Cellular Energy
chapter
8
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
-!). )DEA
Light energy is trapped and
converted into chemical energy
during photosynthesis

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

.
What Y

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

ou’ll Learn

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

■ the two phases of photosynthesis

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

■ how a chloroplast works during

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

light reactions

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

■ how electron transport works

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

Before You Read
Plants change energy from sunlight into energy that is used by
other living things. Describe on the lines below what would
happen to life on Earth if plants suddenly disappeared. Then
read about how plants use the Sun’s energy.
Identify Details As you
read, highlight or underline
the events of each stage of
photosynthesis.
1. Identify one way cells
can use glucose.
section ● Photosynthesis
2
Read to Learn
Overview of Photosynthesis

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

Photosynthesis is the process in which light energy from
the Sun is changed into chemical energy. Nearly all life on
Earth depends on photosynthesis. The chemical equation for
photosynthesis is shown below.
6CO2 ⫹ 6H2O C
6H12O6 ⫹ 6O2
Photosynthesis occurs in two phases. In phase one—the
light-dependent reactions—light energ

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

y is absorbed and

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png
changed into c

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

hemical energ

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

y in the form of

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

 ATP and
NADPH.

nadph : An electron carrier that provides the high-energy electrons required to store energy in the light-independent reactions of photosynthesis.

Image_nadph_0.png

In phase two—the light-independent reactions—the ATP
and NADPH that were formed in phase one are used to
make glucose. Glucose can then be joined with other simple
sugars to form larger molecules such as complex sugars
and carbohydrates. Sugar can also be changed into other
molecules needed by the cell, such as proteins, lipids, and
nucleic acids.
light
86
Chapter 8 Cellular Energy Reading Essentials
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Phase One: Light Reactions

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

Plants have special organelles called chloroplasts

role of chloroplasts : Chloroplasts are the organelles in plants that capture sunlight and initiate photosynthesis. They contain thylakoids, grana, and stroma where different phases of photosynthesis occur.

Image_role-of-chloroplasts_0.png

 to
capture light energy. Photosynthesi

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

s begins when sunlight
is captured. The captured energy is stored in two energy
storage molecules—A

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

TP

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

 and NADPH—that will be used
in light-independent reactions.
What happens in chloroplasts?
Chloroplasts are large organelles that capture light
energy from the Sun. They are found in plants and other
photosynthetic organisms. The fi gure below shows
a chloroplast.
A chloroplast is a disc-shaped organelle that contains two
compartments. Thylakoids (THI la koyds) are fl attened
saclike membranes. The thylakoids are arranged in stacks
called grana. The fl uid-fi lled space outside the grana is the
stroma

stroma : The fluid-filled space inside the chloroplast surrounding thylakoid stacks where light-independent reactions occur.

Image_stroma_0.png

. Phase one t

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

akes place in t

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

he t

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

hylakoid

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

s. Phase two
takes place in the stroma.
2. Name Which organism
has chloroplasts? (Circle
your answer.)
a. mushroom
b. oak tree
c. earthworm
Picture This
3. Illustrate In the box,
draw an enlarged picture
of a granum

granum : A stack of thylakoids in the chloroplast, involved in the light reactions of photosynthesis.

Image_granum_0.png

.
4. Explain Why do the
leaves of some trees
change colors in autumn?
Granum
Thylakoid

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

 Location of
phase one
Stroma

stroma : The fluid-filled space inside the chloroplast surrounding thylakoid stacks where light-independent reactions occur.

Image_stroma_0.png

—
location of
phase two
Outer
membrane
Inner
membrane
Chloroplas

role of chloroplasts : Chloroplasts are the organelles in plants that capture sunlight and initiate photosynthesis. They contain thylakoids, grana, and stroma where different phases of photosynthesis occur.

Image_role-of-chloroplasts_0.png

chlorophyll : The green pigment in plants that absorbs light energy necessary for photosynthesis.

Image_chlorophyll_0.png

t
What is the role of pigments in photosynthesis

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

?
Thylakoids contain light-absorbing colored molecules known
as pigments. Different pigments absorb different wavelengths
of light. Chlorophylls are the major light-absorbing pigments
in plants. They absorb energy from violet-blue light and refl ect
green light, giving plants their green color.
Accessory pigments help plants absorb additional light.
For instance, carotenoid

carotenoids : Pigments in plants that absorb light energy for photosynthesis and protect against photo-damage.

