Photosynthesis Flashcards
Where are disc-like structures called thylakoids arranged within each chloroplast, and what are they known as?
Thylakoids are arranged in piles called grana.
What is the pigment found in the membrane of each thylakoid that absorbs light?
Chlorophyll
What is the fluid-filled space around the grana called?
The stroma
Where do the Light reactions take place, and what is required for them to occur?
Light reactions occur in the Thylakoid membrane and require constant solar energy.
Where do the Dark reactions occur, and do they require direct solar energy?
Dark reactions occur in the stroma and do not require direct solar energy.
What happens when a pigment absorbs a photon during photosynthesis?
When a pigment absorbs a photon, it is raised to an excited state, meaning that one of its electrons is boosted to a higher-energy orbital.
What is the function of the pigment molecules in a photosystem during photosynthesis?
Collectively, the pigment molecules collect energy and transfer it towards a central part of the photosystem called the reaction center.
What does the reaction center of a photosystem contain, and what are its properties?
The reaction center of a photosystem contains a unique pair of chlorophyll molecules called the special pair.
What happens once energy reaches the special pair in a photosystem during photosynthesis?
Once energy reaches the special pair, it passes an entire electron to the primary electron acceptor.
What happens to light collected by the special pair P680 during photosynthesis?
Light collected by special pair P680 donates an electron to the primary electron acceptor.
Describe the pathway of an electron leaving Photosystem II (PSII) in the Electron Transport Chain.
When an electron leaves PSII, it is transferred first to plastoquinone (Pq), then to a cytochrome complex (Cyt), and finally to plastocyanin (Pc).
How is energy utilized as an electron travels in the Electron Transport Chain during photosynthesis?
As the electron travels, some of the energy is used to pump protons across the stroma to the thylakoid lumen.
What is formed as a result of the transfer of protons and the release of H+ from the splitting of water during photosynthesis?
The transfer of protons and the release of H+ form a proton gradient.
Describe the role of protons moving down their concentration gradient during photosynthesis.
Protons move down their concentration gradient through ATP synthase, creating ATP.
What occurs in the Light-Independent Reactions (LIR) of photosynthesis?
. In the LIR, carbon atoms from CO2 are fixed and used to build glucose.
What are the essential components provided by the light reactions for the Light-Independent Reactions (LIR)?
ATP and NADPH from the light reactions are essential for the LIR.
Where do the Light-Independent Reactions (LIR) take place within the chloroplast?
The reactions take place in the stroma of the chloroplast.
Describe the first step of carbon fixation in the Light-Independent Reactions (LIR) of photosynthesis.
A CO2 molecule combines with a five-carbon acceptor molecule, ribulose-1,5-bisphosphate (RuBP).
What is the result of the combination of a CO2 molecule with ribulose-1,5-bisphosphate (RuBP) during carbon fixation in the LIR?
A six-carbon compound is created that splits into two molecules of a three-carbon compound, 3-phosphoglyceric acid (3-PGA).
Which enzyme catalyzes the reaction that splits the six-carbon compound into two molecules of 3-phosphoglyceric acid (3-PGA) during carbon fixation in the LIR?
This reaction is catalyzed by the enzyme rubisco.
What role do ATP and NADPH play in the Reduction stage of the Light-Independent Reactions (LIR) of photosynthesis?
ATP and NADPH are used to convert the 3-PGA molecules into a three-carbon sugar, glyceraldehyde-3-phosphate (G3P).
Why is the Reduction stage of the Light-Independent Reactions (LIR) named as such?
. This stage gets its name because NADPH donates electrons to, or reduces, a three-carbon intermediate to make G3P.
What happens to some of the G3P molecules produced during the Light-Independent Reactions (LIR) of photosynthesis?
Some G3P molecules go to make glucose
What is the fate of the G3P molecules that are not used to make glucose during the LIR?
Others must be recycled to regenerate the RuBP acceptor.
What resources are required for the process of regenerating the RuBP acceptor during the Light-Independent Reactions (LIR) of photosynthesis?
Regeneration requires ATP and involves a complex network of reactions.
