to carbohydrates.
Several studies were conducted using isotopes of radioactive elements to identify the various aspects of the photosynthetic process. A number of organisms like Chlorella , Stellaria media, Cladophora, Spirogyra, Rhodopseudomonas , sulfur bacteria, green plants like maize, etc have been used to understand the photosynthesis process over the years. Gas exchange studies, isotopic studies, light spectrum studies, radioactive studies, plant anatomical and physiological studies, studies involving roles of carbon dioxide and water, etc have all together opened the gates for our deeper understanding of this topic.
The 3 main factors that directly affect the photosynthesis process are:
Although there are many more corollary factors, these 3 are the most important ones.
Light is an essential factor for photosynthesis. It directly affects the rate of it. There are 3 different parameters that we should look into:
Carbon dioxide concentration is the major factor in determining the rate of photosynthesis. There is no carbon-dioxide enriching system in C3 plants like the C4 plants. So, if you increase the concentration of CO 2 in the system, the photosynthetic rate of C3 plants will increase as the CO 2 concentration increases. On the other hand, the photosynthetic yield of the C4 plant won’t increase in such a scenario.
Imagine an equal concentration (50-50%) of the two isotopes of carbon, C-12 and C-13, in the form of 12CO 2 and 13CO 2 , made available to both C3 and C4 plants. Now, can you tell which isotope of the carbon will be fixed more or less by the two types of photosynthetic organisms? Can you guess if there would be a “preferable” isotope between the two? Do you think C3 plants will fix the 12CO 2 and 13CO 2 equally or unequally? Or do you think the 12CO 2 and 13CO 2 incorporation would have a biased ratio in any of the two (C3/C4 plants)????
The answer to this lies in the major carbon fixing enzyme involved.
Choose the best answer.
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Last updated on July 15th, 2022
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What is photosynthesis.
It is the process by which green plants, algae, and certain bacteria convert light energy from the sun into chemical energy that is used to make glucose. The word ‘photosynthesis’ is derived from the Greek word phōs, meaning ‘light’ and synthesis meaning ‘combining together.’
Jan Ingenhousz, the Dutch-born British physician and scientist, discovered the process of photosynthesis.
Photosynthesis takes place mainly in the leaves of green plants and also in the stems of herbaceous plants as they also contain chlorophyll. Sometimes it also occurs in roots that contain chlorophyll like in water chestnut and Heart-leaved moonseed. Apart from plants, photosynthesis is also found to occur in blue-green algae.
It involves a chemical reaction where water, carbon dioxide, chlorophyll, and solar energy are utilized as raw materials (inputs) to produce glucose, oxygen, and water (outputs).
Photosynthesis occurs in two stages:
1) The Light-dependent Reaction
2) The Light-independent or Dark Reaction ( Calvin cycle )
Although all the above factors together interact to affect the rate of photosynthesis, each of them individually is also capable of directly influencing the process without the other factors and thus called limiting factors.
It serves two main purposes that are essential to support life on earth:
Ans. Photosynthesis is an endothermic reaction because it absorbs the heat of the sun to carry out the process.
Ans. The oxygen in photosynthesis comes from splitting the water molecules.
Ans. Chlorophyll is the main light-absorbing pigment in photosynthesis.
Ans. The role of water is to provide oxygen in the form of oxygen gas to the atmosphere.
Ans. Sunlight is the source of energy that drives photosynthesis.
Ans. The easiest way to measure the rate of photosynthesis is to quantify the carbon dioxide or oxygen levels using a data logger. The rate of photosynthesis can also be measured by determining the increase in the plant ’s biomass (weight).
Ans. Photosynthesis is an energy-requiring process occurring only in green plants, algae, and certain bacteria that utilizes carbon dioxide and water to produce food in the form of carbohydrates. In contrast, cellular respiration is an energy-releasing process found in all living organisms where oxygen and glucose are utilized to produce carbon dioxide and water.
Ans. Glucose produced in photosynthesis is used in cellular respiration to make ATP.
Article was last reviewed on Tuesday, April 21, 2020
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Course: middle school biology > unit 3, photosynthesis in organisms.
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Cells get nutrients from their environment, but where do those nutrients come from? Virtually all organic material on Earth has been produced by cells that convert energy from the Sun into energy-containing macromolecules. This process, called photosynthesis, is essential to the global carbon cycle and organisms that conduct photosynthesis represent the lowest level in most food chains (Figure 1).
Most living things depend on photosynthetic cells to manufacture the complex organic molecules they require as a source of energy. Photosynthetic cells are quite diverse and include cells found in green plants, phytoplankton, and cyanobacteria. During the process of photosynthesis, cells use carbon dioxide and energy from the Sun to make sugar molecules and oxygen. These sugar molecules are the basis for more complex molecules made by the photosynthetic cell, such as glucose. Then, via respiration processes, cells use oxygen and glucose to synthesize energy-rich carrier molecules, such as ATP, and carbon dioxide is produced as a waste product. Therefore, the synthesis of glucose and its breakdown by cells are opposing processes.
However, photosynthesis doesn't just drive the carbon cycle — it also creates the oxygen necessary for respiring organisms. Interestingly, although green plants contribute much of the oxygen in the air we breathe, phytoplankton and cyanobacteria in the world's oceans are thought to produce between one-third and one-half of atmospheric oxygen on Earth.
Chlorophyll A is the major pigment used in photosynthesis, but there are several types of chlorophyll and numerous other pigments that respond to light, including red, brown, and blue pigments. These other pigments may help channel light energy to chlorophyll A or protect the cell from photo-damage. For example, the photosynthetic protists called dinoflagellates, which are responsible for the "red tides" that often prompt warnings against eating shellfish, contain a variety of light-sensitive pigments, including both chlorophyll and the red pigments responsible for their dramatic coloration.
Photosynthesis consists of both light-dependent reactions and light-independent reactions . In plants, the so-called "light" reactions occur within the chloroplast thylakoids, where the aforementioned chlorophyll pigments reside. When light energy reaches the pigment molecules, it energizes the electrons within them, and these electrons are shunted to an electron transport chain in the thylakoid membrane. Every step in the electron transport chain then brings each electron to a lower energy state and harnesses its energy by producing ATP and NADPH. Meanwhile, each chlorophyll molecule replaces its lost electron with an electron from water; this process essentially splits water molecules to produce oxygen (Figure 5).
Once the light reactions have occurred, the light-independent or "dark" reactions take place in the chloroplast stroma. During this process, also known as carbon fixation, energy from the ATP and NADPH molecules generated by the light reactions drives a chemical pathway that uses the carbon in carbon dioxide (from the atmosphere) to build a three-carbon sugar called glyceraldehyde-3-phosphate (G3P). Cells then use G3P to build a wide variety of other sugars (such as glucose) and organic molecules. Many of these interconversions occur outside the chloroplast, following the transport of G3P from the stroma. The products of these reactions are then transported to other parts of the cell, including the mitochondria, where they are broken down to make more energy carrier molecules to satisfy the metabolic demands of the cell. In plants, some sugar molecules are stored as sucrose or starch.
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The photosystem, the process.
Photosynthesis is the process used by plants to convert sunlight into chemical energy that can be used to fuel the plants’ growth. The process is fueled by the sun and powered by the chloroplasts in the plants’ leaves. The process begins with the sun’s light energy breaking down water molecules into oxygen and hydrogen. The oxygen is released into the air and the hydrogen is used to power the conversion of carbon dioxide into glucose, which is the plant’s food.
Plants, like every other organism, need energy to live, grow and repair. Unlike heterotrophs – animals that consume food to synthesize energy – plants or autotrophs are self-reliant — they can make their own food, and therefore energy, by using the resources available in their surroundings. The resources include sunlight, water and carbon dioxide, and this incredible process is called photosynthesis.
