Light dependent or hill reaction - class-XII
Description: light dependent or hill reaction | |
Number of Questions: 57 | |
Created by: Niharika Sharma | |
Tags: mineral nutrition photosynthesis in higher plants photosynthesis botany metabolism, cell respiration, and photosynthesis biology |
The product of the light reaction of photosynthesis which is not common between cyclic and non-cyclic photophosphorylation and is not utilised in the Calvin cycle is
-
O$ _2$
-
ATP
-
$NADPH _2$
-
O$ _2$ and ATP
In cyclic phosphorylation, oxygen is not evolved as the by-product where as, oxygen is evolved as a by-product during non-cyclic phosphorylation. Calvin cycle is the second stage of photosynthesis in which carbon atoms from carbon dioxide are combined, using the energy in ATP and NADPH, to make glucose.
How many quanta of lights are required to evolve one oxygen molecule in photosythesis?
-
Three
-
Eight
-
Four
-
Two
During the light phase of photosynthesis .......... is oxidized and .......... is reduced.
-
$CO _2$ and Water
-
Water and $CO _2$
-
Water and $NADP$
-
$NADPH _2$ and $CO _2$
The light reaction takes place in thylakoid discs. There, water is oxidized and oxygen is released. The hydrogen is accepted by $NADP$ and hence get reduced to $NADPH _2$.
Which of the following process is supported by photolysis?
-
Oxidation
-
Reduction
-
Electroporation
-
Transformation
Photolysis is the process of breakdown of water molecule in the presence of sunlight. It results in the release of oxygen and hydrogen. It is also called as photodecomposition. It occurs during photosynthesis in a series of light-driven oxidation events. In this, water absorbs photons and the energy released during this process drives oxidation processes induced by light.
Which one is not include in photochemical phase
-
Light absorption
-
Photophosphorylation
-
$H _2O$ spliting
-
$CO _2$ reduction
Which statement is correct for given reaction for photosynthesis?
$ 2 H _2 A + CO _2 \xrightarrow []{light} 2A + CH _2 O + H _2 O $
-
$H$ donor is oxidisable substrate
-
$O _2 $ evolve from $H _2 O $ if reducible compound is $H _2 O $
-
Glucose gain its oxygen from $H _2 O $
-
Both A and C
The light reaction of the photosynthesis starts when the chlorophyll loses its electron after absorbing the light. In order to maintain the continuity of the reaction, there is a requirement of an oxidizable substance that can donate its electron to the chlorophyll. Water acts as the electron donor through a process called photolysis of water. In this process, the oxygen is also released as a by-product.
Compensation point refers to the intensity of light at which
-
Rate of respiration = Rate of photosynthesis
-
Rate of respiration > Rate of photosynthesis
-
Rate of respiration < Rate of photosynthesis
-
None of the above is correct
During photosynthesis
-
Both ${ CO } _{ 2 }$ and water get oxidised
-
Both ${ CO } _{ 2 }$ and water get reduced
-
Water is reduced and ${ CO } _{ 2 }$ is oxidised
-
Carbon dioxide get reduced and water get oxidised
Oxidative phosphorylation occurs in respiration and _______ occurs in photosynthesis.
-
Oxidative phosphorylation
-
Reductive phosphorylation
-
Cyclic phosphorylation
-
None of the above
Phosphorylation refers to the process of formation of ATP. During respiration, the oxidation of NADH and FADH$ _{2}$ results in ATP formation, hence called oxidative phosphorylation. In photosynthesis, the photosystem II is involved in cyclic photophosphorylation.
Suppose the interior of the thylakoids (lumen) of isolated chloroplasts were made acidic and then transferred in dark to a $pH = 8$ solution, what would be likely to happen?
-
The isolated chloroplast will make $ATP$
-
The Calvin cycle will be activated
-
Cyclic photophosphorylation will occur
-
The isolated chloroplast will reduce $NADP^+$ to $NADPH + H^+ $
The acidic lumen of the thylakoids will have a higher concentration of H$^{+}$ ions. When these are transferred to basic pH of 8, the H$^{+}$ will tend to move outside due to their concentration gradient, which is higher in the lumen and lower in the surrounding. The thylakoids bear ATP synthases that will use the proton motive force H$^{+}$ ions and will make the ATP. So, an isolated chloroplast is capable of synthesizing the ATP when the lumen is made acidic and the outer medium is made alkaline.
