Photosynthesis

PHOTOSYNTHESIS TAKES PLACE IN THE CHLOROPLASTS OF PLANT CELLS

1) Chloroplasts are flattened organelles surrounded by a double membrane. 

2) Thylakoids (fluid-filled sacs) are stackd up in the chloroplasts into structures called grana (singluar = granum). The grana are linked together by bits of thylakoid membrane called lamellae.

3) Chloroplasts contain photosynthetic pigments (e.g. chlorophyll a, chlorophyll b and carotene). These are coloured substances that absorb the light energy needed for photosynthesis. The pigments are found in the thylakoid membranes - they're attached to proteins. The protein and pigment is called photosystem.

4) Two photosystems are used by plants to capture light energy. Photosystem I (PSI) absorbs light best at a wavelength of 700nm and photosystem II (PSII) absorbs light best at 680nm.

5) Contained within the inner membrane of the chloroplast and surrounding the thylakoids is…