Question

which is true concerning chloroplasts?
select all that apply
a the calvin cycle occurs in the stroma.
b the light reactions occur in the thylakoid membranes.
c each chloroplast contains stacks of thylakoids called grana.
d the thylakoid membranes contain photosystems.

Explanation:

• Option a: The Calvin cycle (light - independent reactions) occurs in the stroma of the chloroplast. It uses ATP and NADPH (produced in the light reactions) to fix carbon dioxide.
• Option b: The light reactions occur in the thylakoid membranes. These membranes contain photosystems (PS I and PS II) which capture light energy.
• Option c: Chloroplasts have stacks of thylakoids called grana. Each granum is a stack of disc - shaped thylakoids.
• Option d: The thylakoid membranes contain photosystems (PS I and PS II). These are protein - pigment complexes that play a crucial role in the light reactions of photosynthesis.

Answer:

A. The Calvin cycle occurs in the stroma.
B. The light reactions occur in the thylakoid membranes.
C. Each chloroplast contains stacks of thylakoids called grana.
D. The thylakoid membranes contain photosystems.