Light reaction or photochemical phase includes
I. light absorption
II. water splitting
III. oxygen release
IV. ATP and NADPH formation
Choose the correct option.
-
I, II and IV
-
I, II and III
-
I, III and IV
-
I, II, III and IV
Light reaction or photochemical phase is called as photophosphorylation or Hill's reaction. It includes non-cyclic phosphorylation and cyclic phosphorylation. During this reaction, the light is absorbed by the chlorophyll and water splits into H$ _2$ and 1/2O$ _2$. Oxygen is released as the byproduct of the reaction along with formation of carbohydrate. Along with oxygen, ATP and NADPH are also formed.
Which of the following events does not occur during the light reaction of photosynthesis?
(2) Reduction of NADPH to NADP+
(3) Evolution of molecular oxygen
(4)Synthesis of assimilatory powers
(5)Conversion of CO$ _2$ to carbohydrates
-
1 and 2 only
-
2 and 5 only
-
2 ,3 and 5 only
-
1, 3 and 4 only
The events occurring in the light reaction of the photosynthesis are:
- Absorption of sunlight by the chlorophyll and release of the electron to the carriers.
- Photolysis of water to provide the electron to the chlorophyll.
- The release of molecular oxygen due to the photolysis of water.
- Assimilatory powers are synthesized in the form of ATP and NADPH
- Reduction of NADP$^{+}$ occurs to form NADPH
Which of the following is not correct regarding light compensation point?
-
This condition occurs usually in evening and morning
-
Net production is equal to respiration consumption
-
Gross production is more than Net production
-
There is no gaseous exchange with environment by plant
- The (light) compensation point is the light intensity on the light curve where the rate of photosynthesis exactly matches the rate of cellular respiration.
- When the rate of photosynthesis equals the rate of respiration or photorespiration, the compensation point occurs.
- The compensation point is reached during early mornings and late evenings.
- Hence This condition occurs usually in evening and morning is not correct regarding light compensation point.
- So, the correct answer is 'Option A'.
The site of light reaction is
-
Granum
-
Stroma
-
Unit membrane
-
Stroma lamellae
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. Thylakoids are arranged in stacks called grana.
The chloroplast matrix is called the stroma and contains enzymes that catalyze the light-independent reactions of photosynthesis. But stroma is not the site for light reactions.
Stromal lamellae connect two or more grana to each other. In this way, the lamellae act as a skeleton of the chloroplast, maintaining efficient distances between the grana, thereby maximizing the overall efficiency of the chloroplast.
Each chloroplast is enclosed by (surrounded) a chloroplast envelope or unit membrane consisting of three layers. Overall the chloroplast envelope is semi-permeable. It is permeable to glucose molecules and certain ions including Fe$^{2+}$and Mg$^{2+}$, and oxygen and carbon dioxide.
In photosynthesis, the energy is transferred in
-
One energy step
-
Small energy steps
-
Large energy steps
-
All of the above
In photosynthesis, energy is transferred in small energy steps. Photosynthesis is the primary energy source for most of the biosphere. Even though photosynthetic light harvesting complexes display great variety in their design and function, many of them are membrane proteins that comprise of pigment antenna arrays, which absorb light and transfer the resulting electronic excitation to a reaction center, which in turn converts this excitation energy to a charge gradient across the membrane and help to synthesise ATP. This energy is utilized in dark phase for synthesizing glucose.
Translocation of sugar in angiosperms occur in the form of
-
Glucose
-
Starch
-
Lactose
-
Sucrose
Translocation is the process of movement of nutrients from leaves to other parts of plant. During the process of photosynthesis, carbohydrates (sugars) specifically sucrose is synthesized in the cytosol of cell and then translocated to other demanding parts of plant. Sucrose is complex, less reactive and energy efficient sugar so, angiosperms and other plants translocate sugar in the form of sucrose.
Light reaction of photosynthesis results in products like
-
Starch and O$ _2$.
-
ADP, NADPH + H$^+$ and electrons.
-
ATP, NADPH + H$^+$ and O$ _2$.
-
Glucose and O$ _2$.
