Solution

Extranuclear (cytoplasmic) inheritance is inheritance through genes located outside the nucleus.
Mitochondria and chloroplasts are semi-autonomous organelles. They contain their own circular double-stranded DNA, ribosomes and machinery for protein synthesis.
These organelles pass to the next generation mainly through the cytoplasm of the egg, so such traits show maternal inheritance (e.g. leaf variegation in Mirabilis jalapa, studied by Correns).
Endoplasmic reticulum, lysosomes and ribosomes do not contain genes (DNA).
So extranuclear inheritance is due to genes present in mitochondria and chloroplasts.

Concept DNA in mitochondria and plastids

Principles of Inheritance and Variation in past papers

198 questions from this chapter have appeared across 27 exam years.