... chlorophyll molecule which results in their excitation to higher energy levels. Thereafter,
electrons from the excited chlorophyll molecules are transferred to specialized acceptor
molecule and ultimately to NADP+ which is accompanied by ATP formation. Water serves as edonor (reducing agent) purpose ...
... • Light-dependent reaction: takes place in the thylakoid space and
across the thylakoid membranes.
• Light-independent reaction: takes place in the stroma.
... F. 2 Different Reactions
1. Light Dependent Reactions
Capture light energy for photosynthesis
Use sunlight to make ATP and NADPH
In thylakoid membranes of chloroplast
H2O is a substrate provides electrons and hydrogen ions
O2 is a product of this reaction
... antenna pigments transferring energy to each reaction centre. Plants found in full sunlight will tend
to have antennae with fewer pigments. If the amount of light that is absorbed by plants exceeds
their capacity for electron transfer, part of the photosynthetic electron transfer chain can be shut
Bacterial Reaction Centers overall reaction Interesting questions
... UQ(ox) + 2e +H --> UQH2 (red) Em = 60 mV
-[cyt c(ox) + e = cyt c(red)]
∆G° = -n∆E°= 60 + -2(250) = +440 meV
This is fueled by 2 photon of 860 nM (1246.4 eV/860=1.44 eV/photon)
efficiency = (440 meV out)/(2.88 meV in)=15%
You can also highlight the individual reactions along the pathway r ...
SBI 4U photosynthesis 1
... are transferred one by one along a series
of eletron-carrying molecules (electron
Each transfer of electrons releases a small
amount of energy
Energy is used by a b6-f complex to pump
hydrogen ions form the stroma across the
This creates an electrochemical ...
... energy into the potential chemical energy found between the
carbon, hydrogen, and oxygen bonds in sugar (glucose).
1. Photosynthesis uses most of the energy in sunlight except
green wavelengths (color that's reflected)
2. The light reactions occur on thylakoid membranes in plants
(similar membranes ...
... a) When light is absorbed by chlorophyll, some of its electrons become excited and leap out of the chlorophyll molecule,
grabbed by energy receptors.
b) The energy of these electrons is used to make ATP from ADP + Pi
•a) When light is absorbed by chlorophyll, some of its electrons become ...
... H2O + light energy ---> ½ O2 + 2H+ + 2 electrons
Excited electrons from Photosystem I can use an electron transport chain to reduce oxidized P700. This sets up a proton gradient, which can generate ATP. The end result of this looping
electron flow, called cyclic phosphorylation, is the generation of ...
BCH 413- PLANT BIOCHEMISTRY (2 UNITS) • ORGANIZATION OF
... 1. Excited electrons from Photosystem I can use an electron transport chain to reduce oxidized P700.
This sets up a proton gradient, which can generate ATP. The end result of this looping electron
flow, called cyclic phosphorylation, is the generation of ATP and P700.
2. Excited electrons from Phot ...
Photosyn online lab
... up at the end of photosynthesis? What happens to the oxygen that was in the water molecule?
CHO O HO COOH OH O
... Chlorophyll fluorescence dumps
excess energy from absorbed light
Ch 6-1 Notes
... 3. The electrons are then transferred along a
series of molecules called an electron
Photosynthesis - Weizmann Institute of Science
... In the light-dependent reactions the pigment chlorophyll absorbs light and loses an
electron that travels down an electron transport chain producing the high energy
molecules NADPH and ATP. The chlorophyll molecule regains its electron by taking
one from water, which results in releasing oxygen gas. ...
During the light reactions, there are two possible routes of electron
... Note: ATP synthesis occurs through photophosphorylation (light-dependent
formation of ATP by chemiosmosis)
1. A photon strikes photosystem II and excites an electron of P680 (chlorophyll a of
photosystem II). The excited electron is then captured by the primary electron
acceptor. This pro ...
Photosynthesis: How Do Organisms Get Energy From the Sun?
... Photosystem II uses P680
The electrons from P 680 go into their own
electron transport chain where ATP is
produced by noncyclic photophosphorylation.
The final electron acceptor is P700.
But now P680 is oxidized. Where can it get
... c. permit the passage of substances
(e.g., ions) between cells through small
passageways that directly link the
cytoplasm of one cell to the cytoplasm
of another cell
d. None of these are correct.
1 - contentextra
... are de-energized through an electron transport chain to produce ATP and free hydrogens.
Photosystem I then occurs with the formation of NADPH.
12 ATP and NADPH from the light-dependent reaction then pass to the light-independent reaction.
The light-independent reaction then occurs within the stroma ...
You are Star-stuff, But You Can`t Eat Photons
... harnessed by molecular machinery surrounding the photosynthetic center, and helps to create a voltage
drop across a special membrane, much like a battery recharging by forming a voltage across its two
terminals. Once the electron reaches the end of its journey, it is contained in a molecule called N ...
Photosynthetic reaction centre
A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors assembled together to execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and phaeophytin, as well as quinones. The energy of the photon is used to promote an electron to a higher molecular energy level of a pigment. The free energy created is then used to reduce a chain of nearby electron acceptors, which have subsequently higher redox-potentials. These electron transfer steps are the initial phase of a series of energy conversion reactions, ultimately resulting in the production of chemical energy during photosynthesis.