Each step pushes molecules uphill in terms of energy content. Recall that in the electron transport chain,
excited electrons lose energy to NADPH and ATP
. In the Calvin cycle, NADPH and ATP formed in the light reactions lose their stored chemical energy to build glucose.
Can ATP donate electrons?
| Stage Direct products (net) Ultimate ATP yield (net) | Pyruvate oxidation 2 NADH 5 ATP | Citric acid cycle 2 ATP/GTP 2 ATP | 6 NADH 15 ATP | 2 FADH 2 3 ATP |
|---|
Does the Calvin cycle convert ATP?
The resulting six-carbon compound is broken down into two three-carbon compounds, and
the energy in ATP and NADPH is used to convert these molecules into G3P
. One of the three-carbon molecules of G3P leaves the cycle to become a part of a carbohydrate molecule.
What is reduced in the Calvin cycle?
In the Calvin cycle, the ATP made in the light reaction provides the energy and the NADPH provides the reducing power needed to make sugar from
carbon dioxide
and water. Carbon dioxide is reduced into G3P.
What happens during the reduction stage of the Calvin cycle?
In the second stage of the Calvin cycle,
the 3-PGA molecules created through carbon fixation are converted into molecules of a simple sugar – glyceraldehyde-3 phosphate (G3P)
. … This step is called “reduction” because NADPH donates electrons to the 3-phosphoglyceric acid molecules to create glyceraldehyde-3 phosphate.
Why is ATP needed in the Calvin cycle?
ATP and NADPH produced by the light reactions are used in the Calvin cycle
to reduce carbon dioxide to sugar
. The Calvin cycle is similar to the Krebs cycle in that the starting material is regenerated by the end of the cycle. Carbon enters the Calvin cycle as CO2 and leaves as sugar.
How is ATP made during the light reactions?
In a process called non-cyclic photophosphorylation (the “standard” form of the light-dependent reactions),
electrons are removed from water and passed through PSII and PSI before ending up in NADPH
. This process requires light to be absorbed twice, once in each photosystem, and it makes ATP .
What happens to CO2 in Calvin cycle?
In the Calvin cycle,
carbon dioxide molecules (CO2) are combined with each other and with the electrons and Hydrogen ions from NADPH to form glucose
(C6H12O6).
Is any ATP used in the electron transport chain?
No ATP is produced in the electron transport chain
. Is any ATP used in the electron transport chain? No, the electrons provide energy. Describe the movement of hydrogen ions through the membrane.
What is the role of electrons in the electron transport chain?
In the electron transport chain, electrons are used
to release energy, develop a chemical gradient, and form an electrochemical gradient that is finally used to produce ATP molecules
.
How is ATP produced in the electron transport chain?
The process of forming ATP from the electron transport chain is known as
oxidative phosphorylation
. Electrons carried by NADH + H
+
and FADH
2
are transferred to oxygen via a series of electron carriers, and ATPs are formed. Three ATPs are formed from each NADH + H
+
, and two ATPs are formed for each FADH
2
in eukaryotes.
Which stage of the Calvin cycle utilizes ATP?
In stage 3, RuBP, the molecule that starts the cycle, is regenerated so that the cycle can continue.
Stage 2
utilises ATP for incorporation into PGA and NADPH+ is reduced into NADP+ to form G-3-P.
What transports electrons from the light reactions to the Calvin cycle?
What transports electrons from the light reactions to the Calvin cycle?
NADPH is an electron carrier
that picks up electrons in the light reactions and releases them in the Calvin cycle.
Why does it take three turns of the Calvin cycle to produce G3P?
Why does it take three turns of the Calvin cycle to produce G3P, the initial product of photosynthesis?
Because G3P has three carbon atoms, and each turn of the cycle takes in one carbon atom in the form of carbon dioxide
.
Is ATP reduced or oxidized in the Calvin cycle?
Phase II: Reduction.
In the second phase, reduction,
PGA is reduced to G3P (glyceraldehye 3-phosphate) using ATP and NADPH
. Some G3P (which has three carbons) leaves the Calvin cycle and is converted to glucose and other sugars.
Which of these phosphorylates ADP to ATP?
ATP synthase
phosphorylates ADP. Which of these phosphorylates ADP to make ATP? The energy released as electrons are passed along the electron transport chain is used to pump protons into the thylakoid compartment.
What is the end product of the Calvin cycle?
The reactions of the Calvin cycle add carbon (from carbon dioxide in the atmosphere) to a simple five-carbon molecule called RuBP. The Calvin cycle reactions use chemical energy from NADPH and ATP that were produced in the light reactions. The final product of the Calvin cycle is
glucose
.
What is one role of ATP in the light independent reaction of photosynthesis?
What is one role of ATP in the light-independent reaction of photosynthesis? ATP
supplies the energy to produce glucose and other carbohydrates
.
Why are ATP and NADPH important in the Calvin cycle?
ATP and NADPH are
used to convert the six molecules of 3-PGA into six molecules of a chemical called glyceraldehyde 3-phosphate (G3P)
. This is a reduction reaction because it involves the gain of electrons by 3-PGA. Recall that a reduction is the gain of an electron by an atom or molecule.
What are the roles of ATP and NADPH in photosynthesis?
So in summary, there are two main roles of NADPH and ATP: (1)
they tie the light dependent reactions and the light independent reactions together
and (2) they act as sources of energy to take the energy from the sun to the light independent reactions to make the plants food.
How many ATP and nadph2 molecules are required for Calvin cycle?
The Calvin cycle uses
18 ATP and 12 NADPH molecules
to produce one glucose molecule.
What is the most important result of the Calvin cycle?
What is the most important result of the Calvin Cycle?
The ‘fixing' of CO2 to yield two molecules of PGAL. Cycle
.
What happens to the ADP and NADP+ produced by the Calvin cycle?
The Calvin cycle converts ATP to ADP and Pi, and it
converts NADPH to NADP+
. The ADP, Pi, and NADP+ can be reused as substrates in the light reactions.
Is ATP produced by light?
In the light reactions, energy from sunlight drives the synthesis of ATP and NADPH
, coupled to the formation of O
2
from H
2
O. In the dark reactions, so named because they do not require sunlight, the ATP and NADPH produced by the light reactions drive glucose synthesis.
How then is ATP produced by cyclic electron flow?
In cyclic electron flow (CEF), electrons are recycled around photosystem I. As a result,
a transthylakoid proton gradient (ΔpH) is generated
, leading to the production of ATP without concomitant production of NADPH, thus increasing the ATP/NADPH ratio within the chloroplast.
Is ATP produced in photosynthesis?
The ATP is produced during the light reaction of photosynthesis by photophosphorylation
. ATPs are produced towards the stromal side of the thylakoid membrane. The light energy is absorbed and stored in the high energy compounds, namely, ATP and NADPH.
