NEETBotanyCell - The Unit of Life
A plant cell contains certain double membrane-bound organelles that are excluded from the endomembrane system but possess their own protein-synthesizing machinery. Which of the following features is common to these specific organelles?
Options
- APresence of 80S ribosomes in their internal compartment
- BThey contain circular DNA molecules and 70S ribosomes
- CTheir inner membrane is highly folded into structures called cristae
- DTheir inner membrane encloses flattened membranous sacs called thylakoids
Correct answer
B. They contain circular DNA molecules and 70S ribosomes
Step-by-step solution
The double membrane-bound organelles in a plant cell that are excluded from the endomembrane system and possess their own protein-synthesizing machinery are mitochondria and plastids (chloroplasts). Both mitochondria and chloroplasts are semi-autonomous organelles. They contain their own circular DNA molecules and 70S ribosomes, which allow them to synthesize some of their own proteins. Option 1 is incorrect because they contain 70S (not 80S) ribosomes. Option 3 is incorrect because cristae are found only in mitoch