Which statement describes a gene versus a genome?

Which statement describes a gene versus a genome?

• A. A gene is the complete set of genetic material; a genome is a unit of heredity.
• B. A genome is coding DNA only; a gene is noncoding.
• C. A genome is found only in the nucleus.
• D. A gene is a unit of heredity; a genome is the complete set of genetic material.

Answer: (D)

Think about what each term means in genetics. A gene is a basic unit of heredity: a specific stretch of DNA that can be inherited and typically codes for a product such as a protein or RNA. A genome, on the other hand, is the entire set of genetic material in an organism or cell, including all genes plus the noncoding regions and any extra genetic material found in organelles like mitochondria. That makes the correct statement the best because it keeps the scope and function clear: a gene is a unit of heredity, while a genome is the complete set of genetic material. The other options mix up these ideas: saying a genome is coding DNA only ignores vast noncoding parts of the genome; claiming a genome is found only in the nucleus overlooks mitochondrial (and sometimes chloroplast) genomes; and reversing the definitions incorrectly assigns the complete set to a gene.

Think about what each term means in genetics. A gene is a basic unit of heredity: a specific stretch of DNA that can be inherited and typically codes for a product such as a protein or RNA. A genome, on the other hand, is the entire set of genetic material in an organism or cell, including all genes plus the noncoding regions and any extra genetic material found in organelles like mitochondria.

That makes the correct statement the best because it keeps the scope and function clear: a gene is a unit of heredity, while a genome is the complete set of genetic material. The other options mix up these ideas: saying a genome is coding DNA only ignores vast noncoding parts of the genome; claiming a genome is found only in the nucleus overlooks mitochondrial (and sometimes chloroplast) genomes; and reversing the definitions incorrectly assigns the complete set to a gene.