Image_carotenoids_0.png

s (kuh ROH tuh noyds) absorb blue
and green light and refl ect yellow, orange, and red light.
Carotenoids give carrots and sweet potatoes their orange color.
Accessory pigments are the reason leaves change colors in
autumn. In green leaves, there is so much chlorophyll that it
masks the other pigments. In autumn, as trees prepare to lose
their leaves, the chlorophyll molecules break down, revealing
the colors of other pigments. The colors red, yellow, and
orange can be seen.
Reading Essentials Chapter 8 Cellular Energy
87
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88
Chapter 8 Cellular Energy Reading Essentials
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
How does electron transpor

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

t

electron transport in photosynthesis : Electrons are excited by light in Photosystem II, moving through the electron transport chain to Photosystem I, and finally contribute to forming NADPH by being transferred to NADP+.

Image_electron-transport-in-photosynthesis_0.png

electron transport : Electron transport in photosynthesis involves the transfer of high-energy electrons through a series of proteins in the thylakoid membrane, which helps generate ATP and NADPH.

Image_electron-transport_0.png

 work?
Photosystem I and phot

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

osystem II ar

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

e made of

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

 pigment

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

s
that absorb lig

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

ht and pr

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

oteins that ar

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

e important in lig

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

ht

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png
reactions

function of pigments : Pigments like chlorophyll absorb specific wavelengths of light to help convert light energy to chemical energy. Chlorophyll is the primary pigment and accessory pigments absorb additional wavelengths for photosynthesis.

Image_function-of-pigments_0.png

photosystem i : A protein complex in the thylakoid membrane involved in capturing light energy for photosynthesis.

Image_photosystem-i_0.png

photosystem ii : Initial protein complex in the thylakoid membrane that contributes to photosynthesis by splitting water molecules.

Image_photosystem-ii_0.png

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

. They are in t

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

he t

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

hylak

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

oid

thylakoid : A flattened sac-like membrane inside the chloroplasts, where light-dependent reactions take place.

Image_thylakoid_0.png

 membrane. Follow
along in the fi gure below as you read about their role in
photosynthesis

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

.
Photosynthesis

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

 begins when light energy causes electrons in
photosystem II to go into a high energy state. The light energy
also causes a water molecule to split, releasing an electron
into the electron transport system, a hydrogen ion into the
thylakoid space, and oxygen as a waste product. The excited
electrons move from photosystem II and move along a series
of electron-carriers to photosystem I. Photosystem I absorbs
more light, and the excited electrons move along electron-
carriers again. Finally, the electrons are moved to NADP⫹,

nadph : An electron carrier that provides the high-energy electrons required to store energy in the light-independent reactions of photosynthesis.

Image_nadph_0.png

forming the energy-storage molecule NADPH.
How is A

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

TP

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

 made during photosynthesis?
ATP is made when light energy causes the water molecule
to split into oxygen and two hydrogen ions (H⫹), or protons.
Protons build up inside the thylakoid. Protons diffuse through
ion channels into the str

stroma : The fluid-filled space inside the chloroplast surrounding thylakoid stacks where light-independent reactions occur.

Image_stroma_0.png

oma

stroma : The fluid-filled space inside the chloroplast surrounding thylakoid stacks where light-independent reactions occur.

Image_stroma_0.png

 where the concentration is lower.
These channels are enzymes called ATP synthases. As protons
move into the stroma, ATP is formed.
5. Describe Of what
are photosystem I and
photosystem II made?
Picture This
6. Identify On the fi gure,
highlight the path that
electrons follow. What
molecule is the electron’s
fi nal destination?
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Phase Two: The Calvin Cycle

calvin cycle : The Calvin cycle, also known as light-independent reactions, is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms. It builds sugars out of carbon dioxide and water using the energy stored in ATP and NADPH, which are produced during the light-dependent reactions.

Image_calvin-cycle_0.png

NADPH and ATP ar

atp : An organic compound that provides energy to cells for biochemical reactions.

Image_atp_0.png

nadph : An electron carrier that provides the high-energy electrons required to store energy in the light-independent reactions of photosynthesis.

Image_nadph_0.png

e temporary storage molecules. During
phase two, also known as the Calvin cycle, the energy in these
molecules is stored in organic molecules, such as glucose.
What happens in the Calvin cycle?
The Calvin cycle builds sugars out of

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png

 carbon di

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png

oxide and

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png
water

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png

 using the energy stored in ATP and NADPH. The Calvin
cycle’s reactions do not r

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

equire sunlight,

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

 which is why they ar

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

e
also referred t

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

o as light

light reactions : Light-dependent reactions are the first phase of photosynthesis where light energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH.

