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Learning to Learn

Nutrition in Plants: Photosynthesis

<h3>How plants feed themselves</h3><p>Plants are <strong>autotrophs</strong> &mdash; they manufacture their own food. They do this through <strong>photosynthesis</strong>, which happens mainly in the leaves where a green pigment called <strong>chlorophyll</strong> traps light energy from the sun.</p><h3>Raw materials and conditions</h3><ul><li><strong>Raw materials:</strong> water (taken up by roots) and carbon dioxide (taken in through tiny leaf pores called stomata).</li><li><strong>Conditions:</strong> light energy and chlorophyll.</li></ul><h3>The two stages</h3><p>In the <strong>light stage</strong>, light splits water molecules (photolysis), releasing oxygen and storing energy in a molecule called <strong>ATP</strong>. In the <strong>dark stage</strong>, the captured energy is used to join carbon dioxide and hydrogen into <strong>glucose</strong>.</p><p>The word equation is:</p><p><code>Carbon dioxide + Water &rarr; (light + chlorophyll) &rarr; Glucose + Oxygen</code></p><div class="callout"><strong>Kenyan context:</strong> The maize, tea and sukuma wiki grown on Kenyan farms all depend on photosynthesis. The oxygen these plants release helps keep our air breathable, and the glucose they store becomes the food on our plates &mdash; which is why protecting forests like Mau and the Aberdares matters so much.</div>
Audio narration — reads aloud, works offline

Which two raw materials are needed for photosynthesis?