Do viruses only replicate in host cells?
A virus is an infectious agent that can only replicate within a host organism. Viruses can infect a variety of living organisms, including bacteria, plants, and animals.
How does HIV virus replicate?
HIV cannot reproduce on its own. Instead, the virus attaches itself to a T-helper cell and fuses with it (joins together). It then takes control of the cell’s DNA, makes copies of itself inside the cell, and finally releases more HIV into the blood.
How does HIV replicate in a host?
When HIV infects a cell, it first attaches to and fuses with the host cell. Then the virus uses the host cell’s machinery to convert the viral RNA into DNA and replicate itself. The new copies of HIV then leave the host cell and move on to infect other cells.
What cells do viruses replicate in?
Most DNA viruses assemble in the nucleus; most RNA viruses develop solely in cytoplasm. Viral populations do not grow through cell division, because they are acellular. Instead, they hijack the machinery and metabolism of a host cell to produce multiple copies of themselves, and they assemble inside the cell.
How do RNA viruses replicate in host cells?
RNA viruses replicate their genomes via one of two unique pathways—either by RNA-dependent RNA synthesis, or among the retroviruses, by RNA-dependent DNA synthesis (reverse transcription) followed by DNA replication and transcription.
How often do viruses replicate?
The reproductive cycle of viruses ranges from 8 hrs (picornaviruses) to more than 72 hrs (some herpesviruses). The virus yields per cell range from more than 100,000 poliovirus particles to several thousand poxvirus particles.
What did the virus use on the host cell in order to make contact with and gain access to the cell?
Attachment. A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
How do viruses replicate in host cells?
Viruses cannot replicate on their own, but rather depend on their host cell’s protein synthesis pathways to reproduce. This typically occurs by the virus inserting its genetic material in host cells, co-opting the proteins to create viral replicates, until the cell bursts from the high volume of new viral particles.
How do viruses attach themselves to host cells?
A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
How do ssDNA viruses replicate?
Most ssDNA viruses contain circular genomes that are replicated via rolling circle replication (RCR). ssDNA RCR is initiated by an endonuclease that bonds to and cleaves the positive strand, allowing a DNA polymerase to use the negative strand as a template for replication.
How does HIV enter cells?
HIV infects white blood cells in the body’s immune system called T-helper cells (or CD4 cells). The virus attaches itself to the T-helper cell; it then fuses with it, takes control of its DNA, replicates itself and releases more HIV into the blood.
What is the origin of the HIV virus?
The origin of the Aids pandemic has been traced to the 1920s in the city of Kinshasa, in what is now the Democratic Republic of Congo, scientists say. An international team of scientists say a “perfect storm” of population growth, sex and railways allowed HIV to spread.
Is AIDS bacteria or virus?
HIV is an infection that can lead to AIDS. HIV stands for Human Immunodeficiency Virus. It’s a virus that breaks down certain cells in your immune system (your body’s defense against diseases that helps you stay healthy).
What is the receptor for HIV?
HIV virus particles interact with several receptors on cell surfaces. Two receptors, CD4 and a co-receptor act sequentially to trigger fusion of viral and cellular membranes and confer virus entry into cells. For HIV-1, the chemokine receptor CCR5 is the predominant co-receptor exploited for transmission and replication in vivo.