Sciencing_Icons_Science SCIENCE

Sciencing_icons_biology biology, sciencing_icons_cells cells, sciencing_icons_molecular molecular, sciencing_icons_microorganisms microorganisms, sciencing_icons_genetics genetics, sciencing_icons_human body human body, sciencing_icons_ecology ecology, sciencing_icons_chemistry chemistry, sciencing_icons_atomic & molecular structure atomic & molecular structure, sciencing_icons_bonds bonds, sciencing_icons_reactions reactions, sciencing_icons_stoichiometry stoichiometry, sciencing_icons_solutions solutions, sciencing_icons_acids & bases acids & bases, sciencing_icons_thermodynamics thermodynamics, sciencing_icons_organic chemistry organic chemistry, sciencing_icons_physics physics, sciencing_icons_fundamentals-physics fundamentals, sciencing_icons_electronics electronics, sciencing_icons_waves waves, sciencing_icons_energy energy, sciencing_icons_fluid fluid, sciencing_icons_astronomy astronomy, sciencing_icons_geology geology, sciencing_icons_fundamentals-geology fundamentals, sciencing_icons_minerals & rocks minerals & rocks, sciencing_icons_earth scructure earth structure, sciencing_icons_fossils fossils, sciencing_icons_natural disasters natural disasters, sciencing_icons_nature nature, sciencing_icons_ecosystems ecosystems, sciencing_icons_environment environment, sciencing_icons_insects insects, sciencing_icons_plants & mushrooms plants & mushrooms, sciencing_icons_animals animals, sciencing_icons_math math, sciencing_icons_arithmetic arithmetic, sciencing_icons_addition & subtraction addition & subtraction, sciencing_icons_multiplication & division multiplication & division, sciencing_icons_decimals decimals, sciencing_icons_fractions fractions, sciencing_icons_conversions conversions, sciencing_icons_algebra algebra, sciencing_icons_working with units working with units, sciencing_icons_equations & expressions equations & expressions, sciencing_icons_ratios & proportions ratios & proportions, sciencing_icons_inequalities inequalities, sciencing_icons_exponents & logarithms exponents & logarithms, sciencing_icons_factorization factorization, sciencing_icons_functions functions, sciencing_icons_linear equations linear equations, sciencing_icons_graphs graphs, sciencing_icons_quadratics quadratics, sciencing_icons_polynomials polynomials, sciencing_icons_geometry geometry, sciencing_icons_fundamentals-geometry fundamentals, sciencing_icons_cartesian cartesian, sciencing_icons_circles circles, sciencing_icons_solids solids, sciencing_icons_trigonometry trigonometry, sciencing_icons_probability-statistics probability & statistics, sciencing_icons_mean-median-mode mean/median/mode, sciencing_icons_independent-dependent variables independent/dependent variables, sciencing_icons_deviation deviation, sciencing_icons_correlation correlation, sciencing_icons_sampling sampling, sciencing_icons_distributions distributions, sciencing_icons_probability probability, sciencing_icons_calculus calculus, sciencing_icons_differentiation-integration differentiation/integration, sciencing_icons_application application, sciencing_icons_projects projects, sciencing_icons_news news.

  • Share Tweet Email Print
  • Home ⋅
  • Science ⋅
  • Biology ⋅
  • Cell (Biology): An Overview of Prokaryotic & Eukaryotic Cells

What Is the End Product of Photosynthesis?

What Is the End Product of Photosynthesis

Describe What a Photosystem Does for Photosynthesis

Humans and most other animals need certain things to survive. Oxygen is one of them, and the carbohydrate glucose is another. Fortunately for them, plants (and certain bacteria and algae) produce both of these as the result of a complex process known as photosynthesis.

The Formula

The formula associated with the process of photosynthesis is

6H 2 O + 6CO 2 = C 6 H 12 O 6 + 6O 2 .

This formula tells you is that six molecules of water plus six molecules of carbon dioxide will produce one molecule of glucose plus six molecules of oxygen. This entire process goes through two distinct stages before it is completed. The first stage is a light-dependent process and the second stage is a light-independent process.

Light Dependent

In the light-dependent process, the electrons of the chloroplasts (special organelles used to carry out photosynthesis) are excited into a higher energy state when they are bombarded with light. These excited electrons cause a series of reactions that produce adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). ATP and NADPH are then used to make carbon bonds in the light-independent process. Water molecules present in the light-dependent process are split. Their oxygen molecules are released into the atmosphere.

Light Independent

Recall the splitting of the water molecules in the light-dependent process that released oxygen molecules into the atmosphere. Since water is H 2 0, there is still a hydrogen atom remaining. This hydrogen atom is used in the light-independent process when plants take carbon dioxide from the atmosphere. The carbon dioxide and hydrogen become bound together through a process called carbon fixation, which forms a non-specific carbohydrate.

Photophosphorylation

Photophosphorylation is the process by which light energy produces NADPH. Special pigments found in the plant’s cells known as chlorophyll make this process possible. The two main types of chlorophyll are chlorophyll A and chlorophyll B. In simple terms, the electrons of water molecules present in chlorophyll B become excited by the presence of light. Chlorophyll B takes one of these excited electrons splitting the H 2 O molecule into H + and O -2 . O -2 is converted into O 2 and released into the atmosphere. The excited electron is attached to a primary electron receptor, and through a series of complex reactions forms NADPH. NADPH is the energy carrier used in carbon fixation.

The Calvin Cycle

Plants produce glucose in a process known as the Calvin cycle. The carbon dioxide captured in the light-independent process is processed in this cycle. For every six molecules of carbon dioxide captured and put into the cycle, one molecule of glucose is produced. The chemical that captures the carbon dioxide for use in the Calvin cycle is ribulose biphosphate.

Related Articles

Phases of photosynthesis & its location, what happens in the light reaction of photosynthesis, organelles involved in photosynthesis, what are the reactants & products in the equation..., how do plant cells obtain energy, how oxygen gas is produced during photosynthesis, how do plants use water in photosynthesis, what is the waste product of photosynthesis, what is reduced & oxidized in photosynthesis, what is the sun's role in photosynthesis, what provides electrons for the light reactions, materials needed for photosynthesis, what is the photosynthesis equation, what are light independent reactions, what are light dependent reactions, how do plants store energy during photosynthesis, chemical ingredients of photosynthesis, difference between aerobic & anaerobic cellular respiration....