The light reaction takes place in the grana of the chloroplast. This is also known as the cyclic and non-cyclic form of photophosphorylation in which the ATP and NADPH + H$^+$ are produced. In the non-cyclic photophosphorylation, there is splitting of the water molecules which results in the production of oxygen molecule.
ATP formation during photosynthesis is known as
-
Phosphorylation.
-
Photophosphorylation.
-
Oxidative phosphorylation.
-
Substrate level phosphorylation.
Photophosphorylation refers to the use of light energy from photosynthesis to ultimately provide the energy to convert ADP to ATP, thus replenishing the universal energy currency in living things. Light generally provides energy to form the bonds. It is an endothermic reaction.
What percentage of usable radiant energy entering a reaction site of photosynthesis is converted to potential energy _________.
-
10%
-
20%
-
35%
-
42%
In light phase of photosynthesis there is formation of
-
$ATP$
-
$NADPH _2$
-
Both $ATP$ and $NADPH _2$
-
Carbohydrates.
In light-dependent reactions, the energy from sunlight is absorbed by chlorophyll and converted into chemical energy in the form of electron carrier molecules like ATP and NADPH.
Light phase consists of
-
Two photochemical reactions
-
Two photosynthetic units
-
Two chloroplast parts
-
None of the above.
Light phase is also known as a photochemical phase because it is a light dependent phase. During this phase, the formation of high-energy chemical intermediates ATP and NADPH$ _{2}$ takes place. ATP and NADPH$ _{2}$ are the assimilatory power of photosynthesis. Light phase also includes light absorption, water splitting and release of oxygen. Two photosynthetic units called Photosystem I and Photosystem II are also involved in light phase. Light phase consists of two photochemical reactions, i.e. non-cyclic photophosphorylation and cyclic photophosphorylation.
Light reaction of photosynthesis occur in
-
Only absence of light
-
Only presence of light
-
Presence and absence of light
-
Absence of light in maximum intensity
In photosynthesis, the light-dependent reactions take place on the thylakoid membranes. The light-independent reactions take place in the stroma. The thylakoid membrane contains some integral membrane protein complexes that catalyze the light reactions. There are four major protein complexes in the thylakoid membrane Photosystem II (PSII), Cytochrome b6f complex, Photosystem I (PSI), and ATP synthase. These four complexes work together to ultimately create the products ATP and NADPH.
The products of photochemical reaction are
-
$O _2$, ATP and NADPH
-
$O _2$
-
ATP and NADPH
-
Organic compounds especially carbohydrates.
Light reactions of photosynthesis which takes place in thylakoids membranes of chloroplast utilize sunlight and water to produce oxygen, ATP and NADPH.
In photosynthesis light energy is utilized in
-
Converting ATP into ADP
-
Changing CO$ _{2}$ into carbohydrate
-
Converting ADP into ATP
-
All of the above
Photosynthesis is a process in which phosphorylation occurs. Phosphorylation is a process in which phosphate group is added, and in the case of photosynthesis it happens in the presence of light, thus called as 'photophosphorylation'. ADP is converted to ATP, the energy currency as the main product of this process. In photosynthesis, cyclic and non-cyclic photophosphorylation takes place in the light phase and generate ATP and NADPH.
The phenomenon of re-irradiation of absorbed light is called
-
Photoluminescence
-
Chemiluminescence
-
Phosphorescence
-
Fluorescence
Photoluminescence is the phenomenon of light emission after absorption of photons in the form of electromagnetic radiation. Chemiluminescence is the phenomenon of emission of light from a chemical reaction. Phosphorescence is a type of photoluminescence which is related to fluorescence. It does not re-irradiate the absorbed light immediately like fluorescence. Fluorescence is the phenomenon of re-irradiation of light absorbed light or electromagnetic radiation.
Raw materials required for light reactions are
-
ADP and $H _2O$
-
ADP, $H _2O$ and NADP
-
ADP and $NADPH _2$
-
ATP and NADP.
A) ADP and ${ H } _{ 2 }O$ are required in addition to NADP.
C) NADPH is a product of the light reaction.
D) ATP is a product of the light reaction.
So the correct answer is 'ADP, ${ H } _{ 2 }O$ and NADP'.
