Pick the incorrect statement

The correct option is: "mitochondria and chloroplasts both have an internal compartment, the thylakoid space bound by thylakoid membrane".

To understand why this statement is incorrect, let us examine the structure of both mitochondria and chloroplasts step-by-step:

1. Structure of Chloroplasts:
Chloroplasts are double-membrane-bound organelles found in plant cells and algae. Inside the inner membrane of a chloroplast, there is a fluid-filled space called the stroma. Suspended within the stroma is a third membrane system consisting of flattened sacs called thylakoids. The thylakoid membrane encloses a single, continuous internal compartment known as the thylakoid space (or lumen). Thus, thylakoids and the thylakoid space are unique features of chloroplasts.

2. Structure of Mitochondria:
Mitochondria are also double-membrane-bound organelles, but they do not possess a thylakoid membrane system. Instead, the inner membrane of a mitochondrion is folded into numerous finger-like projections called cristae, which enclose a fluid compartment called the matrix. The space between the outer and inner membranes is the intermembrane space. Mitochondria completely lack thylakoids and a thylakoid space.

Analysis of the other options to confirm their correctness:
• "generally, chloroplasts are larger than mitochondria": This is a correct statement. Chloroplasts typically measure about 5 to 10 µm in length, whereas mitochondria are generally smaller, ranging from 1 to 10 µm in length but usually much thinner (about 0.5 to 1 µm in width).
• "mitochondria and chloroplasts both have DNA": This is a correct statement. Both organelles are semi-autonomous and contain their own circular DNA molecules, along with ribosomes, allowing them to synthesize some of their own proteins.
• "mitochondria and chloroplasts both contain an outer and inner membrane": This is a correct statement. Both organelles are envelope-bound with two distinct lipid bilayer membranes (an outer membrane and an inner membrane).

Therefore, because mitochondria do not contain thylakoids or a thylakoid space, the statement claiming that both organelles possess this compartment is incorrect, making it the correct choice for this question.