  • Royal Society of Chemistry: Photosynthesis
  • YouTube: Khan Academy - Photosynthesis Calvin Cycle
  • YouTube; Khan Academy - 16:58 C-4 Photosynthesis Khan Academy 336K views 21:14 Photosynthesis (updated honors biology) Beverly Biology 53K views 14:37 Photosynthesis: Fun in the Sun ThePenguinProf 115K views 4:54 Science - Amazing Process Of Photosynthesis Designmate Pvt. Ltd. - Official 130K views 15:38 Photosynthesis and Respiration Bozeman Science 711K views 3:09 Learn about photosynthesis learning junction 117K views How to Wake up at 4:30 AM and be Excited - 4 Simple Steps to Wake up Early Primed 4M views Photosynthesis & Respiration pvsciteach 347K views How C3, C4 and CAM Plants Do Photosynthesis BOGObiology 100K views Photosynthesis and the Teeny Tiny Pigment Pancakes Amoeba Sisters 668K views Photosynthesis: Light Reactions and the Calvin Cycle Professor Dave Explains 29K views Introduction to cellular respiration | Cellular respiration | Biology | Khan Academy Khan Academy 2.2M views DNA replication and RNA transcription and translation | Khan Academy Khan Academy 1.3M views Photosynthesis: Comparing C3, C4 and CAM RicochetScience 15K views Overview of glycolysis | Cellular respiration | Biology | Khan Academy Khan Academy 1.8M views Photosynthesis

About the Author

Kelley Boles obtained his B.A. in writing from the University of Central Arkansas in 2005. He has been a freelance writer within his community ever since. His most ambitious project today has been the writing of a comprehensive assembly manual for BBQ smokers manufactured by Royal Oak Enterprises LLC.

Photo Credits

Plant image by Hedgehog from Fotolia.com

Find Your Next Great Science Fair Project! GO

Back Home

  • Science Notes Posts
  • Contact Science Notes
  • Todd Helmenstine Biography
  • Anne Helmenstine Biography
  • Free Printable Periodic Tables (PDF and PNG)
  • Periodic Table Wallpapers
  • Interactive Periodic Table
  • Periodic Table Posters
  • How to Grow Crystals
  • Chemistry Projects
  • Fire and Flames Projects
  • Holiday Science
  • Chemistry Problems With Answers
  • Physics Problems
  • Unit Conversion Example Problems
  • Chemistry Worksheets
  • Biology Worksheets
  • Periodic Table Worksheets
  • Physical Science Worksheets
  • Science Lab Worksheets
  • My Amazon Books

What Are the Products of Photosynthesis?

Products of Photosynthesis

Photosynthesis is a set of chemical reactions that plants and other organisms use to make chemical energy in the form of sugar. Like any chemical reaction, photosynthesis has reactants and products . Overall, the reactants of photosynthesis are carbon dioxide and water, while the products of photosynthesis are oxygen and glucose (a sugar).

Here’s a closer look at the products of photosynthesis and the balanced equation for the reaction.

The reactants for photosynthesis are carbon dioxide and water, while the products are the sugar glucose and oxygen.

Balanced Chemical Equation for Photosynthesis

Photosynthesis actually involves many chemical reactions, but the net balanced equation is that six moles of carbon dioxide react with six moles of water to produce one mole of glucose and six moles of oxygen. Light from the Sun provides the activation energy for the reaction. Sometimes light is listed in the balanced equation as a reactant, but it’s usually omitted.

6 CO 2  + 6 H 2 O → C 6 H 12 O 6  + 6 O 2

Carbon Dioxide + Water + Light → Glucose + Oxygen

Closer Look at the Products of Photosynthesis

Photosynthesis occurs in a series of steps that are classified as light-dependent reactions and light-independent reactions. Adding up the reactants and products of these reactions gives the overall equation for photosynthesis, but it’s good to know the inputs and outputs for each stage.

Light-Dependent Reactions

Photosynthesis Overview

The light-dependent reactions or light reactions absorb certain wavelengths of light to make adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide phosphate (NADPH). The light reactions occur in the chloroplast thylakoid membrane. The overall balanced equation for the light-dependent reactions is:

2 H 2 O + 2 NADP +  + 3 ADP + 3 P i  + light → 2 NADPH + 2 H +  + 3 ATP + O 2

Light-Independent Reactions

While the light reactions use water, the light-independent reactions use carbon dioxide. The light-independent reactions are also called the dark reactions. These reactions do not require darkness, but they don’t depend on light to proceed. In plants, algae, and cyanobacteria, the dark reactions are called the Calvin cycle. Bacteria use different reactions, including the reverse Krebs cycle.

The overall balanced equation for the light-independent reactions (Calvin cycle) in plants is:

3 CO 2  + 9 ATP + 6 NADPH + 6 H +  → C 3 H 6 O 3 -phosphate + 9 ADP + 8 P i  + 6 NADP +  + 3 H 2 O

Finally, the three-carbon product from the Calvin cycle becomes glucose during the process of carbon fixation.

Other Products of Photosynthesis

Glucose is the direct product of photosynthesis, but plants turn most of the sugar into other compounds. These are indirect products. Linking glucose units forms starch and cellulose. Cellulose is a structural material. Plants store starch or link it to fructose (another sugar) to form sucrose (table sugar).

What Is Not a Product of Photosynthesis?

On an exam, you may need to identify which chemical is not a product of photosynthesis. For the overall process, choose any answer except “glucose” or “oxygen.” It’s good to know the overall reactants and products of the light reactions and dark reactions, in case you’re asked about them. The products of the light reactions are ATP , NADPH, protons, and oxygen. The products of the dark reactions are C 3 H 6 O 3 -phosphate, ADP, inorganic phosphate, NADP + , and water.

Where Does Photosynthesis Occur?

In addition to knowing the reactants and products of photosynthesis, you may need to know where photosynthesis occurs in different organisms.

  • In plants, photosynthesis occurs in organelles called chloroplasts. Photosynthetic protists also contain chloroplasts. Leaves contain the highest concentration of chloroplasts in plants. Plants obtain carbon dioxide via diffusion through leaf stomata. Water comes from the roots and travels to the leaves via the xylem . Chlorophyll in chloroplasts absorbs solar energy. Oxygen from photosynthesis exits the plant via leaf stomata.
  • Photosynthesis occurs in photosynthetic bacteria in the plasma membrane. Chlorophyll or related pigments are embedded in this membrane.
  • Bidlack, J.E.; Stern, K.R.; Jansky, S. (2003).  Introductory Plant Biology . New York: McGraw-Hill. ISBN 978-0-07-290941-8.
  • Blankenship, R.E. (2014).  Molecular Mechanisms of Photosynthesis  (2nd ed.). John Wiley & Sons. ISBN 978-1-4051-8975-0.
  • Reece J.B., et al. (2013).  Campbell Biology . Benjamin Cummings. ISBN 978-0-321-77565-8.