The process is known as photo synthesis because, while water and carbon dioxide are the major ingredients required to cook the food, it is light that ignites the stove, and sunlight is the most abundant light that illuminates the planet.
A photosynthetic organism using the energy of photons ( photo-) , makes its own food (- synthesis ).
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A plant is essentially a highly efficient solar panel. It is replete with molecular structures that have evolved to soak up and absorb as much sunlight as possible.
These structures are in separate compartments of the cell called chloroplasts. Inside the chloroplasts are small towers of discs called grana, each disc is called thylakoid. In the membrane or lining of the thylakoids are a dense grid of various light absorbing molecules, the most notable of them, chlorophyll. The pigments, like any other pigments, absorb light of certain wavelengths and reflect the rest.
This is how pigments or colors are radiated. Majority of plants are green because they (the abundance of chlorophyll) reflect wavelengths that we associate with green while absorbing wavelengths that fall into the red and blue zones. But there are other pigments that absorb different wavelengths in the visible spectrum. Carotenoids are pigments that absorb in the blue to green wavelengths, reflecting orange, yellow and red wavelengths.
This is why leaves take on shades from orange to red during autumn , as they start losing their chlorophyll come at that time of the year. Some deep-sea algae (rhodophyta) are red in color due to a photosynthetic pigment called phycoerythrin and phycocyanin which absorb in blue to green region and reflect back red wavelengths.
These pigments are part of larger protein machines called photosystems. Plants have two photosystems – photosystem I (PSI) and photosystem II (PSII), each having a key chlorophyll-a molecule embedded in it, along with other accessory pigments. These accessory pigments collect light energy and pass it onto the main chlorophyll-a molecule. The photosystems are the main light harvesting machines in the chloroplasts that convert light energy to chemical energy that the cell can use to do build its food. Some algae and photosynthetic bacteria only have single photosystems.
Solar energy is used by the chloroplast to trigger a chemical reaction between the two reactants – water and carbon dioxide.
Also Read: Why Are Plants Red In Color At The Bottom Of The Ocean?
A plant obtains water from its roots through osmosis . From there, the water ascends through the stem and is transported to every part of the plant that requires it for a myriad of processes other than photosynthesis.
To ensure that plant doesn’t dry out due to evaporation, they evolved special pores, called stomata about 400 million years ago. Stomata allowed them to respire, exchanging gases like oxygen and carbon dioxide. However, the crucial development of pores came at the expense of losing water unnecessarily
The stomata inhale carbon dioxide exhaled by animals, which reacts with water in the presence of sunlight to create sugar (glucose), their food. However, the reaction unfolds in two parts.
The first part is called a light-dependent or simply, a light reaction, in which light breaks down water to produce oxygen molecules. These molecules are the same oxygen molecules that we breathe. They are exhaled through the stomata and dispersed into the air. The light energy absorbed by a pigment can be either simply dissipated as heat or be converted into another form of energy. We witness the latter in plants. The light reaction converts solar energy into chemical energy; the reaction also produces ATP (Adenosine Tri-Phosphate) and NADP + (Nicotinamide Adenine Dinucleotide Phosphate), organic compounds that become sources of energy for subsequent metabolic processes.
When light breaks down water at PSII. This releases two protons (H+) and oxygen, and two energized electrons which the chlorophyll-a in PSII accepts. These electrons are passed from PSII to other middle protein structures, like cytochrome bf, to PSI. There these two electrons get energized at PSI due to light energy captured by the photosystem’s chlorophyll-a. These electrons are them funneled to making NADPH from NADP+.
While passing these energized electrons, protons (H+) were taken from outside the thylakoid to its inside. This creates a gradient of H+, more inside than outside. This electrochemical gradient fuels the production of ATP. This happens because of a protein machine called ATP synthase. H+ from inside can return to the outside only by passing through ATP synthase. When H+ pass through ATP synthase, it converts ADP to ATP. This is how light and water create energy for the cell.
One of these processes is the next part of the reaction itself. The two sources of energy fuel the light-independent or dark reaction. The energy breaks down the carbon dioxide molecules and reorganizes the constituents to form a molecule of glucose. The chloroplast then harvests energy by breaking down that glucose, just how mitochondria in animal cells produce energy by breaking down the food they consume. Photosynthesis as a combination of the two reactions can be summarized with this expression:
But if plants can produce ATP through photosynthesis, then why do they need to respire? First, photosynthesis can only happen in the daytime, when there is sun around to provide light. Plants still need energy when there is no light. Second, glucose is important molecule for the cell. It can be broken down or built up to make many other biomolecules like DNA , RNA, proteins, and even fats.
In this manner, we share a deep and indispensable symbiotic relationship with plants. The byproduct, or put more impolitely, the waste product exhaled by plants gives us life, whereas carbon dioxide, the waste product that we exhale, gives plants their life. American biologist and one of my favorite science communicators, Lynn Margulis, called this innocuous act of breathing, spirituality.
However, she believes that “the connection doesn’t stop at the exchange of gases in the atmosphere… The fact that we are connected through space and time shows that life is a unitary phenomenon, no matter how we express the fact.”
Also Read: How Do Plants Excrete?
Akash Peshin is an Electronic Engineer from the University of Mumbai, India and a science writer at ScienceABC. Enamored with science ever since discovering a picture book about Saturn at the age of 7, he believes that what fundamentally fuels this passion is his curiosity and appetite for wonder.
Photosynthesis is the process plants, algae and some bacteria use to turn sunlight, carbon dioxide and water into sugar and oxygen.
Additional resources.
Photosynthesis is the process used by plants, algae and some bacteria to turn sunlight into energy. The process chemically converts carbon dioxide (CO2) and water into food (sugars) and oxygen . The chemical reaction often relies on a pigment called chlorophyll, which gives plants their green color. Photosynthesis is also the reason our planet is blanketed in an oxygen-rich atmosphere.
There are two types of photosynthesis: oxygenic and anoxygenic. They both follow very similar principles, but the former is the most common and is seen in plants, algae and cyanobacteria.
During oxygenic photosynthesis, light energy transfers electrons from water (H2O) taken up by plant roots to CO2 to produce carbohydrates . In this transfer, the CO2 is "reduced," or receives electrons, and the water is "oxidized," or loses electrons. Oxygen is produced along with carbohydrates.
This process creates a balance on Earth, in which the carbon dioxide produced by breathing organisms as they consume oxygen in respiration is converted back into oxygen by plants, algae and bacteria.
Anoxygenic photosynthesis, meanwhile, uses electron donors that are not water and the process does not generate oxygen, according to "Anoxygenic Photosynthetic Bacteria" by LibreTexts . The process typically occurs in bacteria such as green sulfur bacteria and phototrophic purple bacteria.
Though both types of photosynthesis are complex, multistep affairs, the overall process can be neatly summarized as a chemical equation.
The oxygenic photosynthesis equation is:
6CO2 + 12H2O + Light Energy → C6H12O6 + 6O2 + 6H2O
Here, six molecules of carbon dioxide (CO2) combine with 12 molecules of water (H2O) using light energy. The end result is the formation of a single carbohydrate molecule (C6H12O6, or glucose) along with six molecules each of oxygen and water.
Similarly, the various anoxygenic photosynthesis reactions can be represented as a single generalized formula:
CO2 + 2H2A + Light Energy → [CH2O] + 2A + H2O
The letter A in the equation is a variable, and H2A represents the potential electron donor. For example, "A" may represent sulfur in the electron donor hydrogen sulfide (H2S), according to medical and life sciences news site News Medical Life Sciences .
Plants absorb CO2 from the surrounding air and release water and oxygen via microscopic pores on their leaves called stomata.
