Questions and Answers
Is photosynthesis an endergonic or exergonic reaction and why?
Photosynthesis is an endergonic reaction because it absorbs energy from the sun. It is adding energy into the plant.
What is the main pigment used by green plants to absorb energy?
Chlorophyll
Which wavelengths of light are best absorbed by chlorophyll a & b?
Blue and red
Which wavelengths of light are reflected by chlorophyll a & b?
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How are carotenoid pigments different from chlorophyll?
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Why do plants look green?
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Where do the light dependent reactions take place (chlorophyll is also located here)?
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Where do the light independent reactions Calvin cycle/dark reactions take place?
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What are the reactants and the products of the light-dependent reactions?
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What are the reactants and the products of the dark reactions/Calvin cycle?
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What is a photoreceptor?
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The use of light to split H2O is called...
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Photosystem II is also referred to as...
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Photosystem I is also referred to as...
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When light strikes the photosystems, it excites the electrons and they move out of the photosystems to a higher energy state and then move down the ___________
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As they move down the electron transport chain (from a higher energy molecule to lower energy molecules) _______ is released.
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This released energy is used to pump ________ against the gradient (from low to high concentrations). This is a type of _______ transport because it uses energy.
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These protons are then pumped through ATP synthase to make _______
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The electrons from Photosystem II move down the ETC and enter __________
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The electrons from Photosystem I move down the ETC and are accepted by the last electron acceptor molecule called _______
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What are the three molecules that water is split into during photolysis?
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The electrons from water being split move into __________
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The oxygen from water being split is _________ back into the atmosphere.
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_______ and _______ are considered metabolic intermediates because they are products of the light reactions and are used as reactants in the dark reactions.
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Write the chemical equation for photosynthesis.
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Is cellular respiration an endergonic or exergonic reaction and why?
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Why do plants have these other pigments besides chlorophyll?
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Study Notes
Photosynthesis Overview
- Photosynthesis is an endergonic reaction, absorbing energy from sunlight to fuel plant processes.
- Main pigment for energy absorption in green plants is chlorophyll.
Light Absorption
- Chlorophyll a and b absorb blue and red wavelengths of light effectively.
- Chlorophyll reflects green light, making plants appear green.
- Carotenoid pigments absorb blue, purple, and green light, but reflect red, orange, and yellow, contributing to autumn leaf colors.
Reaction Locations
- Light-dependent reactions occur in thylakoids, where chlorophyll is located.
- Light-independent reactions (Calvin cycle) take place in the stroma.
Light-Dependent Reactions
- Reactants: light and H2O; products: O2, ATP, NADPH.
- Photolysis refers to the use of light to split water (H2O) into protons, electrons, and oxygen.
- Photosystem II (P680) and Photosystem I (P700) are involved in capturing light energy and transferring electrons through the electron transport chain (ETC).
Electron Transport Chain
- Excited electrons move down the ETC, releasing energy as they transition to lower energy states.
- This energy is used to pump protons against their gradient, a form of active transport.
- Protons flow through ATP synthase to generate ATP.
Light-Independent Reactions
- Reactants: CO2, ATP, NADPH; products: glucose (C6H12O6), ADP + P, NADP+.
- ATP and NADPH are metabolic intermediates, produced during light reactions and utilized in dark reactions.
Chemical Equation
- The chemical equation for photosynthesis is:
- 6CO2 + 6H2O + energy → C6H12O6 + 6O2.
Cellular Respiration Comparison
- Cellular respiration is exergonic, releasing ATP as energy.
- Other pigments like carotenoids extend the lifespan of leaves by providing color change before they die.
Key Facts
- Photoreceptors in plants include chlorophyll and carotenoids for receiving light.
- Oxygen released during photolysis is returned to the atmosphere as a byproduct.
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Description
Test your knowledge on photosynthesis with these flashcards. Explore concepts such as the nature of the reaction, the primary pigment involved, and the wavelengths of light significant for chlorophyll absorption. This quiz is perfect for students looking to deepen their understanding of plant biology.