Related Posts

Visible Body Learn Anatomy

  • Overview of Cells
  • Prokaryotic Cells
  • Eukaryotic Cells
  • Prokaryotic vs. Eukaryotic Cells
  • Monocot and Dicot Overview
  • Monocot and Dicot Roots
  • Monocot and Dicot Stems
  • Monocot and Dicot Leaves
  • Monocot Glossary
  • Dicot Glossary
  • DNA and Chromosomes Overview
  • Eukaryotic Chromosomes
  • Prokaryotic Chromosomes
  • Eukaryotic vs. Prokaryotic Chromosomes
  • DNA Structure
  • Red Blood Cells and Platelets
  • Granular Myeloid White Blood Cells
  • Agranular Myeloid White Blood Cells
  • Lymphoid White Blood Cells
  • Reactants and Products

Leaf Structures

Photosynthesis Reactions

  • Evolution Overview
  • Mechanisms of Evolution

Visible Body Learn Biology

Photosynthesis: Reactants and Products

© 2024 Visible Body

Photosynthesis

what end product is the main goal of photosynthesis

1. Photosynthesis is the process plants use to make their own food.

Like all living things, plants need energy to carry out the processes that keep them alive. They get this energy from food. Humans and most other animals are heterotrophs, meaning we have to consume other organisms—plants, other animals, or some combination of the two—for food. However, plants are autotrophs, meaning they create their own food.

Plants use sunlight to convert water and carbon dioxide into glucose and oxygen in a process called photosynthesis . In biology, this information is often expressed using a chemical equation .

Chemical equations typically show the molecules that enter the reaction (the reactants ) to the left and the molecules that result from the reaction (the products ) to the right, separated by an arrow that indicates a reaction taking place.

[Reactants] → [Products]

You can think of the reactants as the ingredients for preparing a meal and the products as the different dishes in that meal.

With that in mind, let’s take a look at the chemical equation for photosynthesis:

Sunlight + 6 CO 2 + 6 H 2 O → C 6 H 12 O 6 + 6 O 2 CO 2 = carbon dioxide H 2 O = water C 6 H 12 O 6 = glucose O 2 = oxygen * Sometimes, you’ll see sunlight, or a symbol indicating the sun, over the arrow in the equation.

Therefore, to produce one molecule of glucose (and 6 molecules of oxygen gas), a plant needs 6 molecules of carbon dioxide and 6 molecules of water.

2. The reactants of photosynthesis are carbon dioxide and water.

We’ve established that plants need carbon dioxide (CO 2 ) and water (H 2 O) to produce their food, but where do these reactants come from and how do they get where they need to go inside the plant?

Plants take in carbon dioxide from the air through small openings in their leaves called stomata. Some plants (most monocots) have stomata on both sides of their leaves, and others (dicots and a few monocots) only have stomata on the underside, or lower epidermis.

Plants take in carbon dioxide from the air through small openings in their leaves called stomata.

Plants get water from the soil surrounding their roots, and water gets to the leaves by traveling through the xylem, part of the plant’s vascular system. In leaves, the xylem and phloem are contained in the vascular bundle.

Once inside the leaf, the carbon dioxide and water molecules move into the cells of the mesophyll, the layer of ground tissue between the upper and lower epidermis. Within these cells, organelles called chloroplasts use the carbon dioxide and water to carry out photosynthesis.

3. Light energy from the sun initiates photosynthesis in the chloroplasts of plant cells.

Plant cells have special organelles called chloroplasts, which serve as the sites for the reactions that make up photosynthesis. Their thylakoid membranes contain a pigment called chlorophyll, which absorbs photons (light energy) from the sun, initiating the light-dependent reactions that take place within the thylakoids.

Chloroplasts are organelles within plant cells that serve as the sites for the reactions that make up photosynthesis.

During these reactions, water molecules (H 2 O) are broken down. NADPH and ATP—high energy molecules that power the production of glucose—are produced during the light-dependent reactions, as well. Electrons and hydrogen ions from the water are used to build NADPH. Hydrogen ions also power the conversion of ADP to ATP.

4. The products of photosynthesis are glucose and oxygen.

Did you know that oxygen is actually a waste product of photosynthesis? Although the hydrogen atoms from the water molecules are used in the photosynthesis reactions, the oxygen molecules are released as oxygen gas (O 2 ). (This is good news for organisms like humans and plants that use oxygen to carry out cellular respiration!) Oxygen passes out of the leaves through the stomata.

The light-independent reactions of photosynthesis—also known as the Calvin cycle—use enzymes in the stroma, along with the energy-carrying molecules (ATP and NADPH) from the light-dependent reactions, to break down carbon dioxide molecules (CO 2 ) into a form that is used to build glucose.The mitochondria in the plant’s cells use cellular respiration to break glucose down into a usable form of energy (ATP), which fuels all the plant’s activities.

After the light-independent reactions, glucose is often made into larger sugars like sucrose or carbohydrates like starch or cellulose. Sugars leave the leaf through the phloem and can travel to the roots for storage or to other parts of the plant, where they’re used as energy to fuel the plant’s activities.

Download lab activities

Download biology eBooks

External Sources

An article on chemical equation notation from cK-12.

Related Articles

3D rendering of a dissected frog with the words "A biology course for everyone"

For students

For instructors

Get our awesome anatomy emails!

When you select "Subscribe" you will start receiving our email newsletter. Use the links at the bottom of any email to manage the type of emails you receive or to unsubscribe. See our privacy policy for additional details.

  • User Agreement
  • Permissions

ENCYCLOPEDIC ENTRY

Photosynthesis.

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

Loading ...

Learning materials, instructional links.

  • Photosynthesis (Google doc)

Most life on Earth depends on photosynthesis .The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O 2 ) and chemical energy stored in glucose (a sugar). Herbivores then obtain this energy by eating plants, and carnivores obtain it by eating herbivores.

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. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

Chlorophyll

Inside the plant cell are small organelles called chloroplasts , which store the energy of sunlight. Within the thylakoid membranes of the chloroplast is a light-absorbing pigment called chlorophyll , which is responsible for giving the plant its green color. During photosynthesis , chlorophyll absorbs energy from blue- and red-light waves, and reflects green-light waves, making the plant appear green.

Light-dependent Reactions vs. Light-independent Reactions

While there are many steps behind the process of photosynthesis, it can be broken down into two major stages: light-dependent reactions and light-independent reactions. The light-dependent reaction takes place within the thylakoid membrane and requires a steady stream of sunlight, hence the name light- dependent reaction. The chlorophyll absorbs energy from the light waves, which is converted into chemical energy in the form of the molecules ATP and NADPH . The light-independent stage, also known as the Calvin cycle , takes place in the stroma , the space between the thylakoid membranes and the chloroplast membranes, and does not require light, hence the name light- independent reaction. During this stage, energy from the ATP and NADPH molecules is used to assemble carbohydrate molecules, like glucose, from carbon dioxide.