When stomata open, they let in CO2; however, while open, the stomata release oxygen and let water vapor escape. Stomata close to prevent water loss, but that means the plant can no longer gain CO2 for photosynthesis. This tradeoff between CO2 gain and water loss is a particular problem for plants growing in hot, dry environments.
Plants contain special pigments that absorb the light energy needed for photosynthesis.
Chlorophyll is the primary pigment used for photosynthesis and gives plants their green color, according to science education site Nature Education . Chlorophyll absorbs red and blue light and reflects green light. Chlorophyll is a large molecule and takes a lot of resources to make; as such, it breaks down towards the end of the leaf's life, and most of the pigment's nitrogen (one of the building blocks of chlorophyll) is resorbed back into the plant, When leaves lose their chlorophyll in the fall, other leaf pigments such as carotenoids and anthocyanins begin to show. While carotenoids primarily absorb blue light and reflect yellow, anthocyanins absorb blue-green light and reflect red light, according to Harvard University's The Harvard Forest .
Related: What if humans had photosynthetic skin?
Pigment molecules are associated with proteins, which allow them the flexibility to move toward light and toward one another. A large collection of 100 to 5,000 pigment molecules constitutes an "antenna," according to an article by Wim Vermaas , a professor at Arizona State University. These structures effectively capture light energy from the sun, in the form of photons.
The situation is a little different for bacteria. While cyanobacteria contain chlorophyll, other bacteria, for example, purple bacteria and green sulfur bacteria, contain bacteriochlorophyll to absorb light for anoxygenic photosynthesis, according to " Microbiology for Dummies " (For Dummies, 2019).
It was previously hypothesized that just a small number of photons would be needed to kickstart photosynthesis, but researchers never successfully observed this first step. However, in 2023, scientists discovered that photosynthesis appears to begin with a single photon.
The researchers set up an experiment where a photon source spat out two photons at a time. One was absorbed by a detector, while the other hit a bacteria's chloroplast equivalent. When the second photon hit, photosynthesis began.
After performing the test over 1.5 million times, the researchers confirmed that just one photon is needed to start photosynthesis.
Photosynthesis occurs in chloroplasts, a type of plastid (an organelle with a membrane) that contains chlorophyll and is primarily found in plant leaves.
Chloroplasts are similar to mitochondria , the energy powerhouses of cells, in that they have their own genome, or collection of genes, contained within circular DNA. These genes encode proteins that are essential to the organelle and to photosynthesis.
Inside chloroplasts are plate-shaped structures called thylakoids that are responsible for harvesting photons of light for photosynthesis, according to the biology terminology website Biology Online . The thylakoids are stacked on top of each other in columns known as grana. In between the grana is the stroma — a fluid containing enzymes, molecules and ions, where sugar formation takes place.
Ultimately, light energy must be transferred to a pigment-protein complex that can convert it to chemical energy, in the form of electrons. In plants, light energy is transferred to chlorophyll pigments. The conversion to chemical energy is accomplished when a chlorophyll pigment expels an electron, which can then move on to an appropriate recipient.
The pigments and proteins that convert light energy to chemical energy and begin the process of electron transfer are known as reaction centers.
When a photon of light hits the reaction center, a pigment molecule such as chlorophyll releases an electron.
The released electron escapes through a series of protein complexes linked together, known as an electron transport chain. As it moves through the chain, it generates the energy to produce ATP (adenosine triphosphate, a source of chemical energy for cells) and NADPH — both of which are required in the next stage of photosynthesis in the Calvin cycle. The "electron hole" in the original chlorophyll pigment is filled by taking an electron from water. This splitting of water molecules releases oxygen into the atmosphere.
The Calvin cycle is the three-step process that generates sugars for the plant, and is named after Melvin Calvin , the Nobel Prize -winning scientist who discovered it decades ago. The Calvin cycle uses the ATP and NADPH produced in chlorophyll to generate carbohydrates. It takes plate in the plant stroma, the inner space in chloroplasts.
In the first step of this cycle, called carbon fixation, an enzyme called RuBP carboxylase/oxygenase, also known as rubiso, helps incorporate CO2 into an organic molecule called 3-phosphoglyceric acid (3-PGA). In the process, it breaks off a phosphate group on six ATP molecules to convert them to ADP, releasing energy in the process, according to LibreTexts.
In the second step, 3-PGA is reduced, meaning it takes electrons from six NADPH molecules and produces two glyceraldehyde 3-phosphate (G3P) molecules.
One of these G3P molecules leaves the Calvin cycle to do other things in the plant. The remaining G3P molecules go into the third step, which is regenerating rubisco. In between these steps, the plant produces glucose, or sugar.
Three CO2 molecules are needed to produce six G3P molecules, and it takes six turns around the Calvin cycle to make one molecule of carbohydrate, according to educational website Khan Academy.
There are three main types of photosynthetic pathways: C3, C4 and CAM. They all produce sugars from CO2 using the Calvin cycle, but each pathway is slightly different.
Most plants use C3 photosynthesis, according to the photosynthesis research project Realizing Increased Photosynthetic Efficiency (RIPE) . C3 plants include cereals (wheat and rice), cotton, potatoes and soybeans. This process is named for the three-carbon compound 3-PGA that it uses during the Calvin cycle.
Plants such as maize and sugarcane use C4 photosynthesis. This process uses a four-carbon compound intermediate (called oxaloacetate) which is converted to malate , according to Biology Online. Malate is then transported into the bundle sheath where it breaks down and releases CO2, which is then fixed by rubisco and made into sugars in the Calvin cycle (just like C3 photosynthesis). C4 plants are better adapted to hot, dry environments and can continue to fix carbon even when their stomata are closed (as they have a clever storage solution), according to Biology Online.
Crassulacean acid metabolism (CAM) is found in plants adapted to very hot and dry environments, such as cacti and pineapples, according to the Khan Academy. When stomata open to take in CO2, they risk losing water to the external environment. Because of this, plants in very arid and hot environments have adapted. One adaptation is CAM, whereby plants open stomata at night (when temperatures are lower and water loss is less of a risk). According to the Khan Academy, CO2 enters the plants via the stomata and is fixed into oxaloacetate and converted into malate or another organic acid (like in the C4 pathway). The CO2 is then available for light-dependent reactions in the daytime, and stomata close, reducing the risk of water loss.
Discover more facts about photosynthesis with the educational science website sciencing.com . Explore how leaf structure affects photosynthesis with The University of Arizona . Learn about the different ways photosynthesis can be measured with the educational science website Science & Plants for Schools .
This article was updated by Live Science managing editor Tia Ghose on Nov. 3, 2022.
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Daisy Dobrijevic joined Space.com in February 2022 as a reference writer having previously worked for our sister publication All About Space magazine as a staff writer. Before joining us, Daisy completed an editorial internship with the BBC Sky at Night Magazine and worked at the National Space Centre in Leicester, U.K., where she enjoyed communicating space science to the public. In 2021, Daisy completed a PhD in plant physiology and also holds a Master's in Environmental Science, she is currently based in Nottingham, U.K.
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“Photosynthesis is the process used by green plants and a few organisms that use sunlight, carbon dioxide and water to prepare their food.”
The process of photosynthesis is used by plants, algae and certain bacteria that convert light energy into chemical energy. The glucose formed during the process of photosynthesis provides two important resources to organisms: energy and fixed carbon.
Read on to explore what is photosynthesis and the processes associated with it.
Photosynthesis takes place in special organelles known as chloroplast. This organelle has its own DNA, genes and hence can synthesize its own proteins. Chloroplasts consist of stroma, fluid, and stack of thylakoids known as grana. There are three important pigments present in the chloroplast that absorb light energy, chlorophyll a, chlorophyll b, and carotenoids.
