Chapter 10: Photosynthesis Flashcards
What are the 3 phases of photosynthesis?
- Carbon Fixation
- Reduction
- Regeneration of CO2 acceptor (RuBP)
Where does the light reaction occur?
The Thylakoid membrane
What’s the final electron acceptor?
NADP+
What goes into the Calvin Cycle (Dark Reaction)?
3 molecules of CO2, 6 NADPHs, and 9 ATPs
Carbons enters the cycle as CO2 and leaves as:
a 3 carbon sugar: G3P
How many ATP and NADPH do we need to make 1 G3P?
18 ATP and 12 NADPH
Where does the Calvin Cycle occur?
Stroma
Where does the Light Reaction occur?
Thylakoids
ATP and NADPH are used to synthesize organic molecules. What is this cycle called?
Calvin Cycle
Is the Calvin Cycle catabolic or anabolic?
Anabolic: building organic molecules from smaller components requiring energy to do so
What does Rubisco do?
Catches CO2 from the atmosphere and attaches it to a sugar called ribulose biphosphate
What are the 3 phases of photosynthesis?
- Carbon Fixation
- Reduction
- Regeneration of CO2 acceptor (RuBP)
Generation of proton gradients across membranes occurs during
both photosynthesis and respiration
In a plant leaf, the reactions that produce NADH occur in
neither the light reactions nor the Calvin cycle.
Reactions that require CO2 take place in
the Calvin cycle alone.
Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
Other pigments absorb light in addition to chlorophyll a.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
the synthesis of ATP
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules
What best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
neither photosynthesis nor respiration.
What is the relationship between the wavelength of light and the quantity of energy per photon?
They are inversely related
How many carbons are in ribulose
5
Used to generate ATP molecules during photosynthesis
ATP synthase
Pigments that can absorb light energy in photosynthetic organisms
Chlorophyll
The difference in the number of hydrogen ions in the thylakoid lumen as compared to the stroma
1000 fold
The only type of chlorophyll that participate DIRECTLY in the light reaction
Chlorophyll A
An organism that cannot produce its own chemical energy
heterotroph
Electron flow that occurs between photosystem II and I
Non-cyclic
The color of light energy that is least useful in photosynthesis
Green
Sacs within the stroma that contain chlorophyll and are the specific sites of the light reaction stage of photosynthesis
Thylakoids
The number of NADPH required to produce one 3-carbon sugar in the dark reaction
6
The by-product of the first step of the light reaction of photosystem II. Produced by splitting water molecules
Oxygen
Split in the first step of the light reaction of photosystem II to replenish the electron lost from p680
water
The chlorophyll molecule in the center of photosystem II absorbs light energy at 700nM
p700
Organelles found in photosynthesis organisms that are the sites of photosynthesis
Chloroplasts
Dark reaction in photosynthesis that converts CO2 into three-carbon sugars using ATP and NADPH generated in the light reaction
Calvin Cycle
The order (from lowest energy to highest energy) of light in the visible light spectrum
ROYGBIV
Electron flow that occurs only in photosystem I. Used to generate additional ATP needed for the Calvin Cycle.
Cyclic electron flow
The complex of accessory pigments that transfers light energy to a central chlorophyll pigment
Antenna
The number of ATPs required to produce one 3-carbon sugar in the dark reaction
9
What event occurs in the light reactions of photosynthesis?
NADP is produced
In a plant cell, where are the ATP synthase complexes located?
the Thylakoid membrane and inner mitochondrial membrane
Reactions that require CO2 take place in
The Calvin cycle alone
What is the primary function of the Calvin cycle?
synthesize simple sugars from carbon dioxide
Which of the following does not occur during the Calvin cycle?
release of oxygen
The light reactions of photosynthesis supply the Calvin cycle with
ATP and NADPH
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
harvest photons and transfer light energy to the reaction-center chlorophyll
Reduction of oxygen to form water occurs during
respiration only
Which process is most directly driven by light energy?
removal of electrons from chlorophyll molecules
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
the stroma to the thylakoid space.
The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?
The pH within the thylakoid is less than that of the stroma.
