Video Transcript
Which of the following tables
correctly matches structures within the chloroplast to the photosynthetic reaction
that occurs in each?
Chloroplasts are cell organelles
within plant cells that act as the site of photosynthesis. They have multiple specialized
structures within them, including stroma, thylakoids, and a double membrane. Each structure has a particular
function. But which structure is involved in
the light-dependent reaction and which is involved in the light-independent
reaction?
In the light-dependent stage, light
energy is absorbed by the plant and stored as usable energy. The thylakoid membranes contain
pigments, such as chlorophyll, that absorb light. A series of reactions then occurs
in which the light energy absorbed by the chlorophyll is stored in ATP
molecules. This means that the thylakoid
membrane is the site of the light-dependent reaction. This information indicates that the
table that correctly matches chloroplast structures to the photosynthetic reaction
is table (B). But let’s discuss where the
light-independent reaction happens, just to be sure.
In the light-independent stage of
photosynthesis, the energy stored in ATP is converted and used to form
carbohydrates. This occurs in the stroma, the
fluid matrix within the chloroplast that contains enzymes, which play a role in this
reaction. So, the correct answer is indeed
given by table (B). The thylakoid membranes are the
site of the light-dependent stage of photosynthesis, and the stroma is the site of
the light-independent reaction.
