nobel Prize in
field of chemistry "for
uptake research
carbon dioxide
plants"
Calvin cycle
CALVIN CYCLEDuring the dark stage
DURING THE DARK STAGE1. Two trioses are used for glucose synthesis
2. Trioses can be used for synthesis
amino acids, glycerol and higher fatty acids
acids
3. Some trioses stimulate cycle repetition
Calvin
6CO2 + 12 NADP*2H + 12 ATP = C6H12O6 +
12 NADP+ + 12 ADP + 12 Fn
Dark phase of photosynthesis (stroma)
DARK PHASE OF PHOTOSYNTHESIS (STROMA)1. From carbon dioxide coming from
atmosphere and water are carried out
cyclic processes (Calvin cycle)
2. Carbon reduction occurs
hydrogen NADP *2H due to the energy of ATP
3. Glucose synthesis
Since in each cycle only
1 molecule of CO2, then to get the glucose cycle
must be repeated 6 times
The essence of photosynthesis
THE ESSENCE OF PHOTOSYNTHESISEffect on the rate of photosynthesis
INFLUENCE ON THE RATE OF PHOTOSYNTHESIS1. Light wavelength (blue and red parts are best
spectrum)
2. Degree of illumination
3. CO2 concentration (in greenhouses the rate is higher)
4. Temperature (25-30 C is optimal)
5. Availability of water
The meaning of photosynthesis
THE IMPORTANCE OF PHOTOSYNTHESIS1.
2.
Products of photosynthesis – organic substances –
used by organisms:
To build cells
As a source of energy for life processes
Man uses substances created by plants:
1.
2.
3.
As food (fruits, seeds, etc.)
As energy sources (coal, peat, wood)
As a building material in the production of furniture, etc.
COMPARATIVE CHARACTERISTICS
Sign
Photosynthesis
Reaction equation 6 CO2 + 6H2O +
light energy =
C6H12O6 + 6 O2
Initial substances Carbon dioxide,
water
Reaction products
Organic
substances, oxygen
Breath
C6H12O6 + 6 O2 =
6 CO2 + 6H2O +
energy (ATP)
Organic
substances, oxygen
Carbon dioxide,
water
Value in
the cycle
substances
Decomposition
organic
substances up to
inorganic
Synthesis
organic
substances from
inorganic
Comparative characteristics of photosynthesis and respiration of eukaryotes
COMPARATIVE CHARACTERISTICSPHOTOSYNTHESIS AND RESPIRATION OF EUKARYOTES
Sign
Photosynthesis
Breath
Conversion of energy
Conversion of energy
light into energy
chemical bonds
organic matter
Conversion of energy
chemical bonds
organic matter in
energy
macroergic
ATP bonds
Key Stages
Light and dark
phases (including cycle
Calvin)
Incomplete oxidation
(glycolysis) and complete
oxidation (cycle
Krebs)
Leak location
process
Chloroplasts (granas and
stroma)
Hyaloplasm (incomplete
oxidation) and
mitochondria - cristae and
matrix (full
oxidation)
2S +3O2 + 2 H2O = 2H2SO4 + Q
For two reactions 666 kJ/mol.
Sulfur bacteria live in the Black Sea on
depth 200 m. Hydrogen bacteria
HYDROGEN BACTERIA
2H2 + O2 = 2H2O + Q
All energy in these processes is stored in
in the form of ATP Iron bacteria (Crenothrix and Leptothrix)
IRON BACTERIA (CRENOTHRIX AND LEPTOTHRIX)
4FeCO3 + O2 + H2O = 4Fe(OH)3 + 4CO2 + Q
All chemosynthetics are obligate
aerobes because they use oxygen
air The meaning of chemosynthesis
THE IMPORTANCE OF CHEMOSYNTHESIS
1. Nitrifying and denitrifying
participate in the nitrogen cycle, increase
soil fertility
2. Nodule bacteria (rhizobium),
living on the roots of leguminous plants
bind atmospheric
nitrogen The meaning of chemosynthesis
THE IMPORTANCE OF CHEMOSYNTHESIS
Iron bacteria participated in the formation
iron and manganese ores of the planet
Hydrogen bacteria are used for
obtaining food and feed protein
Hydrogen bacteria are used for
atmospheric regeneration (for example, at
water treatment plants for biological treatment
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Slide captions:
(autotrophic nutrition) Biology teacher Volodina T.O Volginskaya Secondary School - 2012 Chemosynthesis
A method of autotrophic nutrition in which the source of energy for the synthesis of organic matter is the oxidation processes of various inorganic substances: ammonia, hydrogen sulfide, sulfur, hydrogen, iron compounds…. The source of hydrogen is water chemosynthesis
Chemosynthesis was discovered in 1887 by Sergei Nikolaevich Vinogradsky
Capable of oxidizing ammonia formed during the decay of organic residues, first to nitrous and then to nitric acid. 2NH3 + 3O2 = 2HNO2 +2H2O+663 kJ 2 HNO2 + O2 = 2HNO3 + 142 kJ Nitric acid reacts with mineral compounds in the soil to form nitrates, which are well absorbed by plants Nitrifying bacteria
They oxidize hydrogen sulfide and accumulate sulfur in their cells: 2 H2S + O2 = 2 H2O + 2 S + 272 kJ With a lack of hydrogen sulfide, bacteria further oxidize sulfur to sulfuric acid: 2 S + 3 O2 + 2 H2O = 2H2SO4 + 636 kJ Colorless sulfur bacteria
Oxidize divalent iron to ferric iron 4 FeCO3 + O2 + 6 H2O = 4 Fe(OH)3 + 4 CO2 + 324 kJ Iron bacteria
They use the energy released during the oxidation of molecular hydrogen 2H2O + O2 = 2 H2O + 235 kJ Hydrogen bacteria
Nitrifying bacteria carry out the nitrogen cycle in the biosphere. Ecological role of chemosynthesis
By forming sulfuric acid, they contribute to the destruction and weathering of rocks; Destroy stone and metal structures Leach ore and sulfur deposits Purify industrial wastewater Sulfur bacteria
Form Fe(OH)3 accumulation of which forms swamp iron ore Iron bacteria
To obtain cheap feed and food protein To regenerate the atmosphere in closed life support systems (Oasis - 2 system, on the Soyuz - 3 spacecraft, 1973) Hydrogen bacteria
On the topic: methodological developments, presentations and notes
Methodological development of the lesson "Photosynthesis. Chemosynthesis".