Image_light-reactions_0.png

-independent reactions.
In the Calvin cycle, carbon dioxide molecules combine
with six 5-carbon compounds to make twelve 3-carbon
molecules. The chemical energy stored in ATP and NADPH
is passed to the 3-carbon molecules. Two 3-carbon molecules
leave the cycle to be used to make glucose and other organic
compounds. The enzyme rubisco changes ten 3-carbon

rubisco : Rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase, is an enzyme involved in the first major step of carbon fixation in the Calvin cycle. It catalyzes a reaction between CO2 and ribulose bisphosphate (RuBP), leading to the creation of sugars.

Image_rubisco_0.png

rubisco changes carbon dioxide molecules into organic molecules : Rubisco is an essential enzyme in the Calvin cycle that catalyzes the first step of converting carbon dioxide into organic molecules, which are used by the plant for energy and growth.

Image_rubisco-changes-carbon-dioxide-molecules-into-organic-molecules_0.png

molecules into six 5-carbon molecules to c

rubisco : Rubisco, ribulose-1,5-bisphosphate carboxylase/oxygenase, is an enzyme involved in the first major step of carbon fixation in the Calvin cycle. It catalyzes a reaction between CO2 and ribulose bisphosphate (RuBP), leading to the creation of sugars.

Image_rubisco_0.png

rubisco changes carbon dioxide molecules into organic molecules : Rubisco is an essential enzyme in the Calvin cycle that catalyzes the first step of converting carbon dioxide into organic molecules, which are used by the plant for energy and growth.

Image_rubisco-changes-carbon-dioxide-molecules-into-organic-molecules_0.png

ontinue the cycle.
Because rubisco changes carbon dioxide molecules into
organic molecules that can be used by the cell, it is considered
one of the most important enzymes. Sugar formed in the
Calvin cycle can be used as energy and as building blocks
for complex carbohydrates, such as starch.
Alternative Pathways
Photosynthesis

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

 might be diffi cult for plants that grow in
hot, dry environments. Many plants in extreme climates have
evolved other photosynthesis pathways.
Tropic

corn : A cereal plant widely grown for its edible grain, also using the C4 pathway.

Image_corn_0.png

al plants suc

corn : A cereal plant widely grown for its edible grain, also using the C4 pathway.

Image_corn_0.png

h as sugar cane and c

c4 pathway : The C4 pathway is an alternative photosynthetic process used by certain plants in hot and dry environments. It fixes carbon dioxide into four-carbon compounds instead of three-carbon compounds, allowing these plants to efficiently uptake CO2 while minimizing water loss.

Image_c4-pathway_0.png

sugar cane : A tropical plant that uses the C4 photosynthetic pathway and is known for its use in sugar production.

Image_sugar-cane_0.png

orn use the C

c4 pathway : The C4 pathway is an alternative photosynthetic process used by certain plants in hot and dry environments. It fixes carbon dioxide into four-carbon compounds instead of three-carbon compounds, allowing these plants to efficiently uptake CO2 while minimizing water loss.

Image_c4-pathway_0.png

sugar cane : A tropical plant that uses the C4 photosynthetic pathway and is known for its use in sugar production.

Image_sugar-cane_0.png

4

c4 pathway : The C4 pathway is an alternative photosynthetic process used by certain plants in hot and dry environments. It fixes carbon dioxide into four-carbon compounds instead of three-carbon compounds, allowing these plants to efficiently uptake CO2 while minimizing water loss.

Image_c4-pathway_0.png

sugar cane : A tropical plant that uses the C4 photosynthetic pathway and is known for its use in sugar production.

Image_sugar-cane_0.png

path

c4 pathway : The C4 pathway is an alternative photosynthetic process used by certain plants in hot and dry environments. It fixes carbon dioxide into four-carbon compounds instead of three-carbon compounds, allowing these plants to efficiently uptake CO2 while minimizing water loss.

Image_c4-pathway_0.png

sugar cane : A tropical plant that uses the C4 photosynthetic pathway and is known for its use in sugar production.

Image_sugar-cane_0.png

way

c4 pathway : The C4 pathway is an alternative photosynthetic process used by certain plants in hot and dry environments. It fixes carbon dioxide into four-carbon compounds instead of three-carbon compounds, allowing these plants to efficiently uptake CO2 while minimizing water loss.

Image_c4-pathway_0.png

sugar cane : A tropical plant that uses the C4 photosynthetic pathway and is known for its use in sugar production.