C3 and C4 Photosynthesis

Not all forms of photosynthesis are created equal, however. There are different types of photosynthesis, including C3 photosynthesis and C4 photosynthesis. C3 photosynthesis is used by the majority of plants. It involves producing a three-carbon compound called 3-phosphoglyceric acid during the Calvin Cycle, which goes on to become glucose. C4 photosynthesis, on the other hand, produces a four-carbon intermediate compound, which splits into carbon dioxide and a three-carbon compound during the Calvin Cycle. A benefit of C4 photosynthesis is that by producing higher levels of carbon, it allows plants to thrive in environments without much light or water. The National Geographic Society is making this content available under a Creative Commons CC-BY-NC-SA license . The License excludes the National Geographic Logo (meaning the words National Geographic + the Yellow Border Logo) and any images that are included as part of each content piece. For clarity the Logo and images may not be removed, altered, or changed in any way.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Production Managers

Program specialists, last updated.

March 20, 2024

User Permissions

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text on this page is printable and can be used according to our Terms of Service .

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources

What Are the Products of Photosynthesis?

Result of Photosynthesis in Plants

  • Biochemistry
  • Chemical Laws
  • Periodic Table
  • Projects & Experiments
  • Scientific Method
  • Physical Chemistry
  • Medical Chemistry
  • Chemistry In Everyday Life
  • Famous Chemists
  • Activities for Kids
  • Abbreviations & Acronyms
  • Weather & Climate
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College

Photosynthesis is the name given to the set of chemical reactions performed by plants to convert energy from the sun into chemical energy in the form of sugar. Specifically, plants use energy from sunlight to react carbon dioxide and water to produce sugar ( glucose ) and oxygen . Many reactions occur, but the overall chemical reaction for photosynthesis is:

  • 6 CO 2 + 6 H 2 O + light → C 6 H 12 O 6 + 6 O 2
  • Carbon Dioxide + Water + Light yields Glucose + Oxygen

In a plant, the carbon dioxide enters via leaf stomates by diffusion . Water is absorbed through the roots and is transported to leaves through the xylem. Solar energy is absorbed by chlorophyll in the leaves. The reactions of photosynthesis occur in the chloroplasts of plants. In photosynthetic bacteria, the process takes place where chlorophyll or a related pigment is embedded in the plasma membrane. The oxygen and water produced in photosynthesis exit through the stomata.

Key Takeaways

  • In photosynthesis, energy from light is used to convert carbon dioxide and water into glucose and oxygen.
  • For 6 carbon dioxide and 6 water molecules, 1 glucose molecule and 6 oxygen molecules are produced.

Actually, plants reserve very little of the glucose for immediate use. Glucose molecules are combined by dehydration synthesis to form cellulose, which is used as a structural material. Dehydration synthesis is also used to convert glucose to starch, which plants use to store energy.

Intermediate Products of Photosynthesis

The overall chemical equation is a summary of a series of chemical reactions. These reactions occur in two stages. The light reactions require light (as you might imagine), while the dark reactions are controlled by enzymes. They don't require darkness to occur -- they simply don't depend on light.

The light reactions absorb light and harness the energy to power electron transfers. Most photosynthetic organisms capture visible light, although there are some that use infrared light. Products of these reactions are adenosine triphosphate ( ATP ) and reduced nicotinamide adenine dinucleotide phosphate (NADPH). In plant cells, the light-dependent reactions occur in the chloroplast thylakoid membrane. The overall reaction for the light-dependent reactions is:

  • 2 H 2 O + 2 NADP +  + 3 ADP + 3 P i  + light → 2 NADPH + 2 H +  + 3 ATP + O 2

In the dark stage, ATP and NADPH ultimately reduce carbon dioxide and other molecules. Carbon dioxide from the air is "fixed" into a biologically usable form, glucose. In plants, algae, and cyanobacteria, the dark reactions are termed the Calvin cycle. Bacteria may use different reactions, including a reverse Krebs cycle . The overall reaction for the light-independent reaction of a plant (Calvin cycle) is:

  • 3 CO 2  + 9 ATP + 6 NADPH + 6 H +  → C 3 H 6 O 3 -phosphate + 9 ADP + 8 P i  + 6 NADP +  + 3 H 2 O

During carbon fixation, the three-carbon product of the Calvin cycle is converted into the final carbohydrate product.

Factors That Affect the Rate of Photosynthesis

Like any chemical reaction, the availability of the reactants determines the amount of products that can be made. Limiting the availability of carbon dioxide or water slows the production of glucose and oxygen. Also, the rate of the reactions is affected by temperature and the availability of minerals that may be needed in the intermediate reactions.

The overall health of the plant (or other photosynthetic organism) also plays a role. The rate of metabolic reactions is determined in part by the maturity of the organism and whether it's flowering or bearing fruit.

What Is Not a Product of Photosynthesis?

If you're asked about photosynthesis on a test, you may be asked to identify the products of the reaction. That's pretty easy, right? Another form of the question is to ask what is not a product of photosynthesis. Unfortunately, this won't be an open-ended question, which you could easily answer with "iron" or "a car" or "your mom." Usually this is a multiple choice question, listing molecules which are reactants or products of photosynthesis. The answer is any choice except glucose or oxygen. The question may also be phrased to answer what is not a product of the light reactions or the dark reactions. So, it's a good idea to know the overall reactants and products for the photosynthesis general equation, the light reactions, and the dark reactions.

  • Bidlack, J.E.; Stern, K.R.; Jansky, S. (2003). Introductory Plant Biology . New York: McGraw-Hill. ISBN 978-0-07-290941-8.
  • Blankenship, R.E. (2014). Molecular Mechanisms of Photosynthesis (2nd ed.). John Wiley & Sons. ISBN 978-1-4051-8975-0.
  • Reece J.B., et al. (2013). Campbell Biology . Benjamin Cummings. ISBN 978-0-321-77565-8.
  • Photosynthesis Basics - Study Guide
  • Photosynthesis Vocabulary Terms and Definitions
  • The Photosynthesis Formula: Turning Sunlight into Energy
  • Calvin Cycle Steps and Diagram
  • 10 Fascinating Photosynthesis Facts
  • Chloroplast Function in Photosynthesis
  • Chlorophyll Definition and Role in Photosynthesis
  • What Is the Primary Function of the Calvin Cycle?
  • The Balanced Chemical Equation for Photosynthesis
  • All About Photosynthetic Organisms
  • Examples of Chemical Reactions in Everyday Life
  • Thylakoid Definition and Function
  • Simple Chemical Reactions
  • Chemosynthesis Definition and Examples
  • An Introduction to Types of Respiration
  • Understanding Endothermic and Exothermic Reactions

5.2 The Light-Dependent Reactions of Photosynthesis

Learning objectives.

