Question

Consider the following statements
(a) Endomembrane system includes mitochondria, chloroplast and peroxisomes
(b) Smooth endoplasmic reticulum is a major site for synthesis of lipid
(c) Rough endoplasmic reticulum is actually involved in protein synthesis
(d) Mitochondrial matrix possesses single circular DNA, a few RNAs and 80 S ribosomes
Of the above statements ______________________.

• A. a and b alone are correct
• B. a and c alone are correct
• C. b and d alone are correct
• D. b and c alone are correct
• E. a and d alone are correct.

Answer 1

The correct option is D b and c alone are correct

• The endomembrane systemis a group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins. It includes a variety of organelles, such as the nuclear envelope and lysosomes, which you may already know, and the endoplasmic reticulum and Golgi apparatus.
• The functions of the mitochondria, chloroplasts and peroxisomes are not coordinated with the endoplasmic reticulum, Golgi complex, lysosomes and vacuoles. So they are not part of the endomembrane system.
• The smooth endoplasmic reticulum is the major site for the synthesis of the lipids and also it lacks the ribosomes whereas the rough endoplasmic reticulum is decorated with ribosomes and these are the sites of the protein synthesis.
• Mitochondrial matrix contains 70s ribosome, not 80s ribosome.

So the correct answer is option D.