SSC GD 2026 PYQ — Question 33

Correct Answer:

Mitochondria

Explanation:

Plastids (such as chloroplasts) and mitochondria share notable structural, functional, and evolutionary similarities. Both are double-membrane-bound organelles containing their own circular DNA, ribosomes, and machinery for protein synthesis. This unique characteristic supports the Endosymbiotic Theory, which suggests that both plastids and mitochondria evolved from free-living prokaryotes that were engulfed by ancestral eukaryotic cells.

Key Points:

Both mitochondria and plastids possess an inner and an outer membrane, giving them a similar double-membrane structural envelope.

Mitochondria are known as the "powerhouses of the cell" for generating ATP through cellular respiration, while plastids (like chloroplasts) are responsible for photosynthesis and storing food in plant cells.

Both organelles replicate independently within the cell through a process similar to binary fission.

Important Questions and Answers:

Question: Which cell organelles possess their own independent DNA apart from the nucleus?

Answer: Mitochondria and plastids.

Question: What scientific theory explains the origin of mitochondria and plastids having their own DNA and double membranes?

Answer: The Endosymbiotic Theory.