  • Explain how plants absorb energy from sunlight
  • Describe how the wavelength of light affects its energy and color
  • Describe how and where photosynthesis takes place within a plant

How can light be used to make food? It is easy to think of light as something that exists and allows living organisms, such as humans, to see, but light is a form of energy. Like all energy, light can travel, change form, and be harnessed to do work. In the case of photosynthesis, light energy is transformed into chemical energy, which autotrophs use to build carbohydrate molecules. However, autotrophs only use a specific component of sunlight ( Figure 5.8 ).

Link to Learning

Watch the process of photosynthesis within a leaf in this video.

What Is Light Energy?

The sun emits an enormous amount of electromagnetic radiation (solar energy). Humans can see only a fraction of this energy, which is referred to as “visible light.” The manner in which solar energy travels can be described and measured as waves. Scientists can determine the amount of energy of a wave by measuring its wavelength , the distance between two consecutive, similar points in a series of waves, such as from crest to crest or trough to trough ( Figure 5.9 ).

Visible light constitutes only one of many types of electromagnetic radiation emitted from the sun. The electromagnetic spectrum is the range of all possible wavelengths of radiation ( Figure 5.10 ). Each wavelength corresponds to a different amount of energy carried.

Each type of electromagnetic radiation has a characteristic range of wavelengths. The longer the wavelength (or the more stretched out it appears), the less energy is carried. Short, tight waves carry the most energy. This may seem illogical, but think of it in terms of a piece of moving rope. It takes little effort by a person to move a rope in long, wide waves. To make a rope move in short, tight waves, a person would need to apply significantly more energy.

The sun emits ( Figure 5.10 ) a broad range of electromagnetic radiation, including X-rays and ultraviolet (UV) rays. The higher-energy waves are dangerous to living things; for example, X-rays and UV rays can be harmful to humans.

Absorption of Light

Light energy enters the process of photosynthesis when pigments absorb the light. In plants, pigment molecules absorb only visible light for photosynthesis. The visible light seen by humans as white light actually exists in a rainbow of colors. Certain objects, such as a prism or a drop of water, disperse white light to reveal these colors to the human eye. The visible light portion of the electromagnetic spectrum is perceived by the human eye as a rainbow of colors, with violet and blue having shorter wavelengths and, therefore, higher energy. At the other end of the spectrum toward red, the wavelengths are longer and have lower energy.

Understanding Pigments

Different kinds of pigments exist, and each absorbs only certain wavelengths (colors) of visible light. Pigments reflect the color of the wavelengths that they cannot absorb.

All photosynthetic organisms contain a pigment called chlorophyll a , which humans see as the common green color associated with plants. Chlorophyll a absorbs wavelengths from either end of the visible spectrum (blue and red), but not from green. Because green is reflected, chlorophyll appears green.

Other pigment types include chlorophyll b (which absorbs blue and red-orange light) and the carotenoids. Each type of pigment can be identified by the specific pattern of wavelengths it absorbs from visible light, which is its absorption spectrum .

Many photosynthetic organisms have a mixture of pigments; between them, the organism can absorb energy from a wider range of visible-light wavelengths. Not all photosynthetic organisms have full access to sunlight. Some organisms grow underwater where light intensity decreases with depth, and certain wavelengths are absorbed by the water. Other organisms grow in competition for light. Plants on the rainforest floor must be able to absorb any bit of light that comes through, because the taller trees block most of the sunlight ( Figure 5.11 ).

How Light-Dependent Reactions Work

The overall purpose of the light-dependent reactions is to convert light energy into chemical energy. This chemical energy will be used by the Calvin cycle to fuel the assembly of sugar molecules.

The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem . Photosystems exist in the membranes of thylakoids. A pigment molecule in the photosystem absorbs one photon , a quantity or “packet” of light energy, at a time.

A photon of light energy travels until it reaches a molecule of chlorophyll. The photon causes an electron in the chlorophyll to become “excited.” The energy given to the electron allows it to break free from an atom of the chlorophyll molecule. Chlorophyll is therefore said to “donate” an electron ( Figure 5.12 ).

To replace the electron in the chlorophyll, a molecule of water is split. This splitting releases an electron and results in the formation of oxygen (O 2 ) and hydrogen ions (H + ) in the thylakoid space. Technically, each breaking of a water molecule releases a pair of electrons, and therefore can replace two donated electrons.

The replacing of the electron enables chlorophyll to respond to another photon. The oxygen molecules produced as byproducts find their way to the surrounding environment. The hydrogen ions play critical roles in the remainder of the light-dependent reactions.

Keep in mind that the purpose of the light-dependent reactions is to convert solar energy into chemical carriers that will be used in the Calvin cycle. In eukaryotes and some prokaryotes, two photosystems exist. The first is called photosystem II, which was named for the order of its discovery rather than for the order of the function.

After the photon hits, photosystem II transfers the free electron to the first in a series of proteins inside the thylakoid membrane called the electron transport chain. As the electron passes along these proteins, energy from the electron fuels membrane pumps that actively move hydrogen ions against their concentration gradient from the stroma into the thylakoid space. This is quite analogous to the process that occurs in the mitochondrion in which an electron transport chain pumps hydrogen ions from the mitochondrial stroma across the inner membrane and into the intermembrane space, creating an electrochemical gradient. After the energy is used, the electron is accepted by a pigment molecule in the next photosystem, which is called photosystem I ( Figure 5.13 ).

Generating an Energy Carrier: ATP

In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. The energy that these molecules carry is stored in a bond that holds a single atom or group of atoms to the molecule. For ATP, it is a phosphate group, and for NADPH, it is a hydrogen atom. Recall that NADH was a similar molecule that carried energy in the mitochondrion from the citric acid cycle to the electron transport chain. When these molecules release energy into the Calvin cycle, they each lose either atoms or groups of atoms to become the lower-energy molecules ADP and NADP + .

The buildup of hydrogen ions in the thylakoid space forms an electrochemical gradient because of the difference in the concentration of protons (H + ) and the difference in the charge across the membrane that they create. This potential energy is harvested and stored as chemical energy in ATP through chemiosmosis, the movement of hydrogen ions down their electrochemical gradient through the transmembrane enzyme ATP synthase, just as in the mitochondrion.

The hydrogen ions are allowed to pass through the thylakoid membrane through an embedded protein complex called ATP synthase. This same protein generated ATP from ADP in the mitochondrion. The energy generated by the hydrogen ion stream allows ATP synthase to attach a third phosphate to ADP, which forms a molecule of ATP in a process called photophosphorylation. The flow of hydrogen ions through ATP synthase is called chemiosmosis, because the ions move from an area of high to low concentration through a semi-permeable structure.