PS I and PS II occur over
-
Grana of chloroplast
-
Matrix of mitochondria
-
Stroma of chloroplast
-
Inner membrane of mitochondrion
The process that converts light energy into chemical energy takes place in a multi-protein complex called a photosystem. Two types of photosystems are embedded in the thylakoid membrane:- photosystem II ( PSII) and photosystem I (PSI). Each photosystem plays a key role in capturing the energy from sunlight by exciting electrons. These energized electrons are transported by “energy carrier” molecules, which power the light-independent reactions.
How many PGAL molecules would regenerate 15 RuBP
-
30
-
25
-
15
-
20.
Excitation of chlorophyll by light is
-
Exergonic reaction
-
Anabolic reaction
-
Photochemical reaction
-
Photooxidation reaction
The first and foremost step of photosynthesis is the excitation of chlorophyll molecule which occurs with the absorption of light. This reaction is photochemical reaction since involves light and results in chemical change by transfer of electrons. The pigments present in the photosystems absorb photon of light. The photons excite electrons in the chlorophyll which then move through the electron transport chain and results in the production of carbohydrates and energy packets NADPH, ATP with the release of oxygen.
Light reaction of photosynthesis is also called
-
Calvin cycle
-
Hill reaction
-
TCA cycle
-
All of the above
The Hill reaction implies that the light-dependent reaction of photosynthesis is a result of a series of redox reactions and a suitable terminal electron acceptor is required for that reaction to occur. Hence, solar energy is converted to chemical energy by the reduction of NADP to NADPH.
First reaction in photosynthesis is
-
Photolysis of water
-
Excitation of chlorophyll molecules
-
Formation of ATP
-
Fixation of CO$ _2$
During the first stage of photosynthesis, called the light-dependent reaction, sunlight excites the electrons in the chlorophyll pigment. The organism uses this energy to create the energy carrier molecules ATP and NADPH, which are crucial for carbon fixing during the second stage.
How much oxygen is formed from 264 g of $CO _2$ and 216 g of $H _2O$?
-
96 g
-
216 g
-
264 g
-
192 g.
- Moles = Weight in gms/molecular weight
- In same way moles of H2O = 216/18 = 12 moles.
Fluoroscence differs from phosphorescence in being
-
Delayed emission
-
Instant emission
-
Bioluminescence
-
Chemiluminescence
In plants, food formation during photosynthesis takes place
-
In root
-
In leaf
-
In stem
-
In flower
Photosynthesis is the process by which plant utilizes the energy obtained from sunlight to produce glucose from carbon dioxide and water. During this process, oxygen is released as the by product. It takes place in leaf cells. Leaf cells contain chloroplasts. The chloroplasts contain green pigment chlorophyll which prepares the food during photosynthesis.
Red drop and Emerson effect have proved the existence of ______________.
-
Light and dark reactions is photosynthesis
-
Two distinct photo systems is photosynthesis
-
The supply of electrons from oxygen evolving complex
-
Electron transport from water to NDAP$+$ across thylakoids
When sun light hits the chloroplast, then
-
Increase in $pH$ of thylakoid lumen relative to stroma occurs
-
A measurable decreases in $pH$ in the thylakoid lumen relative to stroma occurs
-
A measurable decrease in $pH$ in the stroma relative to thylakoid lumen occurs
-
The $pH$ of both stroma and thylakoid luman becomes equal
When the light hits the chloroplast, the chemiosmotic potential is established by thylakoid membrane. The carriers in the electron transport chain use some of the electron’s energy to actively transport protons from the stroma to the lumen. During photosynthesis, the lumen becomes acidic, as low as pH 4, compared to pH 8 in the stroma. Therefore answer B is correct.
In plants, light-dependent reactions proceed at the
-
cytoplasm
-
stroma
-
plasma membrane
-
thylakoid membrane
In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts. 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.
Choose the correct answer from the alternatives given.
The first step in photosynthesis is
-
formation bf $NADPH _2$
-
photolysis of water
-
formation of ATP
-
excitation of an electron of chlorophyll by a photon of light
During the first stage of photosynthesis, called the light-dependent reaction, sunlight excites the electrons in the chlorophyll pigment. The organism uses this energy to create the energy carrier molecules ATP and NADPH, which are crucial for carbon fixing during the second stage.
Photophosphorylation in chloroplast requires movement of:
-
electrons across the membrane
-
ions across the membrane
-
protons across the membrane
-
electrons and protons across the membrane
Phosphorylation in the electron-transport chain in the mitochondrion.
