Chapter 6
Once a plant has initially captured the energy of a photon
-a series of reactions occurs in chloroplast membranes of the cell. -the energy is transferred through several steps into a molecule of ATP. - several pigments, including two kinds of chlorophyll, may be involved
Accessory pigments
-other pigments besides chlorophyll -absorb light levels that chlorophyll does not -give color to flowers, fruits, and vegetables -present in leaves-but masked by chlorophyll until the fall when the chlorophyll is broken down
Making sugars
-the carbons are shuffled about through a series of reactions to make sugars
The ______ consist of capturing energy from sunlight and using it to make ATP and NADPH.
light-dependent reactions
Calvin Cycle
-Assembles sugar molecules from CO2 -Energy for building sugars comes from products of the light reactions (ATP and NADPH)
Carbon fixation
-carbon from CO2 in the air is attached to an organic molecule, RUBP
Where are light-absorbing pigments found within chloroplasts?
embedded in the thylakoid membranes
chlorophyll molecules and proteins are embedded in the
thylakoid membranes inside chloroplasts
Photosynthesis takes places in three stages
1.capture energy from sunlight 2. Use captured energy to make ATP & NADPH 3. Use ATP & NADPH to make carbohydrates
Write the overall equation for photosynthesis.
6CO2 + 6H2O --> light energy C6H12O6 + 6O2
The calvin cycle recycles reactants needed for the light dependent reactions, it return _____ needed for chemiosmosis in photo system II and return ______ that goes back to the ETS of photosystem I
ADP then turns to ATP; NADP+ that converts to NADPH.
What is required for endergonic reactions to work?
ATP
protons can only re-enter the stroma by traveling through a protein channel called
ATP synthase
high energy electrons generated by photosystem II are used to make _____ Electrons then passed to photosystem I to produce _______
ATP; NADPH
what is needed for redox reactions to occur?
NADPH is needed, it donated hyrodgens and electrons
Plants produce both ATP and NADPH by _____ then electrons end up in NADPH ______
Non-cyclic photophosphorylation
What is added from CO2 from each "turn" of the calvin cycle?
One carbon
What are products of the light-dependent reactions.
Oxygen NADPH ATP
In plants and algae, a complex of chlorophyll molecules and accessory pigments embedded within a matrix of protein molecules is called a _____, which occurs in the membranes of thylakoids
Photosystem
Together chlorophyll molecules arrange to form a _______ which acts as an antenna to capture photons.
Photosystem
The colors of light that are most effective for photosynthesis are
Red,Blue,orange
§ Calvin Cycle (light-independent reactions)
Result: organic molecules (glucose) made Does not need light to occur
light reactions
The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.
The calvin cycle
The products of the light-dependent reactions are used to build organic molecules
What is the internal membrane of the chloroplast called?
Thylakoids
What is a photosystem?
a cluster of chlorophyll molecules arranged in a network
What is a photon?
a packet of light energy
Visible light occupies what part of the electromagnetic spectrum?
a small portion in the middle of the spectrum
•as protons cross the ATP synthase, ADP is phosphorylated into ATP, the process is called
chemiosmosis
ATP provided by ______ powers the reactions of the Calvin cycle, and NADPH provided by ______ is a source of electrons and hydrogens for the Calvin cycle.
chemiosmosis; the electron transport chain of photosystem I
•All stages of photosynthesis take place in the
chloroplasts
photosystem
cluster of chlorophyll and proteins found in thylakoids. The pigment is called chlorophyll and it captures energy from the sun.
Visible Light
electromagnetic waves that you can see
NADPH is recycled during photosynthesis. It is produced during the ________ and used in the_________.
electron transport system of photosystem I, Calvin cycle
the thylakoid membrane is
impermeable to protons
The enzymes and other proteins that are found in the stroma of the chloroplast function ______.
in the assembly of organic molecules
storma
is a semiliquid substance that surrounds the thylakloids
Pigments
light absorbing molecules Main pigment in plants is chlorophyll, it absorbs blue and red lights.
1.Photosynthesis consists of 2 linked sets of reactions. The __ reactions convert light E to chemical E. The __ assembles sugar molecules from carbon dioxide.
light dependent; Calvin cycle
The light-dependent reactions of photosynthesis occur on
membranes
Plants use two photosystems to capture energy used to produce ATP and NADPH. The electrons used in these photosystems
only go through the system once; they are obtained by splitting a water molecule.
What is the loss of electrons called?
oxidation
The Calvin cycle must "turn" ____ times in order to form a new glucose molecule
six
Within the chloroplast, a semi-liquid substance called ______ fills the interior and contains enzymes that act to assemble organic molecules. Also present are numerous internal membranes called ______.
stroma; thylakoids
Most of the energy used by almost all living cells ultimately comes from the
sun
Reforming RUBP
the remaining molecules are used to reform RUBP The orgiinal 5-carbon sugars are needed to start this process.
Plants capture sunlight
with molecules called pigments that absorb photons and use their energy
§Which organisms can do photosynthesis?
•Plants, algae, and some bacteria
As a result of the proton pump of the ETS
•large concentration of protons builds up in the thylakoid space
light-dependent reactions
•take place only in the presence of light •Products: - ATP - NADPH - Oxygen
Description of the light-independent reactions.
CO2 is used in the Calvin Cycle. ATP and NADPH are used in the stroma. Carbohydrates are produced.
What three stages does the calvin cycle occur in?
Carbon fixation Making sugars Reforming RUBP
During photosynthesis, ATP molecules are generated by
Chemiosmosis
What three materials are needed for Calvin Cycle?
Energy, Reducing power (electrons, and carbon dioxide
What happens during the light-independent reactions, also called the Calvin Cycle?
Glucose is produced.
What are thylakoids that are stacked up in columns called?
Grana
How does chlorophyll function in photosynthesis?
It absorbs energy from light.
Photosystem I
absorbs another photon of light, releases an excited electron to another ETS. the ETS produces NADPH, the electron from Photosystem II replaces the electron from the reaction center.
The overall purpose of the Calvin cycle is to
build sugar molecules
What is the role of the antenna complex in noncyclic photophosphorylation?
capture energy from photons and funnel it to the reaction center
Photosystem II
captures a photon of light, releases an excited electron to the transport system (ETS) . The ETS then produces ATP, a molecule of water is split to replace the excited electron from the reaction center.
What occurs during the light-dependent reactions?
capturing energy from sunlight using energy to make ATP and NADPH
Photons
packets of light energy
Some organisms can capture the sunlight energy by a process called
photosynthesis
The energy that is used by almost all living things on our planet comes from the sun. It is captured by plants, algae, and some bacteria through the process of
photosynthesis
During photosynthesis, the structure that consists of an arrangement of chlorophyll molecules that capture solar energy is called a ______.
photosystem
Light-dependent reactions occur within a complex of proteins and pigments called
photosystems
The assembly of organic molecules from carbon dioxide is carried out by ______.
proteins and enzymes found in the stroma
Electrons that leave photosystem II are passed down an electron transport system and provide the energy to ______.
pump protons from the stroma to the thylakoid space
energy is passed along to other pigments until it reaches the
reaction center chlorophyll molecule
What is the gain of electrons called?
reduction