Generating Another Energy Carrier: NADPH

The remaining function of the light-dependent reaction is to generate the other energy-carrier molecule, NADPH. As the electron from the electron transport chain arrives at photosystem I, it is re-energized with another photon captured by chlorophyll. The energy from this electron drives the formation of NADPH from NADP + and a hydrogen ion (H + ). Now that the solar energy is stored in energy carriers, it can be used to make a sugar molecule.

As an Amazon Associate we earn from qualifying purchases.

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute OpenStax.

Access for free at https://openstax.org/books/concepts-biology/pages/1-introduction
  • Authors: Samantha Fowler, Rebecca Roush, James Wise
  • Publisher/website: OpenStax
  • Book title: Concepts of Biology
  • Publication date: Apr 25, 2013
  • Location: Houston, Texas
  • Book URL: https://openstax.org/books/concepts-biology/pages/1-introduction
  • Section URL: https://openstax.org/books/concepts-biology/pages/5-2-the-light-dependent-reactions-of-photosynthesis

© Jan 8, 2024 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License . The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.

If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

To log in and use all the features of Khan Academy, please enable JavaScript in your browser.

AP®︎/College Biology

Course: ap®︎/college biology   >   unit 3.

  • Photosynthesis
  • Intro to photosynthesis
  • Breaking down photosynthesis stages
  • Conceptual overview of light dependent reactions

The light-dependent reactions

  • The Calvin cycle
  • Photosynthesis evolution
  • Photosynthesis review

Introduction

  • Plants carry out a form of photosynthesis called oxygenic photosynthesis . In oxygenic photosynthesis, water molecules are split to provide a source of electrons for the electron transport chain, and oxygen gas is released as a byproduct. Plants organize their photosynthetic pigments into two separate complexes called photosystems (photosystems I and II), and they use chlorophylls as their reaction center pigments.
  • Purple sulfur bacteria, in contrast, carry out anoxygenic photosynthesis , meaning that water is not used as an electron source and oxygen gas is not produced. Instead, these bacteria use hydrogen sulfide ( H 2 S ‍   ) as an electron source and produce elemental sulfur as a byproduct. In addition, purple sulfur bacteria have only one photosystem, and they use chlorophyll-like molecules called bacteriochlorophylls as reaction center pigments 1 , 2 , 3 ‍   .

Overview of the light-dependent reactions

  • Light absorption in PSII. When light is absorbed by one of the many pigments in photosystem II, energy is passed inward from pigment to pigment until it reaches the reaction center. There, energy is transferred to P680, boosting an electron to a high energy level. The high-energy electron is passed to an acceptor molecule and replaced with an electron from water. This splitting of water releases the O 2 ‍   we breathe.
  • ATP synthesis. The high-energy electron travels down an electron transport chain, losing energy as it goes. Some of the released energy drives pumping of H + ‍   ions from the stroma into the thylakoid interior, building a gradient. ( H + ‍   ions from the splitting of water also add to the gradient.) As H + ‍   ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as chemiosmosis .
  • Light absorption in PSI. The electron arrives at photosystem I and joins the P700 special pair of chlorophylls in the reaction center. When light energy is absorbed by pigments and passed inward to the reaction center, the electron in P700 is boosted to a very high energy level and transferred to an acceptor molecule. The special pair's missing electron is replaced by a new electron from PSII (arriving via the electron transport chain).
  • NADPH formation. The high-energy electron travels down a short second leg of the electron transport chain. At the end of the chain, the electron is passed to NADP + ‍   (along with a second electron from the same pathway) to make NADPH.

What is a photosystem?

Photosystem i vs. photosystem ii.

  • Special pairs. The chlorophyll a special pairs of the two photosystems absorb different wavelengths of light. The PSII special pair absorbs best at 680 nm, while the PSI special absorbs best at 700 nm. Because of this, the special pairs are called P680 and P700 , respectively.
  • Primary acceptor . The special pair of each photosystem passes electrons to a different primary acceptor. The primary electron acceptor of PSII is pheophytin, an organic molecule that resembles chlorophyll, while the primary electron acceptor of PSI is a chlorophyll called A 0 ‍   7 , 8 ‍   .
  • Source of electrons . Once an electron is lost, each photosystem is replenished by electrons from a different source. The PSII reaction center gets electrons from water, while the PSI reaction center is replenished by electrons that flow down an electron transport chain from PSII.

Photosystem II

Electron transport chains and photosystem i, some electrons flow cyclically, attribution:, works cited:.

  • Lodish, H., Berk, A., Zipursky, S. L., Matsudaira, P., Baltimore, D., and Darnell, J. (2000). Molecular analysis of photosystems. In Molecular cell biology (4th ed., section 16.4). New York, NY: W. H. Freeman. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK21484/ .
  • Boundless. (2015, July 21). Anoxygenic photosynthetic bacteria. In Boundless microbiology . Retrieved from https://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/microbial-evolution-phylogeny-and-diversity-8/nonproteobacteria-gram-negative-bacteria-105/anoxygenic-photosynthetic-bacteria-551-7338/ .
  • Purple sulfur bacteria. (2015, July 16). Retrieved October 24, 2015 from Wikipedia: https://en.wikipedia.org/wiki/Purple_sulfur_bacteria .
  • Soda lake. (2015, September 26). Retrieved October 24, 2015 from Wikipedia: https://en.wikipedia.org/wiki/Soda_lake .
  • Gutierrez, R. Bio41 Week 7 Biochemistry Lectures 11 and 12. Bio41. 2009.
  • Berg, J. M., Tymoczko, J. L., and Stryer, L. (2002). Accessory pigments funnel energy into reaction centers. In Biochemistry (5th ed., section 19.5). New York, NY: W. H. Freeman. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK22604/ .
  • Pheophytin. (2015, February 11). Retrieved October 28, 2015 from Wikipedia: https://en.wikipedia.org/wiki/Pheophytin .
  • Photosystem I. (2016, June 25). Retrieved from Wikipedia on July 22, 2016: https://en.wikipedia.org/wiki/Photosystem_I .
  • Berg, J. M., Tymoczko, J. L., and Stryer, L. (2002). Two photosystems generate a proton gradient and NADPH in oxygenic photosynthesis. In Biochemistry (5th ed., section 19.3). New York, NY: W. H. Freeman. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK22538/#_A2681_ .
  • Joliot, P. and Johnson, G. N. (2011). Regulation of cyclic and linear electron flow in higher plants. PNAS, 108(32), 13317-13322. http://dx.doi.org/10.1073/pnas.1110189108 .
  • Johnson, Giles N. (2011). Physiology of PSI cyclic electron transport in higher plants. Biochimica et Biophysica Acta - Bioenergetics , 1807 (8), 906-911. http://dx.doi.org/doi:10.1016/j.bbabio.2010.11.009 .
  • Berg, J. M., Tymoczko, J. L., and Stryer, L. (2002). A proton gradient across the thylakoid membrane drives ATP synthesis. In Biochemistry (5th ed., section 19.4). New York, NY: W. H. Freeman. Retrieved from http://www.ncbi.nlm.nih.gov/books/NBK22519/ .
  • Takahashi, S., Milward, S. E., Fan, D.-Y., Chow, W. S., and Badger, M. R. (2008). How does cyclic electron flow alleviate photoinhibition in Arabidopsis? Plant Physiology , 149 (3), 1560-1567. http://dx.doi.org/10.1104/pp.108.134122 .

