36 terms


What equation best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
Where does the Calvin cycle occur?
in the stroma of a chloroplast
The light reactions of photosynthesis use _____ and produce _____.
water.... NADPH
_____ has a longer wavelength than _____.
What enzyme phosphorylates ADP to make ATP?
ATP synthase
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
electron transport chain
_____ splits water into 1/2 O2, H+, and e- .
photosystem II
Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.
photosystem I
Chlorophyll can be found in _____.
photosystems I & II
The light reactions of photosynthesis supply the Calvin cycle with
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O ---> NADPH ---> Calvin cycle
True or false- Oxygen is produced during the Calvin cycle?
Plants are photoautotrophs. What does this mean?
They are among the producers of the biosphere. They make their own food from inorganic materials. They are in the same category as algae and cyanobacteria. They use light energy to drive the synthesis of organic molecules
The ultimate source of energy to support most life on Earth is _____.
The photosynthetic membranes 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 are the products of the light reactions of photosynthesis?
high-energy electrons, NADPH, ATP, oxygen
When light strikes chlorophyll molecules, they lose electrons, which are ultimately replaced by _____.
splitting water
Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is_ _____ during the Calvin Cycle.
The overall function of the Calvin cycle is _____.
making sugar
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
Define autotrophic
self-feeder, produce their organic molecules from CO2 and other inorganic raw materials obtained from their environment
Define heterotrophic
obtain their organic material by feeding on compunds produced by other organisms
What is the role of redox reactions in photosynthesis?
H2O is split, electrons are transferred along with hydrogen ions from H2o to CO2, reducing it to sugar. Electrons increase in potential energy as they move from H2o to C6H12O6, this process requires energy (endergonic). Energy boosts are provided by light
What takes place during the light reactions in photosynthesis?
takes place in thylakoid membranes, use solar energy to produce ATP and NADPH, supplies chemical energy and reducing power (solar energy to chemical energy)
What takes place during the Calvin Cycle in photosynthesis?
incorporates CO2 into organic molecules prucing sugar (chemical energy to sugar)
What wavelengths are most effective for photosynthesis?
violet-blue/ red light are most effective in driving photosythesis
Explain what happens when a solution of chlorophyll a absorbs photons. Explain what happens when chlorophyll a in an intact chloroplast absorbs photons.
chlorophyll a- (CH3) absorbs at slightly different wavelengths, blue-green color
chlorophyll b- (CHO) olive-green color due to structural differences
List the components of a photosystem and explain the function of each component.
reaction center complex- includes special pair of chlorophyll a molecules
photon- strikes a pigment molecule in light-harvesting complex
energy- passed from molecule to molecule until it reaches reaction center complex
Excited electron (e-)- form "special e-"- transferred to primary e- receptor path
Trace the movement of electrons in noncyclic electron flow.
drives light driven electrons to water to NADPH
Trace the movement of electrons in cyclic electron flow.
an alternative path which uses photosystem I not photosystem II, electrons cycle back to compensate for the lack of ATP and overflow of NADP+
Explain the function of cyclic electron flow.
electron shunt supplements the supply of ATP, does not produce NADPH
Describe the similarities in chemiosmosis between oxidative phosphorylation in mitochondria and photophosphorylation in chloroplasts.
Electron transport chain in membrane pumps protons across membrane, electrons are passed through a series of carriers (progressively more electronegative) ETC transform redox energy to a proton-motive force, potential energy stored as H+ gradient across a membrane. ATP synthase complex- diffuse H+ ions down their gradient to the phosphorylation of ADP.
Descibe the differences in chemiosmosis between oxidative phosphorylation in mitochondria and photophosphorylation in chloroplasts.
In mitochondria electrons move down the ETC extracted from organic molecules and oxidized chloroplasts electrons come from H2O
Describe the role of ATP and NADPH in the calvin cycle.
The calvin cycle uses energy from ATP/ NADPH to convert CO2 to CH2O, CO2 enters the calvin cycle ---> spends ATP/ consumes NADPH as reducing power- adds high energy electrons to produce sugar
Listen the possible fates of photosynthetic products.
Sugar made in the chloroplasts supplies the entire plant with chemical energy and carbon skeletons for the synthesis of all the major organic molecules of plant cells