Question

Which statements about viruses are true?

1. All RNA-containing viruses are retroviruses.
2. HIV contains two identical strands of DNA.
3. All viral genomes contain both DNA and RNA.
4. The capsid enters the host cell if the virus is enveloped.
5. HIV contains reverse transcriptase.
6. Enveloped viruses bud from the host cell.
7. A retrovirus contains RNA.

Answer 1

Of the statements about viruses, numbers 4, 5, 6, and 7 are true. Statements 1, 2, and 3 are false: not all RNA viruses are retroviruses, HIV contains RNA not DNA, and viral genomes contain either DNA or RNA, but not both.

Step-by-step explanation:

Addressing the statements about viruses and providing clarification:

1. All RNA-containing viruses are retroviruses. This statement is false. Not all RNA viruses are retroviruses; only those that replicate through a DNA intermediate using reverse transcriptase are classified as such.
2. HIV contains two identical strands of DNA. This statement is incorrect. HIV, a retrovirus, contains two identical strands of RNA, not DNA.
3. All viral genomes contain both DNA and RNA. This statement is false. Viral genomes either contain RNA or DNA, but never both simultaneously.
4. The capsid enters the host cell if the virus is enveloped. This is true; in enveloped viruses, the capsid, along with the viral genetic material, enters the host cell during infection.
5. HIV contains reverse transcriptase. This statement is true. HIV, being a retrovirus, uses reverse transcriptase to convert its RNA genome into DNA within the host cell.
6. Enveloped viruses bud from the host cell. This statement is true; enveloped viruses acquire their membrane from the host cell as they bud out, taking a portion of the host cell membrane with them.
7. A retrovirus contains RNA. This statement is true. Retroviruses such as HIV have an RNA genome that is reverse-transcribed into DNA.