Image_sugar-cane_0.png

. Instead of the 3-carbon molecules o

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

f the Calvi

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

n
cycle,

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

 C4 plants f

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

i x carbon dioxide int

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

o 4

c4 pathway fixes carbon dioxide into 4 carbon molecules : In the C4 pathway, carbon dioxide is initially fixed into a 4-carbon compound, allowing certain plants, like those in tropical areas, to efficiently perform photosynthesis under conditions of intense sunlight while minimizing water loss.

Image_c4-pathway-fixes-carbon-dioxide-into-4-carbon-molecules_0.png

-carbon molecules.
Less water is lost in the C4 pathway. These plants keep their
stomata closed during hot days to minimize water loss.
What are CAM plants?
Another alternative pathwa

cam pathway : The CAM (Crassulacean Acid Metabolism) pathway is an alternative photosynthetic process adopted by plants in arid conditions, where stomata open at night to minimize water loss while fixing CO2 into organic acids for use during the day.

Image_cam-pathway_0.png

y is called the CAM

cam pathway : The CAM (Crassulacean Acid Metabolism) pathway is an alternative photosynthetic process adopted by plants in arid conditions, where stomata open at night to minimize water loss while fixing CO2 into organic acids for use during the day.

Image_cam-pathway_0.png

 pathway.
CAM plants live in deserts, salt marshes

deserts : Arid regions with sparse vegetation and little rainfall where plants like cacti employ CAM photosynthesis.

Image_deserts_0.png

salt marshes : Coastal ecosystems in the intertidal zone, often subject to saltwater exposure, where CAM plants may thrive.

Image_salt-marshes_0.png

, and other environments
where access to water is limited. Cacti and orchid

cacti : Desert plants adapted to dry environments often using CAM photosynthesis to conserve water.

Image_cacti_0.png

orchids : A diverse and widespread family of flowering plants using various photosynthetic adaptations like CAM in some species.

Image_orchids_0.png

s are CAM
plants. Carbon dioxide enters the leaves of CAM plants only
at night, when the atmosphere is cooler and more humid.
The plants also fi x carbon dioxide into organic compounds at
night. During the day, carbon dioxide is released from organic
compounds in the plants. The carbon dioxide en

calvin cycle : The Calvin cycle, also known as light-independent reactions, is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms. It builds sugars out of carbon dioxide and water using the energy stored in ATP and NADPH, which are produced during the light-dependent reactions.

Image_calvin-cycle_0.png

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png

ters the Calvin

calvin cycle : The Calvin cycle, also known as light-independent reactions, is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms. It builds sugars out of carbon dioxide and water using the energy stored in ATP and NADPH, which are produced during the light-dependent reactions.

Image_calvin-cycle_0.png

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png
cycle

calvin cycle : The Calvin cycle, also known as light-independent reactions, is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms. It builds sugars out of carbon dioxide and water using the energy stored in ATP and NADPH, which are produced during the light-dependent reactions.

Image_calvin-cycle_0.png

calvin cycle builds sugars out of carbon dioxide and water : The Calvin cycle, also known as the light-independent reactions, uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide and water into glucose, a sugar that serves as an energy source for the plant.

Image_calvin-cycle-builds-sugars-out-of-carbon-dioxide-and-water_0.png

 at that point. The CAM pat

cam pathway minimizes water loss : The CAM pathway allows plants in dry environments to fix carbon dioxide at night, reducing water loss during the hotter parts of the day and using this fixed carbon for photosynthesis during the day.

Image_cam-pathway-minimizes-water-loss_0.png

hway minimizes water loss,

cam pathway minimizes water loss : The CAM pathway allows plants in dry environments to fix carbon dioxide at night, reducing water loss during the hotter parts of the day and using this fixed carbon for photosynthesis during the day.

Image_cam-pathway-minimizes-water-loss_0.png

while allowing for adequate carbon uptake.
7. Name the main energy-
storing products of each

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png
phase of photosynthesis

photosynthesis equation : The chemical formula for photosynthesis is 6CO2 + 6H2O ⟶ C6H12O6 + 6O2. It summarizes the process in which plants use carbon dioxide and water, powered by sunlight energy, to produce glucose and oxygen.

Image_photosynthesis-equation_0.png

phases of photosynthesis : Photosynthesis occurs in two phases: light-dependent reactions where light energy is converted to chemical energy in the forms of ATP and NADPH, and light-independent reactions where these energy carriers help synthesize glucose.

Image_phases-of-photosynthesis_0.png

photosynthesis : The process by which green plants and some other organisms use sunlight to synthesize foods with the aid of chlorophyll.

Image_photosynthesis_0.png

.
8. Name two places where
CAM plants live.
Reading Essentials Chapter 8 Cellular Energy
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