A virus is a small infectious agent that can replicate only inside the living cells of an organism. Virology is the study of viruses.

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It is possible for person with AIDS be negative for HIV antibodies?

I'm just curious as there was a bit controversy around this topic. It is possible for person with AIDS be negative for HIV antibodies? As of 1989, the CDC reported that 5% of all U.S. AIDS patients ...
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Can viruses that normally infect eukaryotic cells also infect bacteria?

Can standard viruses infect bacteria? I'm not speaking of bacteriophage but typical RNA and DNA virus such as influenza and Ebola.
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How do I interpret this graph regarding introduced genes and virus-infected cells?

This graph appeared in a practice test for the MCAT. I am trying to interpret it, but it confuses me a bit. On the x-axis we have some introduced genes, and on the y-axis we have % of cells ...
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Theoretically, what technique would one use to modify a virus so that it only affected a subset of the population?

I'm writing a novel and i would like to know some of the equipment and techniques involved with modifying a virus. Is it feasible for a virus to be engineered to only affect certain people? It ...
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Is there an 'anti-virus'?

A virus spreads around and usually attaches itself to the host, multiplies & causes diseases. But is there something like an anti-virus? A single celled entity that does the opposite: spreads ...
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Do Noroviruses include many families?

Wikipedia says Caliciviridae Family. My notes say that Norovirus includes the following Noroviruses Norwalk-like viruses Caliciviruses Astroviruses and some small gastroenteroviruses which is a ...
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Why don't warts caused by HPV spread to the whole body?

My son had a plantar wart on his foot, which (as I understand it) is caused by a virus which only infects skin cells. Once in the skin cell the virus replicates, but when attacked by the immune system ...
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125 views

How does the MMR vaccine affect lymph nodes in preventing measles?

I am trying to understand this statement about the Measles part of the MMR (Mumps, Measles and Rubella) vaccine Measles prevention: MMR (AB protect during primary and secondary viremia) Measles ...
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What do viruses do during incubation period?

For example, there is an incubation period of around 1 to 3 days for common cold, and that of AIDS can range over to decades. What do viruses do actually do during the incubation period? What ...
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Restriction endonucleases are found in?

Quoting from : Scientific American July 1975 The Manipulation of genes by Stanley Cohen : Restriction endonucleases (and modification methylases) are widespread in microorganisms; genes for ...
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Tc and Th1 interaction and viral immune response

Tc is T cell which can give T killer cells and T helper cells. T helper cells (Th1) see the pathogen presented by antigen presenting cells (dendritic cells and macrophages). They then secrete antigens ...
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Size of DNA in phage

I have read that DNA(after recombination) is packaged in bacteriophages lambda only if it's between 40000 and 53000 bp long. This constraint can be used to ensure packaging of recombinant DNA. I ...
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How does the ebola virus attack?

How does the ebola virus attack and how do some people get away with it? Normally any virus would attack a cell with some kind of receptors and some kind of lock and key mechanism entering the cell ...
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Viruses: Adaptation to a new host through repeated host jumps

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly ...
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9k views

Why does rabies cause hydrophobia?

What feature of rabies pathophysiology causes hydrophobia? Why is hydrophobia unique to this one particular type of viral infection?
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118 views

Effect of nerve pills and relationship to Shingles [closed]

Do nerve pills actually suppress the nervous system and how would that effect the Shingles virus which is known to activate under large amounts of stress?
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620 views

Why does methylation not occur in viral DNA?

Why does methylation not occur in viral DNA? Can viral DNA undergo the process of methylation? If not then why does this process does not occur in viruses?
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Property of E.coli harboring F element

From Genetics by Ursula Goodenough E.coli harboring an F element are endowed with a number of phenotypic traits : 1.They are sensitive to infection by ssRNA phages and certain ssDNA phages. ...
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259 views

What is the biological reason that some viruses cause sore joints (eg flu)?

Frequently I have experienced sore joints during a bad bout of influenza. I understand that during time of sickness, white blood cells are deployed in the blood stream. I also believe that white blood ...
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62 views

Why can't my body deal with cold-sores

I am not a biologist, but I have always wondered why my body hasn't learnt to deal with the HSV-1 virus. I understand it reamins dormant for a while and things like stress or the common cold can ...
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108 views

Epithelial cells and Rhinovirus

If you injected a tumor with epithelial cells infected with the Rhinovirus, would this still evoke an immune response as it would with the respiratory system? Secondly, what is the specific reason the ...
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38 views

Which inflammatory response with Cytomegalovirus infection?

I am thinking about inflammation process with Cytomegalovirus infection. I first thought it is about chronic inflammation, but then changed my mind because of virus infection. I think cytokines must ...
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How do a viruses or bacteria survive outside the body long enough to spread?

Say I cough on my table, then someone else touches it and picks up something I've got... how is it that these things can live outside the body, how long can they manage it, and how long is generally ...
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How do wild animals get rabies?

I can see the chain of spreading disease: Humans usually get rabies from domestic animals, those usually get it from wild animals, wild animals in their turn get from the other wild animals and here ...
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Is it impossible for a retrovirus to be lysogenic?