Also Read: Photosynthesis Process
There are two different types of photosynthesis:
Oxygenic photosynthesis is more common in plants, algae and cyanobacteria. During this process, electrons are transferred from water to carbon dioxide by light energy, to produce energy. During this transfer of electrons, carbon dioxide is reduced while water is oxidized, and oxygen is produced along with carbohydrates.
During this process, plants take in carbon dioxide and expel oxygen into the atmosphere.
This process can be represented by the equation:
6CO2+ 12H2O + LIGHT ENERGY → C6H12O6 + 6O2 + 6H2O
This type of photosynthesis is usually seen in certain bacteria, such as green sulphur bacteria and purple bacteria which dwell in various aquatic habitats. Oxygen is not produced during the process.
The anoxygenic photosynthesis can be represented by the equation:
CO2 + 2H2A + LIGHT ENERGY → [CH2O] + 2A + H2O
Also Read: Difference between Photosynthesis and Respiration
The photosynthesis apparatus includes the following essential components:
Pigments not only provide colour to the photosynthetic organisms, but are also responsible for trapping sunlight. The important pigments associated with photosynthesis include:
Plastids are organelles found in the cytoplasm of eukaryotic photosynthetic organisms. They contain pigments and can also store nutrients. Plastids are of three types:
Antennae is the collection of 100 to 5000 pigment molecules that capture light energy from the sun in the form of photons. The light energy is transferred to a pigment-protein complex that converts light energy to chemical energy.
The pigment-protein complex responsible for the conversion of light energy to chemical energy forms the reaction centre.
Also Read: Photosynthesis
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Microbe Notes
Photosynthesis is defined as the process, utilized by green plants and photosynthetic bacteria, where electromagnetic radiation is converted into chemical energy and uses light energy to convert carbon dioxide and water into carbohydrates and oxygen.
Table of Contents
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Oxygenic Photosynthesis
The overall reaction of photosynthesis in plants is as follows:
Carbon dioxide + Water + solar energy → Glucose + Oxygen
6CO 2 + 6H 2 O + solar energy → C 6 H 12 O 6 + 6O 2
Carbon dioxide + Water + solar energy → Glucose + Oxygen + Water
6CO 2 + 12H 2 O+ solar energy → C 6 H 12 O 6 + 6O 2 + 6H 2 O
Anoxygenic Photosynthesis
The overall reaction of photosynthesis in sulfur bacteria is as follows:
CO 2 + 2H 2 S + light energy → (CH 2 O) + H 2 O + 2S
Image Source: Simply Science .
Blackman formulated the Law of limiting factors while studying the factors affecting the rate of photosynthesis. This Law states that the rate of a physiological process will be limited by the factor which is in the shortest supply. In the same way, the rate of photosynthesis is also affected by a number of factors, which are namely;
The overall process of photosynthesis can be objectively divided into four steps/ process:
Figure: Photosynthesis takes place in two stages: light-dependent reactions and the Calvin cycle. Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH. The Calvin cycle, which takes place in the stroma, uses energy derived from these compounds to make GA3P from CO 2 . Image Source: OpenStax (Rice University) .
Photosynthesis is divided into two stages based on the utilization of light energy:
Figure: Light-dependent reactions of photosynthesis in the thylakoid membrane of plant cells. Image Source: Wikipedia (Somepics) .
2 H 2 O + 2 NADP + + 3 ADP + 3 P i + light → 2 NADPH + 2 H + + 3 ATP + O 2
Light independent reactions of photosynthesis are anabolic reactions that lead to the formation of a sex-carbon compound, glucose in plants. The reactions in this stage are also termed dark reactions as they are not directly dependent on the light energy but do require the products formed from the light reactions.
Figure: Overview of the Calvin cycle pathway. Image Source: Wikipedia (Mike Jones) .
This stage consists of 3 further steps that lead to carbon fixation/ assimilation.
3 CO 2 + 9 ATP + 6 NADPH + 6 H + → glyceraldehyde-3-phosphate (G3P) + 9 ADP + 8 P i + 6 NADP + + 3 H 2 O
A G3P molecule contains three fixed carbon atoms, so it takes two G3Ps to build a six-carbon glucose molecule. It would take six turns of the cycle to produce one molecule of glucose.
The outcomes of light-dependent reactions of photosynthesis are:
The products of light-independent reactions (Calvin cycle) of photosynthesis are:
The overall products of photosynthesis are:
Photosynthesis in green plants or oxygenic bacteria.
Artificial photosynthesis is a chemical process that mimics the biological process of utilization of sunlight, water and carbon dioxide to produce oxygen and carbohydrates.
Image Source: Phys .
Image Source: Khan Academy .
Photosynthesis takes place in green plants, algae, and some photosynthetic bacteria. | takes place in all living organisms. |
The process of photosynthesis occurs in the thylakoids of chloroplasts. | The process of cellular respiration occurs in mitochondria. |
The reactants of photosynthesis are light energy, carbon dioxide, and water. 6CO + 6H O → C H O + 6O | The reactants of cellular respiration are glucose and oxygen. 6O + C H O → 6CO + 6H O |
The products of photosynthesis are glucose and oxygen. | The products of cellular respiration are carbon dioxide and water. |
Photosynthesis is an anabolic process, resulting in the production of organic molecules. | Cellular respiration is a catabolic process, resulting in the oxidation of organic molecules to release energy. |
Photosynthesis is an endergonic reaction that results in the utilization of energy. | Cellular respiration is an exergonic reaction that results in the release of energy |
Photosynthesis can only take place in the presence of sunlight. | Cellular respiration occurs all the time as it doesn’t require sunlight. |
Where does photosynthesis occur? Photosynthesis occurs in the thylakoid membrane of the chloroplasts.
What are the products of photosynthesis? The products of photosynthesis are carbohydrates (glucose), oxygen, and water molecules.
What are the reactants of photosynthesis? The reactants of photosynthesis are carbon dioxide, water, photosynthetic pigments, and sunlight.
How are photosynthesis and cellular respiration related? Photosynthesis and cellular respiration are essentially the reverses of one another where photosynthesis is an anabolic process resulting in the formation of organic molecules. In contrast, cellular respiration is a catabolic process resulting in the breaking down of organic molecules to release energy.
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Anupama Sapkota
How can we say that 6 calvin cycles are needed to produce 1 glucose molecule why not 2?
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Photosynthesis is a vital biological process through which green plants, algae, and certain bacteria convert light energy into chemical energy. Using sunlight, these organisms transform carbon dioxide and water into glucose and oxygen, substances crucial for their growth and the sustenance of life on Earth. This process not only fuels the organisms themselves but also supports life on the planet by providing oxygen and forming the base of the food chain. Understanding photosynthesis is essential for comprehending how life thrives on Earth, influencing fields ranging from agriculture to energy production.
Photosynthesis is a fundamental biological process through which green plants, algae, and certain bacteria convert light energy into chemical energy. This transformation occurs primarily in the chloroplasts of plant cells where chlorophyll, the pigment responsible for the green color of plants, captures sunlight. The captured light energy is then used to synthesize glucose from carbon dioxide (CO2) and water (H2O), releasing oxygen (O2) as a byproduct. This process not only fuels the plant’s own cellular activities but also provides the base of the food chain for other organisms.
Photosynthesis primarily occurs in the leaves of plants, although it can also take place in any parts of a plant that contain green pigments, typically in the stems and young branches. The leaves are the main site of photosynthesis due to their structure and accessibility to sunlight.
Photosynthesis stands as a crucial biological process through which plants, algae, and certain bacteria convert sunlight into chemical energy, fueling their activities and growth. This process not only supports the organisms performing it but also sustains life on Earth by producing oxygen and forming the basis of the food chain.
