converts solar energy into chemical energy
uses the energy of sunlight to make organic molecules from H2O and CO2
where CO2 enters and O2 exits the leaf
the interior tissue of the leaf, chloroplasts are found here
How many chloroplasts are in a mesophyll cell
dense fluid in chloroplast
Photosynthesis Redox Process
H2O is oxized, CO2 is reduced
What two reactions are part of Photosynthesis
Light reactions and the Calvin Cycle
split H2O, release O2, reduce NADP to NADPH, generate ATP from ADP by photophosphorylation
The Calvin Cycle (stroma) forms sugars from
CO2 usng ATP and NADPH
The carbon cycle begins with
changes CO2 into organic molecules
What are solar powered chemical factories
Chloroplasts transform light into chemical energy by using
ATP and NADPH
Light travels in
What determines the type of electromagnetic energy?
What is the entire range of electromagnetic energy
Wavelengths that produce the color we see
substances that absorb visible light
Different pigments absorb different
Why do leaves appear green?
Chlorophyll reflects and transmits green
A spectrophotometer can be used to measure
the absorption spectrum of a substance
Graph plotting a pigments light absorption versus wavelengths
Relative effectiveness of different wavelengths of radiation in driving a process
When a pigment absorbs light
it goes from ground state to excited state
When excited electrons fall back to the ground state
photons are given off (fluorescence)
Reaction center complex surrounded by light-harvesting complexes
Light Harvesting Complex
pigment molecules bound to proteins
What funnels the energy of photons to the reaction center?
Light Harvesting Complex
Primary Electron Acceptor
Accepts an excited electron from Chlorophyll A
What is the first step in Light Reactions?
Electron transfer from Chlorophyll A to primary electron acceptor
Which Photosystem absorbs a wavelength at 689 nm
PS II reaction center chloropyhll A is called
Which Photosystem absorbs a wavelength at 700 nm
Two routes for electron flow during light reactions
Cyclic and Linear
Linear Electron Flow
Primary Pathway: involves both photosystems and produces ATP and NADPH using light energy
Cyclic Electron Flow
uses only Photosystem I and produces ATP (but NOT NADPH)
Generate ATP in Mitochondria and Chloroplast
Chemiosmosis in the Mitochondria, chemical energy is transferred from what to what?
Food to ATP
Chemiosmosis in the Chloroplast, chemical energy is transferred from what to what?
Light to ATP
What does the Calvin Cycle use to convert CO2 to Sugar
ATP and NADPH
What are the three phases in the Calvin Cycle?
1. Carbon Fixation 2. Reduction 3. Regeneration of the CO2 acceptor
On hot and dry days, what part of the Plant closes to conserve Water?
The photosynthetic mMembranes are found in the _____ in plant cells.
In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
ultraviolet radiation and infrared radiation
What is the product of light reactions during photosynthesis?
NADPH, high energy electrons, oxygen, ATP
When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.
Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is_ _____ during the Calvin Cycle.
What product is consumed during the Calvin Cycle of photosynthesis??
What is the overall function of the Calvin Cycle
C4 plants occur more commonly in desert conditions because _____
they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed
The Carbon fixation involves the addition of carbon dioxide to _____.
After 3-PGA is phosphorylated, it is reduced by _____.
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
Energized electrons from photosystem I are used to reduce what?
What part of the plant contains chlorophyll?
Stacked thylakoids are called?
Where does light reactions occur?
Where does the Calvin Cycle occur?
The light reactions of photosynthesis use _____ and produce _____.
What type of plants are found in tropical grasses?
Where s CAM found
In C3 plants the conservation of water promotes _____.
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
Accessory pigments within chloroplasts are responsible for
absoring photons of different wavelengths of light and passing that energy to P680 or P700
Linear Electron flow along with chemiosmosis in the chloroplast results in the production of
ATP, NADPH, and O2
CAM plants avod photorespiration by
fixing CO2 into organic acids during the night; these acids then release CO2 during the day
What are the final electron acceptors for the ETC in the light reactions of photosynthesis and in cellular respiration?
NADP+ in light reactions, O2 in respiration
Chloroplasts can make carbs in the dark if provided with
ATP, NADPH, and CO2
What does the rubisco do
adds CO2 to RuBP in the carbon fixation stage
In photosynthesis, plants use carbon from _____ to make sugar and other organic molecules.
How does carbon dioxide enter the leaf?
Through the Stomata
In a rosebush, chlorophyll is located in _____.
thylakoids, which are in chloroplasts in the mesophyll cells of a leaf
Chlorophyll molecules are in which part of the chloroplast?
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from _____.
In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up ______.
in sugar molecules and in water
Molecular oxygen is produced during _____.
the light reactions of photosynthesis
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle depends on products of the light reactions.
The photosynthetic event known as the Calvin cycle occurs in the _____.
the wavelengths of light most effective in driving photosynthesis are referred to as _____.
The action Spectrum
Where do the electrons needed by photosystem II originate?
During photosynthesis in chloroplasts, O2 is produced from ______ via a series of reactions associated with ______.
H2O; photosystem II
Which one of the following is cycled in the cyclic part of light reactions?
Both mitochondria and chloroplasts _____.
use a hydrogen ion (proton) gradient to produce ATP
During photosynthesis in a eukaryotic cell, a high proton concentration accumulates or is formed in the ______.
(inner) thylakoid space
The light reactions of photosynthesis generate high-energy electrons, which end up in ____. The light reactions also produce ____ and ____.
NADPH ... ATP ... oxygen
The energy used to produce ATP in the light reactions of photosynthesis comes from _____.
movement of H+ through a membrane
What is the role of NADP+ in photosynthesis?
It is reduced and then carries electrons to the Calvin cycle.
In the Calvin cycle, CO2 is combined _____.
with a 5-carbon compound to form an unstable 6-carbon compound, which decomposes into two 3-carbon compounds