Additional references:

Want to join the conversation.

  • Upvote Button navigates to signup page
  • Downvote Button navigates to signup page
  • Flag Button navigates to signup page

Great Answer

Library homepage

  • school Campus Bookshelves
  • menu_book Bookshelves
  • perm_media Learning Objects
  • login Login
  • how_to_reg Request Instructor Account
  • hub Instructor Commons
  • Download Page (PDF)
  • Download Full Book (PDF)
  • Periodic Table
  • Physics Constants
  • Scientific Calculator
  • Reference & Cite
  • Tools expand_more
  • Readability

selected template will load here

This action is not available.

Biology LibreTexts

10.5: The Light Independent Reactions (aka the Calvin Cycle)

  • Last updated
  • Save as PDF
  • Page ID 69980

After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules come from carbon dioxide, which diffuses into the leaves through the stomata. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules ( Figure \(\PageIndex{1}\) ).

calvin cycle

The Interworkings of the Calvin Cycle

In plants, carbon dioxide (CO 2 ) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplast—the site of the Calvin cycle reactions where sugar is synthesized. The reactions are named after the scientist who discovered them, and reference the fact that the reactions function as a cycle. Others call it the Calvin-Benson cycle to include the name of another scientist involved in its discovery.

photosynthesis in its entirety

The Calvin cycle reactions ( Figure \(\PageIndex{2}\) ) can be organized into three basic stages: fixation, reduction, and regeneration. In the stroma, in addition to CO 2 , two other molecules are present to initiate the Calvin cycle: an enzyme abbreviated RuBisCO (which stands for ribulose-1,5-bisphosphate carboxylase/oxygenase, in case you’re interested), and the molecule ribulose bisphosphate (RuBP). RuBP has five atoms of carbon and a phosphate group on each end.

A diagram of the Calvin cycle is shown with its three stages: carbon fixation, 3-PGA reduction, and regeneration of RuBP. In stage 1, the enzyme RuBisCO adds a carbon dioxide to the five-carbon molecule RuBP, producing two three-carbon 3-PGA molecules. In stage 2, two NADPH and two ATP are used to reduce 3-PGA to GA3P. In stage 3 RuBP is regenerated from GA3P. One ATP is used in the process. Three complete cycles produces one new GA3P, which is shunted out of the cycle and made into glucose (C6H12O6).

RuBisCO catalyzes a reaction between CO 2 and RuBP, which forms a six-carbon compound that is immediately converted into two three-carbon compounds. This process is called carbon fixation , because CO 2 is “fixed” from its inorganic form into organic molecules. You can think this as the carbon being converted from the “broken” form in CO 2 (which organisms are not able to directly use) into a “fixed” form, which organisms are able to utilize. Because of this very important role in photosynthesis, RuBisCO is probably the most abundant enzyme on earth.

ATP and NADPH use their stored energy to convert the three-carbon compound, 3-PGA, into another three-carbon compound called G3P. This type of reaction is called a reduction reaction, because it involves the gain of electrons. A reduction is the gain of an electron by an atom or molecule. The molecules of ADP and NAD + , resulting from the reduction reaction, return to the light-dependent reactions to be re-energized.

One of the G3P molecules leaves the Calvin cycle to contribute to the formation of the carbohydrate molecule, which is commonly glucose (C 6 H 12 O 6 ). Because the carbohydrate molecule has six carbon atoms, it takes six turns of the Calvin cycle to make one carbohydrate molecule (one for each carbon dioxide molecule fixed). The remaining G3P molecules regenerate RuBP, which enables the system to prepare for the carbon-fixation step. ATP is also used in the regeneration of RuBP.

In summary, it takes six turns of the Calvin cycle to fix six carbon atoms from CO 2 . These six turns require energy input from 12 ATP molecules and 12 NADPH molecules in the reduction step and 6 ATP molecules in the regeneration step.

Evolution Connection

Photosynthesis in desert plants has evolved adaptations that conserve water. In the harsh dry heat, every drop of water must be used to survive. Because stomata must open to allow for the uptake of CO 2 , water escapes from the leaf during active photosynthesis. Desert plants have evolved processes to conserve water and deal with harsh conditions. A more efficient use of CO 2 allows plants to adapt to living with less water. Some plants such as cacti can prepare materials for photosynthesis during the night by a temporary carbon fixation/storage process, because opening the stomata at this time conserves water due to cooler temperatures. In addition, cacti have evolved the ability to carry out low levels of photosynthesis without opening stomata at all, an extreme mechanism to face extremely dry periods.

Section Summary

Using the energy carriers formed in the first steps of photosynthesis, the light-independent reactions, or the Calvin cycle, take in CO 2 from the environment. An enzyme, RuBisCO, catalyzes a reaction with CO 2 and another molecule, RuBP. After three cycles, a three-carbon molecule of G3P leaves the cycle to become part of a carbohydrate molecule. The remaining G3P molecules stay in the cycle to be regenerated into RuBP, which is then ready to react with more CO 2 . Photosynthesis forms an energy cycle with the process of cellular respiration. Plants need both photosynthesis and respiration for their ability to function in both the light and dark, and to be able to interconvert essential metabolites. Therefore, plants contain both chloroplasts and mitochondria.

Query \(\PageIndex{1}\)

Unless otherwise noted, images on this page are licensed under CC-BY 4.0  by  OpenStax .

Text adapted from: OpenStax , Concepts of Biology. OpenStax CNX. May 18, 2016 http://cnx.org/contents/[email protected]

IMAGES

  1. Photosynthesis Explained

    what end product is the main goal of photosynthesis

  2. What Are the Products of Photosynthesis?

    what end product is the main goal of photosynthesis

  3. Photosynthesis, the green engine of life on Earth

    what end product is the main goal of photosynthesis

  4. Photosynthesis Diagram

    what end product is the main goal of photosynthesis

  5. Two Stages of Photosynthesis

    what end product is the main goal of photosynthesis

  6. [Class 7] Photosynthesis

    what end product is the main goal of photosynthesis

VIDEO

  1. Why is photosynthesis important to humans?

  2. Photosynthesis in Higher Plats Teaser

  3. What are the 4 end products of photosynthesis?

  4. What are the 3 stages of photosynthesis?

  5. Photosynthesis

  6. A detailed Lecture About Calvin Cycle| Definition| Discovery| Alternative Names

COMMENTS

  1. What Is the End Product of Photosynthesis?

    The Formula. The formula associated with the process of photosynthesis is. 6H 2 O + 6CO 2 = C 6 H 12 O 6 + 6O 2. This formula tells you is that six molecules of water plus six molecules of carbon dioxide will produce one molecule of glucose plus six molecules of oxygen. This entire process goes through two distinct stages before it is completed.

