What Are Light Independent Reactions


Table of Contents

Which is a light independent reaction?

The light-independent reactions (Calvin cycle) use stored chemical energy from the light-dependent reactions to “fix” CO2 and create a product that can be converted into glucose. The ultimate goal of the light-independent reactions (or Calvin cycle) is to assemble a molecule of glucose.

What is light dependent and independent reactions?

In the light-dependent reactions energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy. In the light-independent reactions the chemical energy harvested during the light-dependent reactions drives the assembly of sugar molecules from carbon dioxide.

What are the light independent processes?

The light independent process (also called dark reactions or the Calvin-Benson cycle) takes place in the stroma of the chloroplast. Carbon dioxide is modified by series of chemical reactions to form carbohydrates. The energy for these reactions comes from ATP and NADPH generated during the light dependent process.

What are 3 characteristics of light-independent reactions?

The light-independent reactions of the Calvin cycle can be organized into three basic stages: fixation reduction and regeneration.

Why is it called the light independent reaction?

These reactions are also called the light-independent reactions because they are not directly driven by light. In the Calvin cycle carbon atoms from CO2​start text C O end text start subscript 2 end subscript are fixed (incorporated into organic molecules) and used to build three-carbon sugars.

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Does light-independent reaction require light?

The light-independent reactions are sometimes called the Calvin cycle because of the cyclical nature of the process. Although the light-independent reactions do not use light as a reactant (and as a result can take place at day or night) they require the products of the light-dependent reactions to function.

What are the 3 reactants of light-dependent reactions?

The reactants in the light-dependent chemical reaction are adenosine diphosphate (ADP) oxydized nicotinamide adenine dinucleotide phosphate (NADP+) and the hydrogen in water.

What does light dependent reaction use?

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.

Is oxygen light dependent or independent?

Explanation: Oxygen is in fact a by product of light dependent reactions of photosynthesis.

What are the end products of the light independent reaction?

4.68. 5.1 Photosynthesis
Light treatment Respiration (μmol CO2 m2 s1) Photosynthetic max (μmol CO2 m2 s1)
Red-Blue LED −2.07(0.20) 20.83(1.19)
Red-White LED −1.82(0.09) 19.79(1.32)
Red LED −1.79(0.35) 15.90(0.35)
Blue LED −1.29(0.11) 14.45(0.78)

Where does light dependent reaction occur?

Light-dependent reactions happen in the thylakoid membrane of the chloroplasts and occur in the presence of sunlight. The sunlight is converted to chemical energy during these reactions. The chlorophyll in the plants absorb sunlight and transfers to the photosystem which are responsible for photosynthesis.

What is required for a light-independent reaction?

The requirements or ingredients for light-independent reactions are carbon dioxide and energy in the form of ATP and NADPH.

Can light-independent reactions occur in the dark?

There are three phases to the light-independent reactions collectively called the Calvin cycle: carboxylation reduction reactions and ribulose 1 5-bisphosphate (RuBP) regeneration. Though it is called the “dark reaction” the Calvin cycle does not actually occur in the dark or during night time.

Is stroma light-dependent?

In photosynthesis the light-dependent reactions take place on the thylakoid membranes. The inside of the thylakoid membrane is called the lumen and outside the thylakoid membrane is the stroma where the light-independent reactions take place.

What is the light-dependent reaction equation?

The light-dependent reactions can be summarized as follows: 12 H2O + 12 NADP+ + 18 ADP + 18 Pi + light and chlorophyll yields 6 O2 + 12 NADPH + 18 ATP.

Is the Calvin cycle light-dependent?

The Calvin cycle refers to the light-independent reactions in photosynthesis that take place in three key steps. Although the Calvin Cycle is not directly dependent on light it is indirectly dependent on light since the necessary energy carriers (ATP and NADPH) are products of light-dependent reactions.

Is Sugars light-dependent or independent?

In photosynthesis a light-independent reaction takes place in plant chloroplasts. In this process sugars are made from carbon dioxide. The process known as the Calvin cycle uses products of the light-dependent reactions (ATP and NADPH) and various enzymes.

Is water light-Dependent?

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 is broken apart.

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Is water a light-dependent reaction?

