In Lesson 1 you studied the chloroplast and learned to identify its structures and functions. As you begin to explore the light-dependent reactions of photosynthesis, you will
be focusing on the reactions that happen in the
thylakoid membrane.
The flattened thylakoids in the chloroplasts of plant cells are stacked into columns called grana. Surrounding the thylakoids and filling the interior of the chloroplast is the fluid stroma, which is where the chemical reactions that synthesize
carbohydrates take place.
Chlorophyll is the light-capturing pigment that absorbs all wavelengths of light except for green and some yellow.
Chlorophyll a absorbs more indigo, violet, and red wavelengths. Chlorophyll b absorbs more blue and orange wavelengths. Beta carotene absorbs violet, indigo, blue, and green wavelengths, but not yellow, orange, or red wavelengths.
Refer to the D portion of Figure 5.9 on page 171. Oxygen production is the lowest between 500 and 550 nm (green-light wavelength). Oxygen production is highest between 400 and 475 nm (indigo/blue-light wavelengths).