  2. Intro to photosynthesis (article)

    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 ...

  3. Photosynthesis

    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 ...

  4. Photosynthesis

    Besides sugars and sugar-based molecules, oxygen is the other main product of photosynthesis. Oxygen created from photosynthesis fuels every respiring organism on the planet. Quiz. 1. To complete the Calvin cycle, carbon dioxide is needed. Carbon dioxide reaches the interior of the plant via stomata, or small holes in the surface of a leaf. To ...

  5. 5.1: Overview of Photosynthesis

    Figure \(\PageIndex{3}\): Photosynthesis is the origin of the products that comprise the main elements of the human diet. (credit: Associação Brasileira de Supermercados) Although there is a large variety, each item links back to photosynthesis. Meats and dairy products link to photosynthesis because the animals were fed plant-based foods.

  6. Photosynthesis review (article)

    In photosynthesis, solar energy is harvested as chemical energy in a process that converts water and carbon dioxide to glucose. Oxygen is released as a byproduct. In cellular respiration, oxygen is used to break down glucose, releasing chemical energy and heat in the process. Carbon dioxide and water are products of this reaction.

  7. 8.1: Overview of Photosynthesis

    Main Structures and Summary of Photosynthesis. Photosynthesis is a multi-step process that requires sunlight, carbon dioxide (which is low in energy), and water as substrates (Figure 8.1.3 8.1. 3 ). After the process is complete, it releases oxygen and produces glyceraldehyde-3-phosphate (GA3P), simple carbohydrate molecules (which are high in ...

  8. The Purpose and Process of Photosynthesis

    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 ...

  9. Photosynthesis in organisms (article)

    Photosynthesis is powered by energy from sunlight. This energy is used to rearrange atoms in carbon dioxide and water to make oxygen and sugars. Carbon dioxide and water are inputs of photosynthesis. These inputs come from the environment. Oxygen and sugars are outputs of photosynthesis. The oxygen is released into the environment.

  10. 8.1 Overview of Photosynthesis

    Main Structures and Summary of Photosynthesis. Photosynthesis is a multi-step process that requires sunlight, carbon dioxide (which is low in energy), and water as substrates ().After the process is complete, it releases oxygen and produces glyceraldehyde-3-phosphate (GA3P), simple carbohydrate molecules (which are high in energy) that can subsequently be converted into glucose, sucrose, or ...

  11. Photosynthesis

    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.

  12. What Are the Products of Photosynthesis?

    The products of photosynthesis are glucose (a sugar) and oxygen. Photosynthesis is a set of chemical reactions that plants and other organisms use to make chemical energy in the form of sugar. Like any chemical reaction, photosynthesis has reactants and products. Overall, the reactants of photosynthesis are carbon dioxide and water, while the ...

  13. Photosynthesis: Reactants and Products

    During photosynthesis, light energy converts carbon dioxide and water (the reactants) into glucose and oxygen (the products). 1. Photosynthesis is the process plants use to make their own food. Like all living things, plants need energy to carry out the processes that keep them alive. They get this energy from food.

  14. Photosynthesis

    Photosynthesis (Google doc) Most life on Earth depends on photosynthesis .The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O 2) and chemical energy stored in glucose (a sugar). Herbivores then obtain this energy by eating plants, and carnivores obtain it by eating ...

  15. The Calvin cycle (article)

    In the Calvin cycle, carbon atoms from CO 2 are fixed (incorporated into organic molecules) and used to build three-carbon sugars. This process is fueled by, and dependent on, ATP and NADPH from the light reactions. Unlike the light reactions, which take place in the thylakoid membrane, the reactions of the Calvin cycle take place in the stroma ...

  16. What Are the Products of Photosynthesis?

    In photosynthesis, energy from light is used to convert carbon dioxide and water into glucose and oxygen. For 6 carbon dioxide and 6 water molecules, 1 glucose molecule and 6 oxygen molecules are produced. Actually, plants reserve very little of the glucose for immediate use. Glucose molecules are combined by dehydration synthesis to form ...

  17. 10.4: The Light-Dependent Reactions

    Photosynthesis takes place in two stages: the light-dependent reactions and the Calvin cycle. In the light-dependent reactions, which take place at the thylakoid membrane, chlorophyll absorbs energy from sunlight and then converts it into chemical energy with the use of water. The light-dependent reactions release oxygen as a byproduct as water ...

  18. 5.2 The Light-Dependent Reactions of Photosynthesis

    The overall purpose of the light-dependent reactions is to convert light energy into chemical energy. This chemical energy will be used by the Calvin cycle to fuel the assembly of sugar molecules. The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem. Photosystems exist in the membranes of ...

  19. The Two Parts of Photosynthesis

    Figure 8.3.1 8.3. 1: The two stages of photosynthesis: Photosynthesis takes place in two stages: light-dependent reactions and the Calvin cycle (light-independent reactions). 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 ...

  20. Photosynthesis Flashcards

    what is the main goal of photosynthesis? to turn light energy into chemical energy. equation for photosynthesis ... extensions that run from the tips of the roots all the way to the end oof the leaf. bundle sheath cells. outer layer of the vein, encircles the xylem and phloem. xylem. is surrounded by the bundle sheath cells. It makes up the ...

  21. 8.2: The Light-Dependent Reactions of Photosynthesis

    The overall function of light-dependent reactions is to convert solar energy into chemical energy in the form of NADPH and ATP. This chemical energy supports the light-independent reactions and fuels the assembly of sugar molecules. The light-dependent reactions are depicted in Figure 8.2.7 8.2. 7.

  22. Light-dependent reactions (photosynthesis reaction) (article)

    The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts.

  23. 10.5: The Light Independent Reactions (aka the Calvin Cycle)

    RuBP has five atoms of carbon and a phosphate group on each end. Figure 10.5.3 10.5. 3: The Calvin cycle has three stages. In stage 1, the enzyme RuBisCO incorporates carbon dioxide into an organic molecule, 3-PGA. In stage 2, the organic molecule is reduced using electrons supplied by NADPH. In stage 3, RuBP, the molecule that starts the cycle ...