« on: 11/05/2018 13:49:50 »
This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
Somehow I missed this post the first time, so here I am, a decade later, answering the question! I hope @neilep you're not too frustrated by the wait. But look on the bright side, people have spent longer on hold on the phone trying to cancel their direct debit with Eon, HMRC or BT...
Viruses are obligate intracellular parasites. In plain English, they are infectious packets of genes that require a living cell to provide key functions that they lack so that they can replicate and increase their numbers.
Viruses come in many different shapes and sizes, both literally, and metaphorically. Some are absolutely tiny: particles of norovirus, which is one of the commonest causes of diarrhoea and vomiting, are just 30nm - 1/30,000th of a millimetre - across. Other viruses are enormous in comparison. The recently-discovered mamaviruses, pithoviruses and pandoraviruses are so large that there were initially mistaken for bacteria, which are usually orders of magnitude bigger than a virus.
This broad diversity, and the fact that viruses target every living entity on Earth including even other viruses (there are viruses that prey on viruses: these are called virophages), suggests that they have been around for a very long time and may even predate modern multicellular life itself.
One theory of the origin of viruses posits that they were initially a spin-off from the first cells. Genetic functions that had evolved to replicate themselves escaped the confines of their parent cell and became independent entities that nevertheless came home to roost in the cell to replicate but otherwise had little else in common.
Other hypotheses even regard some viruses as the origin of life on Earth.The giant viruses mentioned above (gyruses) contain such a broad repertoire of genes that cross all three of the main kingdoms of life, and also even include genes not seen in any living species, suggests that perhaps these entities gave rise to us all from the primordial soup.
The bottom line is that viruses contain an assemblage of genes that enable them to freeload off living cells, which they hijack by first fooling the cell into allowing them in, and then assimilating by using genetic tricks that can deactivate all but the most essential and useful cellular systems to enable the virus to grow rapidly, or they do the opposite and deactivate themselves so that they can lurk undetected within the genetic recesses of the cell, either by pretending to be a miniature chromosome that the cell ignores, or inserting themselves inside the host cell's own DNA. In both cases they end up immunologically "off grid".
But, next time you are sneezing into a hanky having fallen prey to another rhinovirus infection, you can take some solace from the fact that this is not a modern problem. Genetic analysis confirms that dinosaurs had herpes! More a case of T-sex than T-rex, perhaps...
I'm flagging a bit, feel all at sea.
Another phenomenon noticed about tip-of-the-tongue(TOT) problem.Remember the toy "Magic 8-Ball"?The answer floated up into a window.The brain does something similar.If the word won't come to you,back off and relax,still intending to think of the word eventually.The brain,somewhere behind the scenes,will often do a retrieval later,a half hour or whatever.The answer will suddenly come to mind consciously.An alternate,slower path has been used to accomplish the same task.