Which of the following does not possess both DNA and RNA:
**Core Concept**
Mitochondria, viruses, and bacteria are cellular entities that possess their own genetic material, but not all of them have both DNA and RNA. This question tests the student's understanding of the genetic composition of various cellular components.
**Why the Correct Answer is Right**
Mitochondria possess their own DNA (mtDNA), but it does not code for the majority of mitochondrial proteins. Instead, these proteins are encoded by nuclear DNA and then imported into the mitochondria. Mitochondria do, however, have their own RNA, including tRNA and rRNA, which are essential for protein synthesis within the mitochondria. Viruses and bacteria, on the other hand, do possess both DNA and RNA, with viruses using either DNA or RNA as their genetic material and bacteria possessing both DNA and RNA.
**Why Each Wrong Option is Incorrect**
**Option A:** Viruses do possess both DNA and RNA, depending on the type of virus. Some viruses, such as HIV, use RNA as their genetic material, while others, like herpes simplex virus, use DNA.
**Option B:** Bacteria possess both DNA and RNA, with DNA serving as their primary genetic material and RNA playing a crucial role in protein synthesis.
**Option C:** Viruses and bacteria both possess both DNA and RNA, making them incorrect options.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that mitochondria have their own genetic material (mtDNA), but it is limited in coding for proteins, whereas viruses and bacteria have a broader genetic capacity.
**Correct Answer:** C.