In photosynthesis a light-dependent reaction uses light energy from the sun to split water which has been taken in by the organism. Water when split gives oxygen hydrogen and electrons. … The hydrogen is converted to NADPH which is then used in the light-independent reactions.

What is light independent reaction often called?

Other names for light-independent reactions include the Calvin cycle the Calvin-Benson cycle and dark reactions. … These energy-carrying molecules are made in the stroma where the Calvin cycle takes place.

Why should the light-dependent reaction occurs before the light-independent reaction?

In light – dependent photosynthesis the photosynthetic pigment absorbs the light energy and convert it into chemical energy ATP and NADPH2 . … So the light-dependent reaction should occur before the light-independent reaction.

What does light-dependent reactions mean in biology?

Light-dependent reaction (biology definition): the series of biochemical reactions in photosynthesis requiring light energy that is captured by light-absorbing pigments (such as chlorophyll) to be converted into chemical energy (ATP and NADPH).

Can Light independent reactions occur without the light dependent reactions?

The light dependent reactions of photosynthesis produce energy in the form of ATP and the electron carrier molecule NADPH which are needed for the light independent reactions. If the light dependent reactions are stopped there will be no ATP and NADPH for the light independent reactions and the plant will die.

Does light-independent reaction occur only at night?

Many students believe that the light-dependent reactions occur in the daytime and the light-independent reactions (sometimes called the “dark” reactions) occur at night when the plant can’t get sunlight so it needs sugar. … But all eukaryotes including plants carry out cellular respiration.

What is ADP and NADP?

ATP – Adenosine triphosphate. ADP – Adenosine diphosphate. NADP – Nicotinamide adenine dinucleotide phosphate. NADPH – The reduced form of NADP. In the Light Dependent Processes i.e Light Reactions the light strikes chlorophyll a in such a way as to excite electrons to a higher energy state.

What is the difference between NADP and NADPH?

Nicotinamide adenine dinucleotide phosphate or NADP+ is a similar molecule with a similar function differing from NAD+ in that it contains an additional phosphate group. The oxidized form is NADP+ while the reduced form is NADPH.

What are grana and stroma?

Grana and stroma are two structures of chloroplast. Grana are the stacks of thylakoids where light reaction of photosynthesis takes place. Stroma is the jell-like matrix of the chloroplast which contains the enzymes for dark reaction of photosynthesis.

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What products of the light dependent reactions are used in the light-independent reactions?

Figure 8.6. 1: The light-dependent reactions of photosynthesis (left) convert light energy into chemical energy forming ATP and NADPH. These products are used by the light-independent reactions to fix CO2 producing organic carbon molecules.

What is required for both the light dependent and light-independent reactions to proceed?

Light dependent reactions occur in Grana of Chloroplasts Light Independent reactions occur in Stroma of Chloroplasts. Hence Chloroplasts are required for both the light-dependent and light-independent reactions to proceed. Elaine C. The answer is energy.

What was produced during the light independent reaction or Calvin cycle?

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.

What two products of light reactions are used up?

What two products of the light reactions are used up in the calvin cycle? NADPH which is an electron carrier and can be reused and ATP or ADP which is an energy molecule that can be rebuilt in another light reaction.

What are the products of light reactions?

What are the products of light reactions and how are they used? The products are ATP and NADPH and oxygen. ATP and NADPH supply energy for carbon fixation in the Calvin cycle . Oxygen is released into the atmosphere.

What provides electrons for the light reactions?

Light reactions occur when plants synthesize food from carbon dioxide and water referring specifically to the part of energy production that requires light and water to generate electrons needed for further synthesis. Water provides the electrons by splitting into hydrogen and oxygen atoms.

Why does light reactions precede dark reaction during photosynthesis?

Light provides energy for the synthesis of glucose from carbon dioxide and water during photosynthesis. … Thus light reaction must precede dark reaction. During light reaction the chlorophyll entraps light and the solar energy is converted into chemical energy in the form of ATP molecules.

The Calvin Cycle

The Light Independent Reaction of Photosynthesis

Photosynthesis: Light-dependent/independent reactions

Photosynthesis: Light Reaction Calvin Cycle and Electron Transport

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