Methodological development of a lesson in 9th grade on the topic: “Photosynthesis. Chemosynthesis.” The purpose of the lesson: to study the features of the metabolism of autotrophic organisms using the example of the processes of photosynthesis and chemosynthesis. Students...
presentation photosynthesis and chemosynthesis
Presentation on biology for 9th grade students. Line of V. Pasechnik. This presentation discusses the features of the processes of photosynthesis and chemosientesis, their role....
"Photosynthesis. Chemosynthesis"
The purpose of the lesson: to study the features of the metabolism of autotrophic organisms using the example of the photosynthesis process. Objectives: educational - to reveal the features of the photosynthesis process, the essence of the light and dark phases...
Chemosynthesis
Chemosynthesis is a method of autotrophic nutrition in which the oxidation reactions of inorganic compounds serve as the source of energy for the synthesis of organic substances from CO2. This option for obtaining energy is used only by bacteria or archaea. The phenomenon of chemosynthesis was discovered in 1889 by Russian scientist S. N. Vinogradsky,
It should be noted that the energy released in the oxidation reactions of inorganic compounds cannot be directly used in the assimilation process. First, this energy is converted into the energy of macroenergetic bonds of ATP and only then is spent on the synthesis of organic compounds.
Chemolithophthotrophic organisms
Iron bacteria (Geobacter, Gallionella) oxidize divalent iron to ferric iron.
Sulfur bacteria (Desulfuromonas, Desulfobacter, Beggiatoa) oxidize hydrogen sulfide to molecular sulfur or to sulfuric acid salts.
Nitrifying bacteria (Nitrobacteraceae, Nitrosomonas, Nitrosococcus) oxidize ammonia formed during the decay of organic matter, nitrogenous and nitric acids, which, interacting with soil minerals, form nitrites and nitrates.
Thionic bacteria (Thiobacillus, Acidithiobacillus) are capable of oxidizing thiosulfates, sulfites, sulfides and molecular sulfur to sulfuric acid (often with a significant decrease in the pH of the solution), the oxidation process differs from that of sulfur bacteria (in particular, in that thionic bacteria do not deposit intracellular sulfur). Some representatives of thionic bacteria are extreme acidophiles (able to survive and reproduce when the pH of the solution drops down to 2), capable of withstanding high concentrations of heavy metals and oxidizing metallic and divalent iron (Acidithiobacillus ferrooxidans) and leaching heavy metals from ores.
Hydrogen bacteria (Hydrogenophilus) are capable of oxidizing molecular hydrogen and are moderate thermophiles (grow at a temperature of 50 °C)
Distribution and ecological functions
Chemosynthetic organisms (for example, sulfur bacteria) can live in the oceans at great depths, in places where hydrogen sulfide escapes from fractures in the earth’s crust into the water. Of course, light quanta cannot penetrate water to a depth of about 3-4 kilometers (at this depth most ocean rift zones are located). Thus, chemosynthetics are the only organisms on earth that do not depend on the energy of sunlight.
On the other hand, ammonia, which is used by nitrifying bacteria, is released into the soil when plant or animal matter rots. In this case, the vital activity of chemosynthetics indirectly depends on sunlight, since ammonia is formed during the decomposition of organic compounds obtained from the energy of the Sun.
The role of chemosynthetics for all living beings is very great, since they are an indispensable link in the natural cycle of the most important elements: sulfur, nitrogen, iron, etc. Chemosynthetics are also important as natural consumers of such toxic substances as ammonia and hydrogen sulfide. Nitrifying bacteria are of great importance, they enrich the soil with nitrites - it is mainly in the form of nitrates that plants absorb nitrogen. Some chemosynthetics (in particular, sulfur bacteria) are used for wastewater treatment.
According to modern estimates, the biomass of the “underground biosphere,” which is located, in particular, under the seabed and includes chemosynthetic anaerobic methane-oxidizing archaebacteria, may exceed the biomass of the rest of the biosphere.