compare and contrast a provirus and viral DNA
A: a provirus is newly replicated viral DNA after injection
B: a provirus is bacterial DNA incorporated into the viral DNA
C: a provirus is the host cells DNA that has been destroyed
D: a provirus is a viral DNA incorporated into the host cells DNA
The correct answer is D: a provirus is a viral DNA incorporated into the host cell's DNA.
A provirus refers to the DNA form of a virus that has integrated into the genome of the host cell. It is mainly associated with certain types of viruses, such as retroviruses. This integration occurs through the action of reverse transcriptase, an enzyme that converts the viral RNA into DNA. Upon integration, the provirus becomes a permanent resident in the host cell's genome.
On the other hand, viral DNA generally refers to the genetic material of a virus, which can come in various forms, such as single-stranded or double-stranded DNA. Viral DNA can exist outside the host cell as an extrachromosomal element or be integrated into the host cell's genome. However, viral DNA is not always referred to as a provirus, as this term specifically indicates the integration of viral DNA into the host cell's DNA.
The correct answer is D: a provirus is a viral DNA incorporated into the host cells DNA.
Here is a step-by-step comparison and contrast between a provirus and viral DNA:
1. Definition:
- A provirus is a form of viral DNA that has been inserted into the host cell's genome.
- Viral DNA refers to the genetic material of a virus that contains the necessary instructions for virus replication and assembly.
2. Origin:
- Provirus: It is formed when the DNA of a virus integrates into the DNA of a host cell.
- Viral DNA: It is a component of the virus itself, and it is derived from the replication of viral genetic material within infected cells.
3. Formation:
- Provirus: It occurs when the viral DNA is integrated into the host cell's DNA, becoming a permanent part of the cell's genome.
- Viral DNA: It is the result of viral replication and can exist as a separate entity within a virus particle.
4. Presence and Activity:
- Provirus: Once integrated, the provirus remains latent within the host cell's DNA. It may not always be actively producing new viral particles or causing disease.
- Viral DNA: It is present within the virus particle and is responsible for initiating viral replication and the production of new viral particles upon infecting a host cell.
5. Transmission:
- Provirus: It can be transmitted vertically from one generation to the next as the host cell divides and transfers its genetic material.
- Viral DNA: It is transmitted horizontally from one host to another through various means, such as direct contact or via vectors like mosquitoes.
6. Impact on the Host:
- Provirus: It can have long-term effects on the host cell's biology, potentially leading to alterations in gene expression or causing disruptions in cellular processes. It may also act as a reservoir for future virus production.
- Viral DNA: It directly influences the replication and assembly of new virus particles within infected cells, ultimately leading to the production of viral progeny and potential harm to the host.
In summary, while viral DNA refers to the genetic material of a virus, a provirus is a specific type of viral DNA that has become integrated into the host cell's DNA.
The correct answer is D: a provirus is a viral DNA incorporated into the host cells DNA.
A provirus is formed when a virus infects a host cell. During infection, the viral DNA is integrated into the host cell's DNA. This means that the viral DNA becomes a permanent part of the host cell's genetic material. The provirus can remain in a dormant state within the host cell's DNA for an extended period, occasionally becoming active and producing new viruses.
Now, let's compare and contrast a provirus and viral DNA:
Similarities:
- Both a provirus and viral DNA are forms of genetic material.
- Both a provirus and viral DNA can contain the complete genetic information needed for viral replication.
- Both a provirus and viral DNA can be passed on to daughter cells during cell division.
Differences:
- A provirus is the incorporation of viral DNA into the host cell's DNA, while viral DNA exists separately from the host cell's DNA.
- Viral DNA can be present in different forms, such as double-stranded DNA or single-stranded RNA, depending on the type of virus, whereas a provirus is always a form of DNA.
- Viral DNA is typically the genetic material of a complete virus particle, whereas a provirus is the integrated viral DNA within a host cell.
In summary, a provirus is an integrated form of viral DNA into the host cell's DNA, allowing the virus to persist in a dormant state within the host cell. On the other hand, viral DNA is the genetic material of a virus that can exist independently outside the host cell.