During this stage, light energy is converted into adenosine triphosphate (ATP) and NADPH. Up to this point, only energy—not electrons—has been transferred between molecules. Describe {eq}3 {/eq} similarities and {eq}3 {/eq} differences between the light reactions of photosynthesis and oxidative phosphorylation in cellular respiration. The process of photosynthesis is made up of light dependent reactions (the photo’ part) and sugar making or light independent reactions (the synthesis part). These energy carriers are used in the light-independent reactions to drive the energetically unfavorable process of “fixing” inorganic CO2 in an organic form, sugar. Light-Independent Reactions . 56007215-Previous-IB-Exam-Essay-Questions, University of Maryland, University College, Jeddah Private College • BUSINESS BUS 121, University of Maryland, University College • BIOL 101, Midwestern State University • HISTORY 101, ib_bio_previous_ib_exam_essay_questions (1).docx, Chief Sealth International High School • IB BIOLOGY HL, University of British Columbia • BIOL MISC. Hydrogen sulfide (H2S) or thiosulfate (S2O2−3)(S2O32−) can serve as the electron donor, generating elemental sulfur and sulfate (SO2−4)(SO42−)ions, respectively, as a result. Photosynthesis takes place in two sequential stages: the light-dependent reactions and the light-independent reactions (Figure \(\PageIndex{1}\)). Although the Calvin Cycle is not directly dependent on light, it is indirectly dependent on light since the necessary energy carriers ( ATP and NADPH) are products of light-dependent reactions. Protons are also transfered during … Explain how the light-independent reactions of photosynthesis rely on light-dependent, 9. Explain. Describe how. Light-dependent reactions need light energy and are the first step of photosynthesis. 10. *Response times vary by subject and question complexity. B. NADPH and ATP This short animation describes the light reactions of photosynthesis. The source of this electron (H2A) differentiates the oxygenic photosynthesis of plants and cyanobacteria from anoxygenic photosynthesis carried out by other types of bacterial phototrophs (Figure \(\PageIndex{4}\)). But let's focus first on the light-dependent reactions. The sunlight is converted to chemical energy during these reactions. In the first part of photosynthesis, the light-dependent reaction, pigment molecules absorb energy from sunlight. Steps of Photosynthesis. PLAY. In the light-dependent reactions, energy from sunlight is absorbed by pigment molecules in photosynthetic membranes and converted into stored chemical energy. The flow of electrons in this way is called the Z-scheme. Thes… In cyanobacteria, for example, these infolded regions are also referred to as thylakoids. The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem. False. Energy from the sun's light raises two electrons from each chlorophyll molecule to a higher energy level. The light-dependent reactions produce the energy-rich ATP and NADPH that ARE THEN USED by the light-independent reactions to synthesize sugars by fixing carbon dioxide. A. to the outside of the plasma membrane Median response time is 34 minutes and may be longer for new subjects. In the light-dependent reaction s , energy from sunlight is absorbed by pigment molecules in photosynthetic membranes and converted into stored chemical energy. An enzyme, RuBisCO, catalyzes a reaction with CO 2 and another molecule, RuBP. Which of the following does not occur during cyclic photophosphorylation in cyanobacteria? Whole processes of photosynthesis have been broadly divided into light reaction and dark reaction. The reaction center contains a pigment molecule that can undergo oxidation upon excitation, actually giving up an electron. During the light-dependent reactions, which molecule loses an electron? It consists of light-dependent and light-independent reactions. In photosynthesis, carotenoids function as photosynthetic pigments that are very efficient molecules for the disposal of excess energy. Calvin cycle is the light-independent reaction that takes place in the stroma of mitochondria. Part of our Photosynthesis Learning Guide. Light reactions of photosynthesis are light dependent reactions. In the light-dependent reaction s , energy from sunlight is absorbed by pigment molecules in photosynthetic membranes and converted into stored chemical energy. 6 marks light-dependent reaction: 3 max chlorophyll absorbs light (energy)/photons electron activated/excited electron passed down electron carriers ATP produced NADP+ reduced/ reduced NADP produced/ NADPH produced light-independent reaction: 3 max CO2 fixed by/reacts with 5C molecule … Light independent reactions depend on light dependent reaction for supply of APT, NADPH. The light-dependent reactions of photosynthesis occur in the thylakoid membrane of the chloroplast in a plant cell. Cellular respiration. Light-Dependent Reactions H20 Light-Independent Reactions Plants absorb carbon from the atmosphere and complete the process of photosynt For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. If a cell’s need for ATP is significantly greater than its need for NADPH, it may bypass the production of reducing power through cyclic photophosphorylation. These reactions occur in the stroma, the fluid-filled area of a chloroplast outside of the thylakoid membranes. In light-dependent reactions, the energy from sunlight is absorbed by chlorophyll and converted into chemical energy in the form of electron carrier molecules like ATP and NADPH. The light-dependent reaction produces ATP and NADPH. If the cell requires both ATP and NADPH for biosynthesis, then it will carry out noncyclic photophosphorylation. Question: Question 10 Of 17 Which Statements Describe The Light-dependent Reactions Of Photosynthesis, Which Describe The Calvin Cycle (light-independent Reactions Of Photosynthesis), And Which Describe Both? Short animation describes the light independent reaction ( carbon fixation that occurs during the light-independent reactions ; light-dependent. 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