Photosynthesis and Eukaryotic Cells Quiz

Donates high energy electrons to an electron transport chain (ETC).

Cytochrome complex.

Reducing PC.

<p>Accepts low energy electrons from PC and re-excites them.</p> Signup and view all the answers

<p>NADP+ reductase.</p> Signup and view all the answers

<p>Delivers high energy electrons to NADP+ reductase.</p> Signup and view all the answers

<p>The electrons released during photolysis are initially at a low energy level. They are then energized by the Photosystem II (PSII) complex, which uses light energy to excite the electrons to a higher energy state. These high-energy electrons are then passed through the electron transport chain, which includes the cytochrome complex and Photosystem I (PSI). As the electrons move through these components, they lose energy in a stepwise manner, ultimately reaching a lower energy state. The energy released during this process is used to pump protons (H+) across the thylakoid membrane, creating a proton gradient that drives ATP synthesis.</p> Signup and view all the answers

<p>Photolysis refers to the splitting of water molecules by the Photosystem II (PSII) complex during the light reactions. This process releases electrons, hydrogen ions (H+), and oxygen gas as by-products. The release of electrons is crucial as it initiates the electron transport chain, which ultimately drives the synthesis of ATP and NADPH. The oxygen gas released is a by-product of photosynthesis.</p> Signup and view all the answers

<p>The proton gradient created by the movement of electrons through the electron transport chain is used to power the enzyme ATP synthase. As protons flow down their concentration gradient from the thylakoid lumen to the stroma, ATP synthase uses this energy to phosphorylate ADP, producing ATP. This process is known as photophosphorylation and is the primary mechanism for ATP synthesis during the light reactions of photosynthesis.</p> Signup and view all the answers

<p>The Calvin Cycle consists of three major phases: 1) Carbon fixation phase: In this phase, CO2 is covalently bonded to the 5-carbon molecule ribulose-1,5-bisphosphate (RuBP) by the enzyme Rubisco, generating two 3-carbon organic molecules. 2) Reduction phase: The 3-carbon molecules are reduced to form glyceraldehyde-3-phosphate (G3P) using the energy and reducing power from ATP and NADPH, respectively, generated in the light reactions. 3) Regeneration phase: Some G3P molecules are used to regenerate RuBP for the next cycle, while the remaining G3P molecules are exported for the synthesis of other organic compounds.</p> Signup and view all the answers

<p>The main products of the light reactions are ATP and NADPH. ATP is a high-energy molecule that provides the energy required for various cellular processes, including the Calvin cycle in photosynthesis. NADPH is a reducing agent that provides the electrons needed for the reduction of carbon dioxide (CO2) to organic compounds during the Calvin cycle.</p> Signup and view all the answers

<p>The glyceraldehyde-3-phosphate (G3P) produced during the Calvin Cycle can be used as a precursor for the synthesis of various organic molecules. Some examples include: 1) Fatty acids: G3P can be converted into pyruvate, which can then enter the citric acid cycle to produce acetyl-CoA, a precursor for fatty acid synthesis. 2) Amino acids: G3P can be converted into 3-phosphoglycerate, which can then enter the glycolytic pathway and eventually lead to the production of various amino acids. 3) Nucleic acids: G3P can be converted into ribose-5-phosphate, which is a precursor for the synthesis of nucleotides and, subsequently, nucleic acids like DNA and RNA.</p> Signup and view all the answers

<p>To generate a proton gradient across the thylakoid membrane</p> Signup and view all the answers

<p>Photosystem II -&gt; PQ -&gt; Cytochrome complex -&gt; PC -&gt; Photosystem I -&gt; FD -&gt; NADP+ reductase</p> Signup and view all the answers

<p>To reduce NADP+ to NADPH</p> Signup and view all the answers

<p>To pump hydrogen ions across the thylakoid membrane</p> Signup and view all the answers

<p>To accept electrons from the cytochrome complex and transfer them to Photosystem I</p> Signup and view all the answers

<p>To transfer electrons from Photosystem I to NADP+ reductase</p> Signup and view all the answers

<p>To synthesize ATP through the process of chemiosmosis</p> Signup and view all the answers

<p>To reduce NADP+ to NADPH</p> Signup and view all the answers

<p>To provide the enzymes and substrates for the Calvin cycle</p> Signup and view all the answers

<p>Photophosphorylation</p> Signup and view all the answers

<p>CO2</p> Signup and view all the answers

<p>G3P</p> Signup and view all the answers

<p>Resupply PSII</p> Signup and view all the answers

<p>G3P</p> Signup and view all the answers

<p>Make other organic molecules</p> Signup and view all the answers

<p>Oxygen</p> Signup and view all the answers

<p>Rubisco</p> Signup and view all the answers

<p>Photosystem II</p> Signup and view all the answers

<p>Cytochrome complex</p> Signup and view all the answers

<p>Reducing ferredoxin</p> Signup and view all the answers

<p>NADP+</p> Signup and view all the answers

<p>Donating high energy electrons</p> Signup and view all the answers

<p>Reduces ferredoxin back to high energy level</p> Signup and view all the answers

<p>Donating high energy electrons to Photosystem I</p> Signup and view all the answers

<p>To generate a proton gradient that powers ATP synthase</p> Signup and view all the answers

<p>Rubisco</p> Signup and view all the answers

<p>To split water molecules and release electrons, protons, and oxygen</p> Signup and view all the answers

<p>To be exported out of the chloroplast for use in other metabolic processes</p> Signup and view all the answers

<p>PSII -&gt; PQ -&gt; Cyt b6f -&gt; PC -&gt; PSI -&gt; FD -&gt; NADP+ reductase</p> Signup and view all the answers

<p>To reduce NADP+ to NADPH using electrons from the electron transport chain</p> Signup and view all the answers

<p>G3P</p> Signup and view all the answers

<p>To generate a proton gradient that powers ATP synthase</p> Signup and view all the answers

<p>To transfer electrons from Photosystem II to the cytochrome b6f complex</p> Signup and view all the answers

<p>To reduce NADP+ to NADPH using high-energy electrons from the electron transport chain</p> Signup and view all the answers