AIIMS 2001 Botany Mitochondrial Inheritance MCQ Question

Extranuclear genes, also known as cytoplasmic genes, are found in organelles such as mitochondria and plastids. These genes are inherited differently than nuclear genes. The correct answer is C) mitochondria - and inherited by female. This is because mitochondrial DNA is passed from mother to offspring, as the mitochondria in sperm are typically destroyed after fertilization.

Option A) plastids - and not inherited is incorrect because plastids, like chloroplasts, do contain extranuclear genes, but they are generally inherited maternally in plants.

Option B) plasmid - and not inherited is misleading; plasmids are small circular DNA molecules found in bacteria and are not considered extranuclear genes in the context of eukaryotic organelles. They can be inherited, but this is not the focus of the question.

Option D) mitochondria - and inherited by male is incorrect as mitochondrial DNA is inherited exclusively from the mother. Therefore, the only correct statement is about mitochondria being inherited by females.