Choose the correct answer from the alternatives given.
In a plant cell, which of the following pigments participates directly in the light reaction of photosynthesis
-
chlorophyll a
-
chlorophyll b
-
carotenes
-
xanthophylls
Green pigments are located within the chloroplasts of plant. Chlorophyll a can participate directly in light reaction which convert solar energy to chemical energy.
In the light-dependent reactions
-
carbon dioxide is fixed
-
$CO _2$ accepts electrons
-
ATP and NADPH are formed
-
sugar phosphates are formed
The ATP and NADPH from the light-dependent reactions are used to make sugars in the next stage of photosynthesis. The net result of this reaction is the production of 2 ATP and 9 NADPH and the photolysis of water. Light is absorbed and the energy is used to drive electrons from water to generate NADPH and to drive protons across a membrane. These protons return through ATP synthase to make ATP.
When a photosystem absorbs light
-
sugar phosphates are produced
-
electrons are transferred to ATP
-
RuBP accepts electrons
-
light-dependent reactions begin
When photosystem II absorbs light, electrons in the reaction-centre chlorophyll are excited to a higher energy level and are trapped by the primary electron acceptors. Photoexcited electrons travel through the cytochrome b6f complex to photosystem I via an electron transport chain set in the thylakoid membrane. 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.
Assume a thylakoid which is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
-
Splitting of water
-
Absorption of light energy by chlorophyll
-
Flow of electrons from photosystem II to photosystem I
-
Synthesis of ATP
The thylakoid membranes have pigment system, electron transport proteins as well as the ATP synthases. When the transfer of electron down the transport proteins occurs, many H$^{+}$ are transported into the thylakoid lumen from the stroma. This high concentration of H$^{+}$ is then used by the ATP synthases to make ATP by transferring these H$^{+}$ out of the thylakoid lumen in the stroma. The punctured thylakoid will not have an intact thylakoid lumen, so the concentration of the H$^{+}$ ins will not be developed. As a result, ATP synthase will not function and so ATP will not be synthesized.
The function of light in photosynthesis is
-
photolysis of water
-
assimilation of carbon dioxide
-
production of organic food
-
activation of enzymes
Synthesis of an assimilatory power takes place in _____________ phase of photosynthesis.
-
Light phase
-
Dark phase
-
Glycolysis
-
All the above
Which statement are not true for photosynthesis?
-
$CO _2$ reduction occur in dark reaction
-
$H _2O$ oxidation occur in light reaction
-
Light reaction is an enzymatic phase of photosynthesis
-
Dark reaction may occur in dark if light reaction products are available there
The overall function of light-dependent reactions is to capture the energy from the light for the generation of ATP and NADPH molecules. The dark reactions of the C$ _{3}$ cycle utilize the energy from short-lived electronically excited carriers to convert CO$ _{2}$ & H$ _{2}$O into glucose catalyzed by the enzyme RuBisCo, and this constitutes carbon fixation and makes it the enzymatic phase.
Which one is not included in photochemical phase?
-
Light absorption
-
Photosphorylation
-
${ H } _{ 2 }O$ splitting
-
${ CO } _{ 2 }$ reduction
- The photochemical step is dependent upon light, therefore it is also called as Light or Hill reaction. It involves the following reactions:
- Photolysis of water: It is the phenomenon of breaking up of water into hydrogen and oxygen in the illuminated chloroplasts
- Production of assimilatory power: While passing over cytochrome complex, the electron loses sufficient energy for the creation of proton gradient and synthesis of ATP from ADP and inorganic phosphate. The process is called photophosphorylation
- So, the correct option is 'CO2 reduction'.
Chlorophylls absorb visible light of wavelengths
-
400-500 nm only
-
300-400 nm only
-
600-800 nm only
-
400-500 nm and 600-700 nm.
Chlorophyll present in the plants can absorb the the wavelength of both blue and red regions of VIBGYOR which ranges from 400-500 nm and 600-700 nm respectively. It reflects the green light range of 500-600 nm hence the leaves appear green.
Which one directly transfers electrons to $NADP^+$ during light reaction?
-
PS I
-
PS II
-
Cytochromes
-
Plastocyanin.
