Photosynthesis Overview and Mechanisms

The primary purpose of photosynthesis in plants is to convert light energy into chemical energy and reducing power.

NADP+ reductase is responsible for forming NADPH during photosynthesis.

Chloroplasts generate a proton gradient through electron transport and chemiosmosis.

<p>Förster resonant energy transfer is a mechanism that facilitates the transfer of energy between chromophores, crucial for efficient light harvesting in photosystems.</p> Signup and view all the answers

<p>Herbicides typically target and disrupt the functions of photosystems, inhibiting the photosynthetic process.</p> Signup and view all the answers

<p>The thylakoid membranes within chloroplasts are essential for the light-dependent reactions of photosynthesis.</p> Signup and view all the answers

<p>The two main types of photosystems involved in photosynthesis are Photosystem I and Photosystem II.</p> Signup and view all the answers

<p>Excessive light can lead to the production of reactive oxygen species (ROS) from water, resulting in the formation of H2O2 and O2.</p> Signup and view all the answers

<p>Atrazine primarily disrupts Photosystem II, leading to the generation of reactive oxygen species (ROS).</p> Signup and view all the answers

<p>Cyclic electron flow allows for the production of ATP without the need for NADPH, supporting the energy demands of the Calvin cycle.</p> Signup and view all the answers

<p>The photolysis of water in Photosystem II produces oxygen, protons (4 H+), and electrons (4 e-).</p> Signup and view all the answers

<p>Low temperatures can slow down the rate of photosynthesis due to the reduced activity of enzymes involved in the light-dependent reactions.</p> Signup and view all the answers

<p>It provides the light energy needed for the conversion to chemical energy.</p> Signup and view all the answers

<p>NADP+ reductase facilitates the reduction of NADP+ to NADPH, which is crucial for the Calvin cycle.</p> Signup and view all the answers

<p>The light harvesting complex optimizes light absorption, enhancing energy transfer to the reaction center.</p> Signup and view all the answers

<p>The displacement of an electron occurs, initiating the electron transport chain.</p> Signup and view all the answers

<p>Chlorophyll a has a maximum absorption near 680 nm, while chlorophyll b absorbs maximally around 650 nm.</p> Signup and view all the answers

<p>Water is oxidized to replenish electrons lost from the reaction center and produces oxygen as a byproduct.</p> Signup and view all the answers

<p>An action spectrum shows the effectiveness of different wavelengths in driving photosynthesis.</p> Signup and view all the answers

<p>The Calvin cycle converts carbon dioxide into glucose using ATP and NADPH produced in the light reactions.</p> Signup and view all the answers

<p>The electron transport chain creates an electrochemical gradient that drives ATP synthesis via chemiosmosis.</p> Signup and view all the answers

<p>Förster resonant energy transfer describes the energy transfer between closely spaced molecules, important in chlorophyll arrangements.</p> Signup and view all the answers

<p>Cyanobacteria were among the first organisms to perform photosynthesis, significantly increasing oxygen levels in the atmosphere.</p> Signup and view all the answers

<p>The stroma is the fluid-filled space surrounding the thylakoids, while thylakoids are membrane-bound structures where photosynthesis reactions occur.</p> Signup and view all the answers

<p>Leaves appear green because chlorophyll absorbs blue and red light while reflecting green light.</p> Signup and view all the answers

<p>The light-dependent reactions produce ATP and NADPH, along with oxygen as a byproduct.</p> Signup and view all the answers

<p>Water provides electrons and protons for the light reactions and produces oxygen when split during photosynthesis.</p> Signup and view all the answers

<p>Thylakoids are organized in stacks to maximize surface area for light absorption and contain the proteins needed for the electron transport chain.</p> Signup and view all the answers

<p>NADP+ acts as an electron carrier, accepting electrons to form NADPH in the light-dependent reactions.</p> Signup and view all the answers

<p>Cyanobacteria were the first organisms to perform photosynthesis, leading to the production of organic compounds.</p> Signup and view all the answers

<p>The overall equation for photosynthesis can be summarized as: $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$.</p> Signup and view all the answers

<p>Photosystem II (PSII) captures light energy to split water molecules, generating oxygen and electrons.</p> Signup and view all the answers

<p>High light intensity can lead to rate-limiting reactions in PSII and cause non-photochemical quenching.</p> Signup and view all the answers

<p>The reaction produces oxygen gas (O2) and protons (H+).</p> Signup and view all the answers

<p>The electron transport chain transfers electrons from PSII to PSI, helping to generate ATP and NADPH.</p> Signup and view all the answers

<p>Zeaxanthin and violaxanthin are involved in photoprotection, helping to prevent damage from excess light.</p> Signup and view all the answers

<p>Low pH activates Violaxanthin De-Epoxidase (VDE), promoting the conversion of violaxanthin to zeaxanthin.</p> Signup and view all the answers

<p>Too many protons in the thylakoid lumen can disrupt the proton gradient necessary for ATP synthesis.</p> Signup and view all the answers

<p>NADP+ accepts electrons leading to the formation of NADPH, which occurs mainly at the end of the light reactions.</p> Signup and view all the answers

<p>Cyt b6f complex facilitates the transfer of electrons from plastoquinol (PQ) to plastocyanin (PC).</p> Signup and view all the answers

<p>The stroma is the fluid-filled space where the light-independent reactions take place, utilizing NADPH and ATP.</p> Signup and view all the answers