Here we will talk about Which process is most directly driven by light energy? It’s a biology question we post here to learn more about photosynthesis to prepare for the MCAT test.
Which process is most directly driven by light energy?
When it comes to photosynthesis, Which process is most directly driven by light energy?
- reduction of NADP+ molecules
- carbon fixation in the stroma
- removal of electrons from chlorophyll molecules
- creation of a pH gradient by pumping protons across the thylakoid membrane
- Below are the answer and explanations of this question.
Photosynthesis
Photosynthesis is a process in which green plants absorb light energy and synthesize carbon dioxide and water into energy-rich organic matter, while releasing oxygen, and consists of two main stages: light and dark reactions.
The process of photosynthesis is a relatively complex issue. On the surface, the total reaction formula of photosynthesis seems to be a simple redox process.
But in essence, it includes a series of photochemical steps and material transformations.
According to modern information, the whole photosynthesis can be roughly divided into 3 major steps as follows.
1. the primary reaction, including the absorption, transfer, and conversion of light energy.
2. electron transfer and photosynthetic phosphorylation, forming active chemical energy (ATP and NADPH).
3. carbon assimilation, which converts the active chemical energy into stable chemical energy (fixation of CO2, formation of sugars)
Photosynthetic center
The photosynthetic center, also known as the reaction center, is the most basic pigment-protein structure for primary reactions.
It consists of at least one photoconverting pigment molecule (P), a primary electron acceptor (A), and a primary electron donor (D) in order to cause charge separation, conversion of light energy to electrical energy, and accumulation.
The photosynthetic center can be considered as the basic unit of light energy conversion.
Photochemical reaction is the central link of photosynthesis, which converts light energy directly into chemical energy.
When a specific chlorophyll a pair (P) is excited by light it becomes the excited state P*, which releases electrons to the primary electron acceptor (A). Chlorophyll a is oxidized to the oxidized state with a positive charge (P+), while the acceptor is reduced to the reduced state with a negative charge (A-). Oxygenated
The chlorophyll in the oxidized state (P+) can be restored to the reduced state by gaining electrons from the secondary electron donor (D) after losing electrons.
In this way, the primary electron acceptor continuously redoxes, releasing high-energy electrons into the electron transport chain up to the final electron acceptor.
Similarly, the electron donor of the oxidation state (D+) also wants to take electrons from the previous donor, once until the final electron donor water.
The photochemical reactions in the photoreaction center are as follows.
Correct Answer
Here is the correct answer to Which process is most directly driven by light energy.
- C. removal of electrons from chlorophyll molecules
The process of removal of electrons from chlorophyll molecules is most directly driven by light energy.
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