This schematic shows shows a graphic representation of the structure of an HIV viron.  A viron is a single virus particle.  The actual "active" chemical molecules are the two ribbonlike copies of RNA protected inside the green capsid core shell, along with two copies of a protein molecule (the black balls labeled "protease, polymerase, RNAse, integrase").  The protein molecules have several functions once the virus penetrates into the host T cell, the major one being to jumpstart the process of viron replication.

 RNA is a mirror image of DNA, the material that genes are made from.  Once inside the host T cell, the "black ball" protein goes to work making multiple copies of viral DNA out of the two strands of viral RNA.  This process is called "reverse transcription" because it is the opposite of what usually happens in normal cells.  Generally, normal DNA molecules (the natural genes of the body) code for multiple copies of mirror image RNA which then goes fourth into the cell body to make protein molecules useful to the cell.

Instead, this new viral DNA creates more viral RNA. The new copies of viral RNA now hijack the host cell's "ribosomes", which are little protein factories that construct protein according to the instructions encoded in the viral RNA.  The new viral proteins are then organized into new virons which then escape the host cell taking with them an envelope of the host cell's own membrane as a protective envelope along with two copies of the newly manufactured RNA.  

In the lower left of this electron micrograph you can see a new viron budding off the membrane of an infected T cell.  If you look closely, you can also see that the cell membrane of the T cell is composed of two very thin parallel lines.  These lines are actually two interlaced molecules of phospholipids (called a bilayer) which is the common construction of all cellular membrane structure.  Note that when the viron buds off, it removes some of this host membrane structure for its own protection.  Within each viron, now encapsulated in its own stolen cellular membrane, lives the capsid which is a virus manufactured protein sheathe which houses the core viral RNA.

The image to the right shows the structure of a natural cell membrane.  It is composed of a pair of phospholipid chains which are arranged in such a way that the lipid portions face each other thereby avoiding contact with the aqueous (water based) surrounding medium.  For a better understanding of this structure, click on the image.

In the schematic at the top of the page, the red envelope is actually the stolen cell membrane.  The purple molecules lining it are a viral protein which stabilizes the membrane.  The dumbbell shaped molecules projecting outward from the membrane are specially manufactured "sugar" molecules called glucopolysacharides which are responsible for recognizing the correct host cell membrane and then attaching to it so it can begin the process of entering another host cell.  

HIV is in a broad category called "retroviruses" because it contains RNA as the infective molecule instead of DNA which is the stuff of other "normal" viruses.  The prefix "retro" means "reverse" and is a reference to the reverse transcription mentioned above.  

Aids

Copyright 2000 Martin S. Spiller, D.M.D.

All material on this web site is protected by copyright and is registered with the US Copyright office. All personal uses, including public and academic presentations, are permitted.  This fair use permission applies to oral and written reports, dissertations and theses for students in public and private schools, elementary and high schools, colleges and graduate schools.  It also applies to teachers wishing to print this material for classroom and course work.  Acknowledgement of this website as the source for this material during presentations is not required, but would be appreciated.  Any dentist or other professional who finds this material useful is welcome to print and distribute it to patients, or to refer their patients to this website.

Written requests for publication on the internet or other mass media (including printed publications) will be considered on a case-by-case basis.  Internet and printed publication IS permitted (without permission, but with attribution) if it is part of a qualified academic dissertation, but any other internet or mass media use of this material without written permission is STRICTLY prohibited.  Requests for such usage may be forwarded to me using the email button in the right shared border. If permission is granted, you must credit me for the use of the material and link to this website prominently from your own.  Dentists and web developers who cut and paste content and/or images from doctorspiller.com into their own websites and claim them as their own are forewarned that this may result in legal action.  Click here for more information concerning the copyright on this material.

DISCLAIMER: Statements made on this web site are for informational purposes only and are not intended to be substituted for the advice of a medical professional.   Information and statements have not been evaluated by the American Dental Association or any federal regulation agency and are not intended to diagnose, or treat any disease or medical condition.  This is a personal website written by an individual dental professional whose intention is to enlighten the public with generally accepted, mainstream medical/dental information.  I do not claim to represent the opinions of all dental or medical professionals. No website is a substitute for a visit to a living, breathing dentist or physician who can deal with you personally.  

Enter your search terms Submit search form   Web doctorspiller.com