Photosynthesis occurs primarily in two stages: the light-dependent reactions and the light-independent reactions (Calvin cycle).
These reactions take place in the thylakoid membranes of the chloroplasts. Here, sunlight drives the process, initiating the flow of electrons through a series of proteins known as the electron transport chain. Plants absorb sunlight using pigment molecules, with chlorophyll being the most prominent. This absorption energizes electrons, which the chloroplasts then use to convert water (H₂O) into oxygen (O₂). As a result, this stage releases oxygen as a byproduct and generates ATP and NADPH, energy carriers that the next stage of photosynthesis uses.
Within the chloroplasts, thylakoid membranes house the light-dependent reactions. These membranes are rich in pigments like chlorophyll that capture light energy, crucial for water photolysis and energy molecule production.
The light-dependent reactions are vital as they provide the necessary energy carriers (ATP and NADPH) for the Calvin cycle. They also maintain the oxygen level in the atmosphere, which is critical for the survival of aerobic life on Earth.
The Calvin cycle unfolds in the stroma, the fluid-filled space surrounding the thylakoid membranes. It does not require light directly. Instead, it uses the ATP and NADPH from the light-dependent reactions to convert carbon dioxide (CO₂) from the air into organic molecules. During this cycle, the enzyme RuBisCO incorporates CO₂ into an organic molecule, starting a series of chemical reactions that regenerate the starting molecule with the production of glucose and other carbohydrates.
The Calvin Cycle is crucial for synthesizing glucose, which plants use as an energy source to fuel various cellular activities and growth. The glucose also serves as a building block for other essential biomolecules such as cellulose and starch. Additionally, this cycle plays a pivotal role in the global carbon cycle, as it is the primary pathway through which atmospheric carbon dioxide transforms into organic compounds within plants.
Photosynthesis is vital for life on Earth. It provides the primary energy source for all ecosystems, where plants form the base of the food web and create biomass from inorganic substances. Moreover, photosynthesis is responsible for the oxygen that makes up a significant portion of the Earth’s atmosphere and supports aerobic life forms.
The formula for photosynthesis is central to understanding how plants convert solar energy into chemical energy. Here is the equation:
6𝐶𝑂2+6𝐻2𝑂+𝑙𝑖𝑔ℎ𝑡𝑒𝑛𝑒𝑟𝑔𝑦→𝐶6𝐻12𝑂6+6𝑂26 CO 2+6 H 2 O + lightenergy → C 6 H 12 O 6+6 O 2
This equation represents the overall process by which plants, algae, and certain bacteria produce glucose and oxygen from carbon dioxide and water, using energy from sunlight. Here’s a breakdown of each component:
Tiny pores in the leaves called stomata take carbon dioxide from the air. Carbon dioxide is one of the key reactants in the process.
The roots absorb water and transport it to the leaves, providing the source of electrons and protons necessary for the chemical reactions of photosynthesis. Water molecules split to produce oxygen.
Chlorophyll and other pigments in the chloroplasts capture light energy, converting it into chemical energy in the form of ATP and NADPH. These energy carriers then power the later stages of photosynthesis.
The plant uses the sugar produced by photosynthesis as an energy source. It can use this sugar immediately, store it, or convert it into other necessary substances for growth.
Oxygen releases through the stomata as a byproduct, playing a critical role in the Earth’s atmosphere and supporting the survival of aerobic organisms.
Light energy, especially from the sun, triggers photosynthesis. Pigments in the plant, mainly chlorophyll, absorb mostly blue and red wavelengths of light, crucial for converting ADP and inorganic phosphate into ATP, and NADP+ into NADPH, which are used in glucose synthesis.
Chlorophyll primarily absorbs light. Other pigments like carotenoids and phycobilins help capture energy from sunlight, absorbing light wavelengths that chlorophyll cannot. These pigments are critical in harnessing the light energy required to drive the reactions of photosynthesis.
Water acts as an electron donor in the light-dependent reactions of photosynthesis. The process of photolysis splits water molecules, releasing electrons, hydrogen ions, and oxygen. The reactions use the electrons and hydrogen ions to produce glucose, while plants release oxygen as a byproduct.
The stomata in the leaves absorb CO2 from the atmosphere. It is a critical substrate in the Calvin cycle (light-independent reactions), where it fixes into glucose using the ATP and NADPH produced in the light-dependent reactions.
Various enzymes facilitate the chemical reactions involved in photosynthesis. For example, the enzyme Rubisco plays a pivotal role in fixing carbon dioxide during the Calvin cycle, converting it into glucose. Enzymes ensure that the photosynthetic reactions occur efficiently and at a sufficient rate to meet the plant’s needs.
Chloroplasts, specialized organelles in plant and algal cells, house the biochemical machinery necessary for photosynthesis. The thylakoid membranes in chloroplasts provide a framework for light-dependent reactions, while the surrounding stroma hosts the Calvin cycle.
Temperature and pH levels also influence the rate of photosynthesis. The enzymatic reactions involved are sensitive to temperature and have optimal pH ranges. Deviations from these optimal conditions can slow down or inhibit the process.
Photosynthesis, a critical process through which green plants, algae, and some bacteria convert light energy into chemical energy, occurs largely in specialized cells and organelles designed to maximize the efficiency of light capture and conversion. The primary cells and organelles involved in photosynthesis are mesophyll cells, chloroplasts, and, more specifically, structures within the chloroplasts including the thylakoid membranes and stroma.
Mesophyll cells in plant leaves primarily conduct photosynthesis. These cells contain high concentrations of chloroplasts, the essential organelles where photosynthesis takes place. There are two types of mesophyll cells:
These cells, located directly under the leaf surface, are elongated and densely packed with chloroplasts, primarily absorbing light and conducting photosynthesis.
These cells, found below the palisade mesophyll, aid in gas exchange and also contain chloroplasts contributing to photosynthesis.
Chloroplasts are the key organelles where photosynthesis occurs. These double-membraned structures contain their own DNA and can replicate independently within the cell. Inside chloroplasts, two major stages of photosynthesis—the light-dependent reactions and the Calvin cycle—take place in different components:
These membrane-bound structures, stacked into grana within chloroplasts, contain chlorophyll, essential for absorbing sunlight. The light-dependent reactions of photosynthesis occur here, converting sunlight into chemical energy in the form of ATP and NADPH.
This fluid-filled space surrounds the thylakoid membranes inside the chloroplast. Here, the Calvin cycle, also known as the light-independent reactions, occurs. It uses the ATP and NADPH produced by the light-dependent reactions to convert carbon dioxide into glucose, serving as an energy storage molecule for the plant.
Each part within the mesophyll cells and chloroplasts plays a crucial role in the process of photosynthesis:
1. light intensity.
Measuring energy efficiency.
The energy efficiency of photosynthesis generally refers to the percentage of solar energy that plants convert into the chemical energy of sugars. Solar energy strikes the Earth with a power of about 1000 watts per square meter at noon on a clear day. Plants absorb only a fraction of this energy, primarily using the visible light spectrum.
Several factors impact the energy efficiency of photosynthesis:
Despite its relatively low energy efficiency, photosynthesis is incredibly effective in supporting life on Earth:
Scientists are researching ways to enhance the efficiency of photosynthesis to benefit food production and bioenergy. These efforts include genetically modifying plants to absorb light more effectively, bypassing inefficient steps in natural photosynthesis, and developing artificial photosynthesis systems that could one day surpass the efficiency of natural photosynthesis.
