Question

Assertion:
Mitochondria and chloroplast are semiautonomous organelles.
Reason:
They are formed by division of preexisting organelles as well as contain DNA but lack protein-synthesizing machinery.

A. Both assertion and reason are correct and the reason is the correct explanation for the assertion.
B.Both assertion and reason are correct but the reason is not the correct explanation for the assertion.
C. Assertion is correct but the reason is incorrect.
D. Both assertion and reason are incorrect.

Answer 1

Mitochondria and chloroplasts are called semi-autonomous cell organelles as they have their own DNA and ribosomes. Therefore, they can synthesize some of their proteins. For other proteins, they are dependent on the nucleus.

Complete step by step answer: Mitochondria are cell organelles found in large numbers in cells.
They contain their own DNA that can replicate independently and can also produce its own ribosomes and have the ability for protein synthesis. These characteristics make the mitochondria semi-autonomous and not completely autonomous as the structure and the functioning of mitochondria are controlled by the nucleus of the cell and are dependent on the availability of materials from the cytoplasm. Similarly, like mitochondria, chloroplasts also contain their own DNA and reproduce independently, but these depend on the nuclear genome for the majority of the protein and enzyme requirements. They are inherited by the daughter cells during the cell division. Mitochondria are known as the powerhouse of the cell because it helps in the synthesis of ATP molecules. Chloroplasts are present only in animal cells and in algae. It has a green-coloured pigment called chlorophyll that helps in the process of photosynthesis.
Therefore, the correct answer is option C.

Note: Mitochondria break down fuel molecules and capture energy in the cellular respiration. It is a double-membrane bound organelle that has a matrix. Krebs cycle occurs in the matrix of the mitochondria. On the other hand, the chloroplast is also a membrane-bound organelle that consists of thylakoids, lamellae, etc.