Flashcards · Biology · Photosynthesis
The Photosynthetic Reaction
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Why are photosynthetic organisms the main producers of food?
They make organic compounds from carbon dioxide and water using light energy.
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What is biomass?
The mass of living material.
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What happens in the first stage of photosynthesis?
Light energy is absorbed by chlorophyll and used to split water, releasing oxygen.
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What happens in the second stage of photosynthesis?
Hydrogen from the water is used to fix carbon dioxide to make glucose.
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What is photosynthesis?
A reaction in which plants use light energy to make glucose from carbon dioxide and water.
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Write the word equation for photosynthesis.
Carbon dioxide + water, in light, makes glucose + oxygen.
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Write the symbol equation for photosynthesis.
6CO₂ + 6H₂O makes C₆H₁₂O₆ + 6O₂ (in light).
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What are the reactants in photosynthesis?
Carbon dioxide and water.
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What are the products of photosynthesis?
Glucose and oxygen.
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Why is photosynthesis an endothermic reaction?
It takes in energy from the environment, transferred by light.
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Where in the cell does photosynthesis take place?
In the chloroplasts.
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What does chlorophyll do?
It absorbs the light energy for photosynthesis.
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How does carbon dioxide get into a leaf?
By diffusion through the stomata.
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How does water get to the leaf?
It is taken up by the roots and carried up in the xylem.
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Where is the energy stored after photosynthesis?
In the glucose that is made.
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What is a producer?
An organism that makes its own food, such as a plant.
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How can you test a leaf for starch?
Kill and decolourise it, then add iodine solution, which turns blue-black.
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Why is the leaf boiled in ethanol?
To remove the chlorophyll, so the colour change can be seen.
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Name a gas that is a product of photosynthesis.
Oxygen.
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Name the substance marked X and say where it goes. Oxygen. It is a product of photosynthesis and leaves the leaf through the stomata.
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Label everything that goes into and comes out of the leaf. 
Light energy, carbon dioxide and water go in. Oxygen and glucose come out. Photosynthesis happens in the chloroplast.