Name: ________________________________ Period: ____________ Date: _______________________
Biology
8-3 The Reactions of Photosynthesis
Inside a Chloroplast
Inside a Chloroplast
In plants, ___________________ takes place inside _______________________.
Plant
Chloroplast
Plant cells
Inside a Chloroplast
Chloroplasts contain _____________________—saclike photosynthetic membranes.
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Inside a Chloroplast
___________________are arranged in stacks known as ____________. A singular stack is called a
_____________.
Inside a Chloroplast
__________________in the thylakoid membrane organize ______________________ and other
pigments into clusters called________________________, which are the light-collecting units of
the chloroplast.
Inside a Chloroplast
The reactions of photosystems include: the ______- _____________ reactions and the lightindependent reactions, or _____________ ______________.
The light-dependent ________________ take place within the __________________membranes.
The Calvin cycle takes place in the_______________, which is the region outside the thylakoid
________________________.
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Inside a Chloroplast
Electron Carriers
When electrons in chlorophyll ________________sunlight, the electrons gain a great deal of
____________________.
Cells use electron __________________ to _______________________ these high-energy electrons
from chlorophyll to other molecules.
Electron Carriers
One carrier molecule is ________________.
_______________________ carriers, such as , ___________________, transport electrons.
NADP+ accepts and holds ____ ________ - _____________ _____________along with a hydrogen
ion (H+). This converts the NADP+ into _______________.
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Electron Carriers
The conversion of _____________ into ________________ is one way some of the energy of
sunlight can be trapped in _____________ form.
The NADPH carries high-energy _________________ to chemical reactions elsewhere in the
cell.
These _________ - ____________ electrons are used to help build a variety of molecules the
cell needs, including _____________________ like ___________________.
Light-Dependent Reactions
What happens in the light-dependent reactions?
Light-Dependent Reactions
The light-dependent reactions require ____________.
The light-dependent reactions produce _____________ gas and convert ADP and NADP+ into
the energy carriers ________ and ____________.
Light-Dependent Reactions
Light-Dependent Reactions
Photosynthesis begins when pigments in _____________________ absorb light, increasing their
energy level.
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Light-Dependent Reactions
These high-energy electrons are passed on to the___________________ ___________________
______________________.
Light-Dependent Reactions
________________________ on the thylakoid _________________ break water molecules into:
a.
b.
c.
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Light-Dependent Reactions
The light-dependent reactions use ______________, ______________, and ________________.
The light-dependent reactions produce __________________, _________, and
____________________.
These compounds provide the energy to build energy-containing ________________ from lowenergy compounds.
The Calvin Cycle
What is the Calvin cycle?
The Calvin Cycle
________ and ___________ formed by the ______________ - _______________reactions contain
an abundance of chemical energy, but they are not stable enough to store that energy for
more than a few minutes.
During the ______________ ____________ plants use the energy that _________ and ___________
contain to build high-energy compounds that can be stored for a long time.
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The Calvin Cycle
The Calvin cycle uses __________ and ___________ from the ___________ - ________________
reactions to produce high-energy ______________.
Because the ______________ _______________ does not require ________________, these
reactions are also called the light-independent reactions.
The Calvin Cycle
Six ______________________ ____________________ molecules enter the cycle from the
_____________________________ and combine with six 5-carbon molecules.
The Calvin Cycle
The result is _______________ 3-carbon molecules, which are then converted into higherenergy forms.
The energy for this conversion comes from ________________ and high-energy electrons from
___________________________.
______________ of twelve 3-carbon molecules are removed from the cycle.
The molecules are used to produce ___________________.
The 10 remaining 3-carbon molecules are converted back into ______________ 5-carbon
molecules, which are used to begin the next cycle.
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The Calvin Cycle
The two sets of _____________________________ reactions work together.
The light-dependent reactions trap sunlight _____________ in _____________________ form.
The light-independent reactions use that __________________________ energy to produce
stable, high-energy ________________ from _______________ ____________ and _______________.
Factors Affecting Photosynthesis
Many factors affect the ________________ of ____________________________, including:
a.
b.
c.
QUIZ 8-3
_____ 1. In plants, photosynthesis takes place inside the
a. thylakoids.
b. chloroplasts.
c. photosystems.
d. chlorophyll.
_____ 2. Energy to make ATP in the chloroplast comes most directly from
a. hydrogen ions flowing through an enzyme in the thylakoid membrane.
b. transfer of a phosphate from ADP.
c. electrons moving through the electron transport chain.
d. electrons transferred directly from NADPH.
_____ 3. NADPH is produced in light-dependent reactions and carries energy in the form of
a. ATP.
b. high-energy electrons.
c. low-energy electrons.
d. ADP.
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_____ 4. What is another name for the Calvin cycle?
a. light-dependent reactions
b. light-independent reactions
c. electron transport chain
d. photosynthesis
_____ 5. Which of the following factors does NOT directly affect photosynthesis?
a. wind
b. water supply
c. temperature
d. light intensity
END OF SECTION
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