The light-dependent reactions start in photosystem II (PSII). When the pigment in the reaction centre of PS II i.e, P$ _{680}$ absorbs a photon, an electron in this molecule gets excited and transferred to a primary electron acceptor, Pheophytin and then go through molecules in a series of redox. The electron flow goes from PSII to cytochrome b6f complex than to PSI. In PSI, the electron is finally accepted by NADP. Thus photosystem I in light-dependent reaction directly transfers electrons to NADP.
Light energy is converted into chemical energy through the formation of
-
$NADPH _2$
-
$ATP$
-
$ATP$ and $NADPH _2$
-
None of the above.
In the light reactions of photosynthesis,
-
PS I produces strong oxidant while PS II a strong reductant.
-
PS I produces strong reductant $NADPH$ while PS II a strong oxidant.
-
PS I emits electrons for PS II.
-
PS I produces ATP which is not formed by PS II.
PS I: This system produces a strong reductant which reduces ${NADP}^+$ to $NADPH$.
Photosynthesis is considered as an oxidation reaction, because
-
$CO _2$ is oxidised
-
$H _2O$ is oxidised
-
$O _2$ is released
-
$(CH _2O)$ is oxidised.
A) Carbon dioxide is reduced, not oxidised.
B) Water is oxidised to form protons and release oxygen. ${ H } _{ 2 }O\longrightarrow { O } _{ 2 }+{ 2H }^{ + }$
D) ${ CH } _{ 2 }O$ does not undergo oxidation.
So the correct answer is '${ H } _{ 2 }O$ is oxidised'.
-
approximates the action spectrum of photosynthesis
-
shows that some colours of light are absorbed more than others
-
explains why chlorophyll is a green pigment
-
all of the above are correct
Green plants are green because they contain a pigment called chlorophyll as in the absorption spectra, chlorophyll absorbs light in the red (long wavelength) and the blue (short wavelength) regions of the visible light spectrum. The green light is not absorbed but reflected, making the plant appear green. An absorption spectrum shows all the light typically absorbed by a leaf. An action spectrum, meanwhile, shows all the light that is actually used for photosynthesis. The similarity of the action spectrum of photosynthesis and the absorption spectrum of chlorophyll tells us that chlorophyll is the most important pigments in the process. The spectra are not identical, though, because carotenoid, which absorbs strongly in the blue, play a role as well.
Hill used a dye for his famous hill reaction is
-
Sulphur green
-
Eosine
-
Methylene blue
-
Dichlorophenol indophenol
In the year 1937 and 1939, Robert hill studied the light dependent reaction and revealed that oxygen evolved during photosynthesis came from water. In his experiment, he used Dichlorophenolindophenol (DCPIP) as a redox dye to measure the rate of photosynthesis. The dye is blue in oxidized state with a maximal absorption at 600 nm whereas in reduced, DCPIP is colourless.
Choose the correct answer from the alternatives given.
NADPH and ATP from the light-dependent reactions are used to
-
cause rubisco to fix $CO _2$
-
cause electrons to move along their pathways
-
reform the photosystems
-
convert PGA to PGAL
Which one is directly involved in light reaction of photosynthesis
-
Chlorophyll a
-
Chlorophyll b
-
Carotenoids
-
All the above.
Photosynthesis takes place in the green leaves of plants and other green part of plants like stem etc. The most active photosynthetic tissue in higher plants is the mesophyll of leaves. Mesophyll cells have many chloroplasts, which contain the specialised light absorbing green pigments, the chlorophylls. When chlorophyll absorbs light, it gets excited and emits electrons. Chlorophyll a is the primary photosynthetic pigment. It shows bright or blue green colour in chromatogram. Chlorophyll a is directly involved in light reaction of photosynthesis. It is present in the reaction centres of Photosystem I and Photosystem II which absorbs light energy of longer wavelength. These centres can release electron upon absorption of energy.
When chlorophyll absorbs light, it gets excited and emits (releases)
-
Oxygen
-
Water
-
Electrons
-
Energy rich compounds.
Photosynthesis takes place in the green leaves of plants and other green parts of plants like stem etc. When chlorophyll absorbs light, it gets excited and emits electrons. These chlorophylls are found in photosynthetic units called Photosystem I and Photosystem II. Each unit has a specific reaction center which contains pigment molecules. These molecules absorb light of different wavelengths and emit electrons. These electrons are picked up by an electron acceptor which passes them to an electron transport system of cytochromes.