Is it impossible for retroviruses to be lysogenic? In the lysogenic cycle, the viral genetic material is incorporated into the host cell's DNA. Because retroviruses have RNA, it would be impossible ...
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In the lysogenic cycle, does the provirus split from the cell's main genetic material for replication?

In a diagram of the lysogenic cycle sent by my instructor in a video, it shows the provirus splitting from the cell's main DNA when the dormancy period ends and the viral DNA is "activated". Is this ...
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What happen's to a virus's capsid after it injects its genetic material into the host cell?

After a virus (one of the varieties which infects the cell via injection and not endocytosis) injects its genetic material into the host cell, what happens to its protein coat? I would guess that it ...
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Do lysogenic viruses only infect bacteria?

In the video sent by my teacher on viruses, the example he used for lysogenic viruses was a bacteriophage infecting a bacteria. When he was describing how the genetic material was incorporated into ...
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Lytic Viruses — Cell lysis?

So in the video my instructor sent on viruses, he said that for lytic viruses, new viruses manufactured by the host cell could get out of the cell in one of two ways. The new viruses would leave by ...
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Are viruses self-propelled?

So obviously, viruses are nonliving. But when my teacher was teaching viruses in the video (we're doing "flip" learning this semester), the way he described it, it seemed like the viruses responded to ...
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How are viruses weakened to be suitable for vaccination?

I understand there are two kinds of active vaccination Injecting complete viruses that are weakened to not cause the disease being vaccinated against Injecting only antigen particles of viruses that ...
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Mutation rate in viruses

Mutation rate is a phenotypic trait that evolves. The process of evolution of such kind of traits are often referred to as evolvability. I am wondering about the evolution of the mutation rates in ...
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What would happen if you combined the world's deadliest diseases & viruses?

What would happen if you took the deadliest diseases/viruses in the world and combined them in a single medium (a solution of water or a test subject)? Would the strongest virus defeat the rest or ...
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Healing rate of cut while suffering from a cold

I recently cut my finger fairly deeply with a box cutter and had to have it stitched. During the healing process I contracted a strong cold/mild flu (a sore throat and runny nose with a high fever, ...
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104 views

How does a prophage leave the host cell's genome?

I understand that, unlike a prophage, a provirus never leaves the genome, but I don't understand how the prophage "leaves".
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Examples of virus originated from a living system

Do you know some examples of virus or a viroid (or a prion) that originated from a known living organism? How does the virus/viroid/prion lives? Does it paratize the organism from which the virus ...
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How is RNA of retrovirus converted into cDNA?

The retrovirus (oncovirus) contains RNA. It also has a molecule called reverse transcriptase. This molecule transcribes RNA into cDNA. This cDNA is the DNA copy of viral RNA genome RNA has Uracil ...
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Changing the definition of life?

Viruses at this period of time do not fit the current definition of life. Much of the reasoning behind this is that we currently believe that all life must be made up of cells. Also, many ...
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How did viruses learn to utilize the workings of a cell?

This is my first post here, so excuse me for its simplicity. Viruses can infiltrate a cell, overtake it and multiply. It has projecting fibers whose ends are shaped as kind of a "key" to a mobile ...
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How effective are restriction enzymes in protecting bacteria?

Bacteria use restriction enzymes to cut DNA of bacteriophages. Virus mutates really fast. Won't a point mutation in restriction site render the restriction enzymes of the bacteria useless ? So how ...
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Why restriction enzymes cut (usually) at palindromic sequences?

Restriction enzymes usually cut only at palindromic sequences. Is there any specific reason for that ? Is there any advantage for bacteria if it cuts up virus at this type of sequences ?
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What is the advantage of restriction enzymes cutting only at specific sites?

Bacteriophages have sequences which often do not have specific sites for restriction enzymes of bacteria to cut at and so can attack the bacteria. Wouldn't it be better if bacteria had something ...
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What decides whether a lysogenic cycle or a lytic cycle will take place?

A virus can either participate in a lysogenic cycle or a lytic cycle. What decides that?
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Can viruses protect themselves against restriction enzymes?

Restriction enzymes cut the DNA of bacteriophages. Have bacteriophages evolved any mechanism to protect themselves from it ?
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2k views

When can a virus modify DNA in every cell of a living organism?

I've recently heard about experiments with brain tissue, where a virus is introduced in a rats brain, causing a "glow when electric charge is present" protein to be created. This protein then helps to ...
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Why isn't a virus “alive”?

The recent news about a new supermassive virus being discovered got me thinking. What biological differences between viruses and cellular organisms have made viruses be deemed non-living?
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How does a virus take control over the host cell?

When the virus integrates its DNA with the hosts and enters the lytic pathway, do the viral proteins that produced destroy the cells DNA? Do they deactivate it? Also does the cell function in the same ...
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Why is herpes virus neurotropic?

A neurotropic virus is a virus which capable of infecting nerve cells. Herpes simplex virus (HSV) has low neuroinvasivesess and high neurovirulence. HSV is transmitted in vesicle fluid, saliva and ...