Lesson Summary:
Chloroplasts are the organelles responsible for photosynthesis, mainly found in the mesophyll cells of leaves. They contain a double membrane, internal thylakoid membranes that form grana, and a fluid-filled stroma. Thylakoid membranes hold pigments like chlorophyll a, chlorophyll b, and carotene, which absorb light for the light-dependent stage. Pigments form photosystems that funnel energy to a reaction center where electrons are energized for photosynthesis.

Three Things Students Must Learn:

  1. Chloroplast structure includes membranes, thylakoids, grana, stroma, and DNA.

  2. Photosynthetic pigments absorb specific light wavelengths to power photosynthesis.

  3. Photosystems (I and II) organize pigments to capture and transfer light energy to chlorophyll a.