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Photosynthesis for Kids: Light-dependent and Light-independent Reactions

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Photosynthesis for Kids: Light-dependent and Light-independent Reactions
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Ruth Knowunity

@knowunity.uk

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Photosynthesis is a complex process involving light-dependent and light-independent reactions. This summary covers the key steps, components, and factors affecting photosynthesis, with a focus on the light-dependent reactions and their products. It also touches on the Calvin cycle and limiting factors in photosynthesis.

  • Light-dependent reactions occur in thylakoid membranes, producing ATP and NADPH
  • Light-independent reactions (Calvin cycle) use these products to fix carbon dioxide
  • Key components include photosystems, electron transport chain, and ATP synthase
  • Limiting factors include temperature, CO2 concentration, and light intensity
  • Agricultural practices can optimize conditions for photosynthesis

01/10/2022

151

Light-Independent Reactions and the Calvin Cycle

The light-independent reactions, also known as the Calvin cycle, occur in the stroma of chloroplasts. These reactions use the products of the light-dependent reactions (ATP and NADPH) to fix carbon dioxide into organic compounds.

Definition: The Calvin cycle is a series of biochemical reactions that use ATP and NADPH to convert carbon dioxide into glucose.

The Calvin cycle consists of several steps:

  1. Carbon fixation: CO₂ combines with ribulose bisphosphate (RuBP) to form an unstable 6-carbon compound, catalyzed by the enzyme rubisco.

  2. Reduction: The unstable compound is split into two 3-carbon molecules called glycerate-3-phosphate (GP).

  3. Regeneration: GP is reduced to triose phosphate (TP) using ATP and NADPH.

Highlight: The role of ATP and NADPH in photosynthesis is crucial in this stage, providing the energy and reducing power needed to convert CO₂ into sugar.

  1. Synthesis of glucose: Some TP molecules are used to synthesize glucose, while others are recycled to regenerate RuBP.

Example: Out of every six carbon atoms that enter the cycle, one glucose molecule (C₆H₁₂O₆) is produced, while the rest are used to regenerate RuBP.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

Light-Dependent Reactions in Photosynthesis

The light-dependent reaction in photosynthesis is a crucial process that occurs in the thylakoid membrane of chloroplasts. This reaction harnesses light energy to produce ATP and NADPH, which are essential for the subsequent light-independent reactions.

Definition: Light-dependent reactions are the initial stage of photosynthesis where light energy is converted into chemical energy in the form of ATP and NADPH.

The process involves several key steps:

  1. Photoionization of chlorophyll: Light energy excites electrons in photosystem II (PS2), raising them to a higher energy level.

  2. Photolysis of water: The excited electrons from PS2 are replaced by splitting water molecules, releasing oxygen as a byproduct.

Equation: H₂O → O₂ + H⁺ + e⁻

  1. Electron Transport Chain (ETC): Excited electrons move down the ETC, losing energy and pumping H⁺ ions into the thylakoid space.

  2. Chemiosmosis: The proton gradient created by the ETC drives ATP synthesis through ATP synthase.

Vocabulary: Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient.

  1. NADPH Production: Electrons that have passed through the ETC are energized again in photosystem I (PS1) and used to reduce NADP⁺ to NADPH.

Highlight: The light-dependent reaction steps produce two key products: ATP and NADPH, which are crucial for the Calvin cycle in the light-independent reactions.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

View

Limiting Factors and Agricultural Practices in Photosynthesis

Understanding the factors affecting the rate of photosynthesis is crucial for optimizing plant growth and agricultural productivity. The main limiting factors include:

  1. Temperature: Affects enzyme activity and overall metabolic rates.
  2. CO₂ concentration: Influences the rate of carbon fixation in the Calvin cycle.
  3. Light intensity: Determines the rate of light-dependent reactions.

Highlight: These are three of the 7 factors affecting the rate of photosynthesis, with others including water availability, mineral nutrients, leaf color, and leaf age.

Agricultural practices have been developed to overcome these limiting factors:

  1. Using LED lights: Provides optimal light intensity and spectrum for photosynthesis.
  2. Greenhouse cultivation: Allows control over temperature and CO₂ levels.
  3. CO₂ enrichment: Burning fuel to increase CO₂ concentration in greenhouses.

Example: In a practical investigating factors affecting the rate of photosynthesis, students might measure oxygen production under different light intensities or CO₂ concentrations.

Understanding these factors and practices is essential for maximizing crop yields and addressing global food security challenges.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

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Can't find what you're looking for? Explore other subjects.

Knowunity is the #1 education app in five European countries

Knowunity has been named a featured story on Apple and has regularly topped the app store charts in the education category in Germany, Italy, Poland, Switzerland, and the United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the #1 education app in five European countries

4.9+

Average app rating

13 M

Pupils love Knowunity

#1

In education app charts in 11 countries

950 K+

Students have uploaded notes

Still not convinced? See what other students are saying...

iOS User

I love this app so much, I also use it daily. I recommend Knowunity to everyone!!! I went from a D to an A with it :D

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The app is very simple and well designed. So far I have always found everything I was looking for :D

Lena, iOS user

I love this app ❤️ I actually use it every time I study.