C4 photosynthesis is a highly efficient photosynthetic pathway that some plants use to overcome the limitations of the standard C3 pathway, especially under conditions of drought, high temperatures, and limited nitrogen or CO2. In C4 photosynthesis, plants capture CO2 in the mesophyll cells and then transport it to the bundle-sheath cells where the Calvin cycle occurs. This process minimizes photorespiration, an energy-wasting process that occurs in C3 plants. Key enzymes like PEP carboxylase initially fix CO2 into a four-carbon compound, which is why we call it C4 photosynthesis. This adaptation allows C4 plants, such as maize and sugarcane, to photosynthesize more efficiently under extreme conditions compared to C3 plants.
Photosynthesis is the process where plants use sunlight to produce energy from water and carbon dioxide, releasing oxygen.
Photosynthesis transforms sunlight into chemical energy, enabling plants to create glucose and oxygen from water and CO2.
The main process of photosynthesis involves converting light energy into chemical energy, which plants use to make glucose and release oxygen.
Photosynthesis begins when chlorophyll in plant cells absorbs sunlight, initiating energy conversion that powers chemical reactions.
Photosynthesis is the process by which plants make their own food using sunlight, water, and carbon dioxide.
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Scientists first began to study and understand photosynthesis in the 1770s.
Photosynthesis is a process by which plants, algae, and certain microorganisms transform light energy from the sun into the chemical energy of food. During photosynthesis, energy from sunlight is harnessed and used to convert carbon dioxide and water into organic compounds—namely sugar molecules—and oxygen. The process enables photosynthetic organisms to change light energy into a form of energy—the chemical energy in sugars—that their cells can store and use to grow and thrive. This chemical energy is transferred to animals that eat plants as well as other photosynthetic organisms, and to the animals that eat other animals ( see food chain ). The oxygen produced through photosynthesis is released into the atmosphere (in the case of aquatic organisms, into the aquatic environment) and used by organisms for cellular respiration .
The importance of photosynthesis to life on Earth cannot be overstated. Photosynthesis directly and indirectly supplies the food we eat and the air we breathe. Without it, the Earth’s fundamental food supply would not be replenished. With less food available, most organisms would disappear, and the planet would become devoid of oxygen. ( See also ecosystem .)
An overview of photosynthesis is presented in the section that follows. For a detailed review of the chemical reactions in photosynthesis, see Photosynthesis in Detail in this article.
Photosynthesis is a chemical process in which light energy from the sun drives a series of chemical reactions between carbon dioxide and water, forming glucose (a simple sugar) and oxygen as end products. The overall process can be expressed as follows:
carbon dioxide + water + light energy → glucose + oxygen
The reaction requires chlorophyll, a green pigment found in all organisms that can undergo photosynthesis. Chlorophyll plays a critical role in capturing energy from incoming sunlight and transferring it to the chemical compounds involved in photosynthesis. The chlorophyll in plant cells is contained in organelles called chloroplasts. All photosynthesis in plants takes place within the chloroplasts, which are concentrated in the palisade cells of leaves.
Photosynthesis proceeds through a series of steps. Water enters the plant through the roots and travels up to the leaves. Carbon dioxide enters the leaves through tiny pores called stomata ( see plant ). Inside the chloroplasts, chlorophyll captures energy from sunlight; this energy then drives a series of chemical reactions between carbon dioxide and water, changing them into glucose and oxygen.
The oxygen produced in photosynthesis is released into the air as a waste product. The plant may burn some of the glucose immediately for energy to power cellular activities ( see cellular respiration ). Some glucose molecules may be converted to other sugars, such as fructose or sucrose, or linked together to form cellulose —a large complex carbohydrate needed to build and repair cell walls. Most of the glucose produced in photosynthesis is linked together to form starch , a large complex carbohydrate. Plants store starch in their tissues and break it down into glucose molecules when they need energy.
In photosynthesis, light energy reacts with six molecules of carbon dioxide (CO 2 ) and six molecules of water (H 2 O) to produce one molecule of glucose (C 6 H 12 O 6 ) and six molecules of oxygen (O 2 ). The chemical equation for photosynthesis is as follows:
6CO 2 + 6H 2 O + light → C 6 H 12 O 6 + 6O 2
The actual process, however, is far more complex than the equation might suggest. The equation indicates that atmospheric carbon dioxide, CO 2 , is “fixed,” or converted from a gas to the solid sugar glucose (C 6 H 12 O 6 ), water (H 2 O) is consumed, and oxygen (O 2 ) is liberated. Yet this seemingly simple reaction consists of two distinctly different processes. The first is photochemical and the second is biochemical; they are the so-called light and dark, or light-independent, reactions. The rate of these reactions is controlled by various regulatory enzymes as well as by environmental conditions such as light intensity, temperature, and the availability of carbon dioxide, water, and certain minerals.
All photosynthetic organisms—with the exception of a small group of bacteria—contain various forms of the green pigment chlorophyll, which is critical in the transfer of energy from light to chemical compounds. Other pigments may also be involved, depending on the type of organism undergoing photosynthesis. Light for photosynthesis is harvested from the visible spectrum ( see color ; light ), and different pigments absorb the light from a particular range within that spectrum. The result is a form of light-absorption array, or antenna, that neatly matches the entire visible spectrum.
During the light reaction, incoming light energy is absorbed, or captured, by chlorophyll pigments in the cell. Each photon, or “particle” of light, then undergoes a process called free-charge separation. In this process an electron (e – ) is separated from the chlorophyll molecule and is passed, at a higher energy, to a carrier molecule, thereby converting the energy of the photon into chemical energy. The electrons lost by the chlorophyll molecules are replaced by electrons that split off from water. This process, called photolysis, forms oxygen as a waste product. The photolytic reaction can be described as follows:
H 2 O → 2H + + 2e – + 1 / 2 O 2
Two such free-charge separations, called photoacts, are connected in series. As electrons pass between photoacts, the energy-rich compound adenosine triphosphate (ATP) is formed by the addition of an inorganic phosphate group (P i ) to a molecule of adenosine diphosphate (ADP), and the electron loses energy. This process is called photophosphorylation, and it can be described as follows:
ADP + P i → ATP + H 2 O
In the second photoact, the electron-acceptor compound nicotinamide adenine dinucleotide phosphate (NADP + ) is reduced—that is, it gains electrons—to form the electron donor compound NADPH:
NADP + + H + + 2e – → NADPH
The compounds ATP and NADPH are used in the next stage of photosynthesis, the dark, or light-independent, reaction. In nature, for every ten photons absorbed, two to three molecules of ATP and two molecules of NADPH are formed. This translates into an energy conversion efficiency of about 38 percent.
In the dark reaction of photosynthesis, the ATP and NADPH formed in the light reaction are used to transform inorganic carbon dioxide (CO 2 ) into organic carbon compounds, a process called carbon fixation. The term dark reaction is misleading because the process can take place in both light and darkness. For that reason, many people refer to this process as “light independent” rather than “dark.”
Carbon fixation takes place as a series of steps in a complex biochemical cycle known as the Calvin-Benson cycle. This process produces intermediate sugar phosphate compounds that are then used to synthesize glucose. The process begins with three molecules of carbon dioxide (CO 2 ) and produces a net output of one molecule of a 3-carbon sugar phosphate called glyceraldehyde-3-phosphate (Gal3P). The process requires energy from nine molecules of ATP and electrons from six molecules of NADPH. The overall process can be summarized as follows:
3 CO 2 + 9 ATP + 6 NADPH → Gal3P + 6 NADP + + 9 ADP + 8 P i
The cycle begins with the reaction of the 5-carbon sugar ribulose bisphosphate (RuBP) with carbon dioxide (CO2), producing the intermediate 3-carbon molecule phosphoglycerate (PGA). The reaction is brought about, or catalyzed, by the enzyme ribulose bisphosphate carboxylase/oxygenase (RuBisCO):
3 CO 2 + 3 RuBP → 6 PGA
Each PGA molecule undergoes phosphorylation, gaining a phosphate group from ATP, and is reduced with NADPH, thereby gaining an electron. These reactions ultimately produce six molecules of glyceraldehyde-3-phosphate:
6 PGA + 6 ATP + 6 NADPH → 6 Gal3P
Five molecules of Gal3P are converted to form three molecules of the 5-carbon RuBP. The process requires energy from 3 ATP:
5 Gal3P + 3 ATP → 3 RuBP + 3 ADP
The RuBP molecules reenter the cycle, ready to react with new molecules of carbon dioxide.
The remaining molecule of the 3-carbon Gal3P can combine with another to form the 6-carbon sugar glucose:
2 Gal3P → C 6 H 12 O 6
The glucose can then be converted to other sugars, such as fructose or sucrose, or it can be linked to form complex carbohydrates, such as starch or cellulose. Glucose can also be used in other synthetic reactions to form fats or proteins as needed by the plant. ( See also carbohydrate ; plant .)
Begun in the 19th century, the investigation of the mechanism of photosynthesis is still continuing today. A continuing area of research since the 1970s has involved the use of genetic engineering to alter specific photosynthetic mechanisms and improve crop productivity. However, the complex factors in agriculture and in the genetic manipulation of crops have frustrated scientists; by the early 21st century, genetic engineering had not yet been shown to improve crop yields.
An interesting area of research has been the discovery that certain animals are capable of converting light energy into chemical energy on a small scale. For example, the emerald green sea slug (Elysis chlorotica) acquires chloroplasts from the algae it eats. When the slug accumulates enough chloroplasts, it can undergo photosynthesis and no longer needs to ingest food.
Joseph S. Ramus
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photosynthesis
Did you know.
Photosynthesis Has Greek Roots
The Greek roots of photosynthesis combine to produce the basic meaning "to put together with the help of light". Photosynthesis is what first produced oxygen in the atmosphere billions of years ago, and it's still what keeps it there. Sunlight splits the water molecules (made of hydrogen and oxygen) held in a plant's leaves and releases the oxygen in them into the air. The leftover hydrogen combines with carbon dioxide to produce carbohydrates, which the plant uses as food—as do any animals or humans who might eat the plant.
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'photosynthesis.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
1898, in the meaning defined above
photosynthate
photosynthetic ratio
“Photosynthesis.” Merriam-Webster.com Dictionary , Merriam-Webster, https://www.merriam-webster.com/dictionary/photosynthesis. Accessed 29 Jun. 2024.
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Photosynthesis for kids - learn all about photosynthesis, what is photosynthesis.
Photosynthesis = “Photo” + “Synthesis”. “Photo” which means light, “Synthesis” which means putting together.
Just think, plants cannot move, but they need food to survive and grow. But how do they manage their food or who helps them?
The answer is, plants are the most independent living thing on earth. They make their own food without any help from people.
Plants use sunlight, water, CO2 ( carbon dioxide i.e. present in air) to make their food. And this process of making food is called. photosynthesis . Now we will explore more about photosynthesis for kids.
Let’s explore how photosynthesis works step by step. For photosynthesis, plants need 3 essential things. Water and Minerals CO2 (Carbon Dioxide) Sunlight Step 1 -The root of the plant takes water and minerals from the soil . There are veins in the plant named Xylem , transport water and minerals to the whole plant, including its leaves.
The leaves are the food factory of the plant. Because the photosynthesis process takes place in the leaves of plants. So, every necessary thing needs to reach the leaves to make food .
Step 2 – Carbon dioxide (CO2) from the air enters through tiny pores (holes) in the leaves. These pores are called stomata.
We can say that plants also breathe like us through stomata. The only difference is, we breathe in oxygen and breathe out carbon dioxide but plants breathe in carbon dioxide and breathe out oxygen. What a fantastic understanding between us and plants!!
Step 3 – The leaves are basically made of tiny cells . If we see the structure of Plant Cells , we will find that inside these cells there is a small part called chloroplasts . Each chloroplast contains a green substance called Chlorophyll , which actually absorbs energy from sunlight.
Did you know? Chlorophyll is the substance that gives leaves their green color.
Let’s understand what happens during photosynthesis step by step.
The plant needs to make Glucose or Food. For that they need two ingredients; Hydrogen and Carbon dioxide .
FACT #1. The energy for photosynthesis comes from light.
FACT #2. During photosynthesis, plants use sunlight, water, carbon dioxide to make their food.
FACT #3. Light energy is converted to chemical energy by chlorophyll.
FACT #4. The green color of leaves is due to chlorophyll.
FACT #5. Leaves change color in autumn because plants slow down the process of photosynthesis
FACT #6. Plants perform photosynthesis in organelles called chloroplasts. There are two parts of chloroplast i.e. grana and stroma
FACT #7. Only plants do not use photosynthesis. Rather some bacteria, such as cyanobacteria, and proteases, such as algae, are also producers. These single-celled organisms also contain chlorophyll.
FACT #8. All living things on this planet depend on organic molecules synthesized by plants as a result of photosynthesis.
I hope you understand the topic of photosynthesis for kids. Don’t forget to attempt a photosynthesis quiz for kids to check your knowledge. V isit here to know more about photosynthesis for kids.
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photosynthesis
[ foh-t uh - sin -th uh -sis ]
/ ˌfəʊtəʊsɪnˈθɛtɪk; ˌfəʊtəʊˈsɪnθɪsɪs /
/ fō′tō-sĭn ′ thĭ-sĭs /
Derived forms.
Origin of photosynthesis 1
Compare meanings.
How does photosynthesis compare to similar and commonly confused words? Explore the most common comparisons:
Specifically, he was interested in the protein-based "reaction centers" in spinach leaves that are the basic mechanism for photosynthesis—the chemical process by which plants convert carbon dioxide into oxygen and carbohydrates.
Algae and plants use photosynthesis to turn sunlight into food.
According to the Washington Post, this happens because as the days shorten and turn frigid, it’s not worth it for some trees to expend energy to conduct photosynthesis.
In a steady state, most of the energy captured by photosynthesis is used up by the furnace of respiration and metabolism burning on Earth’s surface by its infrared layer of life.
There’s no sunlight beneath half a mile of ice, so of course there’s no photosynthesis.
Nevertheless, it was required, and at least it was more fun than studying algebra or photosynthesis.
Re-solarizing the food chain should be our goal in every way—taking advantage of the everyday miracle that is photosynthesis.
As the microbes moved toward the light to carry out photosynthesis, they projected the image of the stencil.
Timiriazeff, in his Croonian Lecture, was the first to see the connexion between photosynthesis and the Lagado research.
On the other hand, their ancestors, the green or yellow mastigota, form new plasm by photosynthesis like true cells.
There the miracle of life consists merely of the chemical process of plasmodomism by photosynthesis.
Like von Baeyer's hypothesis, this assumes that formaldehyde and oxygen are the first products of photosynthesis.
In general, starch is the final product of photosynthesis in most green plants; but there are many exceptions to this.
April 28, 2020 By Emma Vanstone Leave a Comment
Green plants make sugar for growth by a process called photosynthesis . Photosynthesis is a process where light energy is converted to chemical energy in the form of sugars. It’s a process that provides the main source of oxygen in the atmosphere and is essential for almost all life on Earth.
Plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of glucose.
The glucose molecules created by photosynthesis act as fuel for cells and are used for cellular respiration and fermentation.
Carbon dioxide + water (and light ) ———> glucose and oxygen
Photosynthesis takes place in chloroplast cells, which contain a substance called chlorophyll. It is chlorophyll, which gives plants their green colour.
Chloroplasts are one of the organelles in a plant cell. We made a jelly model of plant cell to learn about organelles and plant cell structure.