View

Photosynthesis for Kids: Light-dependent and Light-independent Reactions
user profile picture

Ruth Knowunity

@knowunity.uk

·

542 Followers

Follow

Photosynthesis for Kids: Light-dependent and Light-independent Reactions

Photosynthesis is a complex process involving light-dependent and light-independent reactions. This summary covers the key steps, components, and factors affecting photosynthesis, with a focus on the light-dependent reactions and their products. It also touches on the Calvin cycle and limiting factors in photosynthesis.

  • Light-dependent reactions occur in thylakoid membranes, producing ATP and NADPH
  • Light-independent reactions (Calvin cycle) use these products to fix carbon dioxide
  • Key components include photosystems, electron transport chain, and ATP synthase
  • Limiting factors include temperature, CO2 concentration, and light intensity
  • Agricultural practices can optimize conditions for photosynthesis

01/10/2022

151

Light-Independent Reactions and the Calvin Cycle

The light-independent reactions, also known as the Calvin cycle, occur in the stroma of chloroplasts. These reactions use the products of the light-dependent reactions (ATP and NADPH) to fix carbon dioxide into organic compounds.

Definition: The Calvin cycle is a series of biochemical reactions that use ATP and NADPH to convert carbon dioxide into glucose.

The Calvin cycle consists of several steps:

  1. Carbon fixation: CO₂ combines with ribulose bisphosphate (RuBP) to form an unstable 6-carbon compound, catalyzed by the enzyme rubisco.

  2. Reduction: The unstable compound is split into two 3-carbon molecules called glycerate-3-phosphate (GP).

  3. Regeneration: GP is reduced to triose phosphate (TP) using ATP and NADPH.

Highlight: The role of ATP and NADPH in photosynthesis is crucial in this stage, providing the energy and reducing power needed to convert CO₂ into sugar.

  1. Synthesis of glucose: Some TP molecules are used to synthesize glucose, while others are recycled to regenerate RuBP.

Example: Out of every six carbon atoms that enter the cycle, one glucose molecule (C₆H₁₂O₆) is produced, while the rest are used to regenerate RuBP.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

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Light-Dependent Reactions in Photosynthesis

The light-dependent reaction in photosynthesis is a crucial process that occurs in the thylakoid membrane of chloroplasts. This reaction harnesses light energy to produce ATP and NADPH, which are essential for the subsequent light-independent reactions.

Definition: Light-dependent reactions are the initial stage of photosynthesis where light energy is converted into chemical energy in the form of ATP and NADPH.

The process involves several key steps:

  1. Photoionization of chlorophyll: Light energy excites electrons in photosystem II (PS2), raising them to a higher energy level.

  2. Photolysis of water: The excited electrons from PS2 are replaced by splitting water molecules, releasing oxygen as a byproduct.

Equation: H₂O → O₂ + H⁺ + e⁻

  1. Electron Transport Chain (ETC): Excited electrons move down the ETC, losing energy and pumping H⁺ ions into the thylakoid space.

  2. Chemiosmosis: The proton gradient created by the ETC drives ATP synthesis through ATP synthase.

Vocabulary: Chemiosmosis is the movement of ions across a selectively permeable membrane, down their electrochemical gradient.

  1. NADPH Production: Electrons that have passed through the ETC are energized again in photosystem I (PS1) and used to reduce NADP⁺ to NADPH.

Highlight: The light-dependent reaction steps produce two key products: ATP and NADPH, which are crucial for the Calvin cycle in the light-independent reactions.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

Register

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Join milions of students

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Limiting Factors and Agricultural Practices in Photosynthesis

Understanding the factors affecting the rate of photosynthesis is crucial for optimizing plant growth and agricultural productivity. The main limiting factors include:

  1. Temperature: Affects enzyme activity and overall metabolic rates.
  2. CO₂ concentration: Influences the rate of carbon fixation in the Calvin cycle.
  3. Light intensity: Determines the rate of light-dependent reactions.

Highlight: These are three of the 7 factors affecting the rate of photosynthesis, with others including water availability, mineral nutrients, leaf color, and leaf age.

Agricultural practices have been developed to overcome these limiting factors:

  1. Using LED lights: Provides optimal light intensity and spectrum for photosynthesis.
  2. Greenhouse cultivation: Allows control over temperature and CO₂ levels.
  3. CO₂ enrichment: Burning fuel to increase CO₂ concentration in greenhouses.

Example: In a practical investigating factors affecting the rate of photosynthesis, students might measure oxygen production under different light intensities or CO₂ concentrations.

Understanding these factors and practices is essential for maximizing crop yields and addressing global food security challenges.

Di
0
3.5 - Evergy transfers in and between organisms.
3.5.1- Photosynthesis.
The Light Dependent Reaction.
to Uses light energy and
water
to

Register

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Can't find what you're looking for? Explore other subjects.

Knowunity is the #1 education app in five European countries

Knowunity has been named a featured story on Apple and has regularly topped the app store charts in the education category in Germany, Italy, Poland, Switzerland, and the United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the #1 education app in five European countries

4.9+

Average app rating

13 M

Pupils love Knowunity

#1

In education app charts in 11 countries

950 K+

Students have uploaded notes

Still not convinced? See what other students are saying...

iOS User

I love this app so much, I also use it daily. I recommend Knowunity to everyone!!! I went from a D to an A with it :D

Philip, iOS User

The app is very simple and well designed. So far I have always found everything I was looking for :D

Lena, iOS user

I love this app ❤️ I actually use it every time I study.