Sunlight is also needed to make chlorophyll. If plants are kept in the dark, they can’t make chlorophyll and will have yellow leaves! You can see this in our multicoloured cress caterpillar .
Four factors affect the rate of photosynthesis . The faster it occurs, the more the plant grows.
Light – the more light there is, the faster photosynthesis occurs.
Water – lack of water slows photosynthesis down.
Temperature – photosynthesis works best at around 30 degrees Celsius.
Carbon dioxide levels – photosynthesis is faster if there is more carbon dioxide in the air.
Plants make the energy to grow through a process called respiration . This uses the sugar produced by photosynthesis and oxygen.
Leaves are green as they contain lots of chlorophyll, which absorbs sunlight.
They are thin and have a large surface area. This means they can absorb a lot of sunlight, and gases such as oxygen and carbon dioxide can pass in and out of the leaf easily.
Leaves have veins – xylem and phloem, which transport water, minerals and sugars around the plant.
Plants, algae, and some types of bacteria use photosynthesis to create energy.
A large percentage of the Earth’s oxygen comes from phytoplankton in the oceans, which contain chlorophyll and use photosynthesis to create energy.
Chlorophyll is a green pigment which absorbs energy from blue and red light waves and reflects green light waves, which is why plants look green!
Chlorophyll in a plant is found in an organelle called a chloroplast. This is where photosynthesis occurs.
Photosynthesis also allows plants to make energy for growth and repair, and it has an important ecological impact.
Plants incorporate the carbon from carbon dioxide into organic molecules ( carbon fixation ). This creates a carbon source for animals who cannot create their own and also removes carbon dioxide from the air, slowing down the rate at which it builds up in the atmosphere.
Photosynthesis also creates oxygen, which is needed for most life on Earth!
Do you have more questions? You might find the answers in my collection of science questions for kids .
Last Updated on January 26, 2024 by Emma Vanstone
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In chemical terms, photosynthesis is a light-energized oxidation-reduction process. (Oxidation refers to the removal of electrons from a molecule; reduction refers to the gain of electrons by a molecule.) In plant photosynthesis, the energy of light is used to drive the oxidation of water (H 2 O), producing oxygen gas (O 2 ), hydrogen ions (H ...
The process. During photosynthesis, plants take in carbon dioxide (CO 2) and water (H 2 O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.
Photosynthesis Equation. 6 CO 2 + 6 H 2 O + Light -> C 6 H 12 O 6 + 6 O 2 + 6 H 2 O. Above is the overall reaction for photosynthesis. Using the energy from light and the hydrogens and electrons from water, the plant combines the carbons found in carbon dioxide into more complex molecules. While a 3-carbon molecule is the direct result of ...
Photosynthesis. Photosynthesis is a process by which phototrophs convert light energy into chemical energy, which is later used to fuel cellular activities. The chemical energy is stored in the form of sugars, which are created from water and carbon dioxide. 3,12,343.
Photosynthesis is the process in which light energy is converted to chemical energy in the form of sugars. In a process driven by light energy, glucose molecules (or other sugars) are constructed from water and carbon dioxide, and oxygen is released as a byproduct. The glucose molecules provide organisms with two crucial resources: energy and ...
Photosynthesis ( / ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [1] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their activities.
Photosynthesis definition: Photosynthesis is a physio-chemical process carried out by photo-auto-lithotrophs. In simpler language, photosynthesis is the process by which green plants convert light energy into 'chemical energy'. ... The simple carbon sugars formed via the C3 cycle are utilized by the biological systems to form complex ...
Stages of the Process. Photosynthesis occurs in two stages: 1) The Light-dependent Reaction. Takes place in the thylakoid membranes of chloroplasts only during the day in the presence of sunlight. High-energy phosphate molecules adenosine triphosphate ( ATP) and the reducing agent NADPH are produced with the help of electron transport chain.
Photosynthesis is how plants and some microorganisms make carbohydrates. It is an endothermic (takes in heat) chemical process which uses sunlight to turn carbon dioxide into sugars. The sugars are used by the cell as energy, and to build other kinds of molecules. Fundamentally, photosynthesis converts light energy into chemical energy.
Photosynthesis is a vital process that converts light energy into chemical energy and organic molecules. In this article, you will learn how different organisms perform photosynthesis, what types of pigments and reactions are involved, and how photosynthesis affects the biosphere. Khan Academy is a free online learning platform that offers courses in various subjects, including biology.
Photosynthesis consists of both light-dependent reactions and light-independent reactions. In plants, the so-called "light" reactions occur within the chloroplast thylakoids, where the ...
Photosynthesis is the process in which green plants use sunlight to make their own food. Photosynthesis is necessary for life on Earth. Without it there would be no green plants, and without green plants there would be no animals. Interactive
Photosynthesis is really important for the plant because it provides the plant with food: some of the glucose is used immediately, to give the plant energy in the process of respiration. some of ...
Photosynthesis is the process used by plants to convert sunlight into chemical energy that can be used to fuel the plants' growth. The process is fueled by the sun and powered by the chloroplasts in the plants' leaves. The process begins with the sun's light energy breaking down water molecules into oxygen and hydrogen.
Photosynthesis is the process used by plants, algae and some bacteria to turn sunlight into energy. The process chemically converts carbon dioxide (CO2) and water into food (sugars) and oxygen ...
photosynthesis: the process by which plants and other photoautotrophs generate carbohydrates and oxygen from carbon dioxide, water, and light energy in chloroplasts. photoautotroph: an organism that can synthesize its own food by using light as a source of energy. chemoautotroph: a simple organism, such as a protozoan, that derives its energy ...
What Is Photosynthesis? "Photosynthesis is the process used by green plants and a few organisms that use sunlight, carbon dioxide and water to prepare their food.". The process of photosynthesis is used by plants, algae and certain bacteria that convert light energy into chemical energy. The glucose formed during the process of ...
Photosynthesis is the primary source of energy in autotrophs where they make their food by utilizing carbon dioxide, sunlight, and photosynthetic pigments. Photosynthesis is equally essential for heterotrophs, as they derive their energy from the autotrophs. Photosynthesis in plants is necessary to maintain the oxygen levels in the atmosphere.
Photosynthesis. Photosynthesis is a vital biological process through which green plants, algae, and certain bacteria convert light energy into chemical energy. Using sunlight, these organisms transform carbon dioxide and water into glucose and oxygen, substances crucial for their growth and the sustenance of life on Earth. This process not only ...
Photosynthesis is a chemical process in which light energy from the sun drives a series of chemical reactions between carbon dioxide and water, forming glucose (a simple sugar) and oxygen as end products. The overall process can be expressed as follows: carbon dioxide + water + light energy → glucose + oxygen. The reaction requires ...
The meaning of PHOTOSYNTHESIS is synthesis of chemical compounds with the aid of radiant energy and especially light; especially : formation of carbohydrates from carbon dioxide and a source of hydrogen (such as water) in the chlorophyll-containing cells (as of green plants) exposed to light. Photosynthesis Has Greek Roots
Photosynthesis means "Photo" (means light) and "Synthesis" (means putting together.) The process of making food by plant is called photosynthesis. During photosynthesis, plants use sunlight, water, CO2 (carbon dioxide i.e. present in air) to make their food. The leaves are the food factory of the plant. Chlorophyll absorbs energy from ...
Photosynthesis definition: the complex process by which carbon dioxide, water, and certain inorganic salts are converted into carbohydrates by green plants, algae, and certain bacteria, using energy from the sun and chlorophyll. . See examples of PHOTOSYNTHESIS used in a sentence.
Photosynthesis is a process where light energy is converted to chemical energy in the form of sugars. It's a process that provides the main source of oxygen in the atmosphere and is essential for almost all life on Earth. Photosynthesis made simple. Plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of ...