Biology: Genetics: 11: DNA and RNA - Transcription - Medical Animation
This animation may only be used in support of a single legal proceeding and for no other purpose. Read our License Agreement for details. To license this image for other purposes, click here.
Biology: Genetics: 11: DNA and RNA - Transcription - Medical Animation
MEDICAL ANIMATION TRANSCRIPT: Now, that we've covered DNA replication, let's talk about Transcription. The first thing you need to know is that transcription has nothing to do with cell replication processes, such as DNA replication, mitosis, or cell division. So what is transcription and why is it necessary? Well, transcription is the first step in the process of using the genetic code in DNA to synthesize or build all the different proteins in your body. One problem with synthesizing these proteins is that the instructions for making them are in the DNA, which is located inside the nucleus. But the place proteins are always made is outside the nucleus, either in the ribosomes floating in the cytoplasm, or in the ribosomes embedded in the rough endoplasmic reticulum. So, how does the genetic code for synthesizing proteins get from the DNA to the ribosome? DNA uses a messenger called messenger RNA or mRNA to carry the genetic code from the nucleus to the ribosome. The process of building this messenger RNA is called Transcription. Now, let's see how transcription happens. Transcription begins when an enzyme called RNA polymerase attaches to a segment of DNA called a gene. A gene contains the code to build a specific protein, which is a macromolecule made up of a sequence of amino acids in a specific order. And within a gene, the specific order of nitrogenous bases dictates the order of amino acids that will make up the protein. Each group of three consecutive bases in the gene is actually a code for a particular amino acid. As a result, each group is referred to as a codon. RNA polymerase causes a particular area of the DNA helix to unwind and separate into two strands. One of the strands, often called the template strand, is the side of DNA that is read or transcribed by the messenger RNA. The other strand of DNA, often called the non-template strand, isn't transcribed by the messenger RNA. So how are DNA instructions transcribed into messenger RNA? Well, using the template strand as a guide, RNA polymerase uses the base pair rule to assemble free nucleotides in the nucleus into a complementary strand of RNA. For example, RNA polymerase reads the DNA base thymine on the template strand then binds it to a free nucleotide containing adenine. This process continues with cytosine binding to guanine and guanine binding with cytosine. Remember though, RNA will never contain thymine. So, whenever RNA polymerase sees adenine on the DNA template strand, it pairs adenine with uracil. By using the template strand of DNA as a guide, the genetic code from the non-template strand of DNA has actually been transcribed into messenger RNA. When transcription is complete, the messenger RNA, which is small enough to fit through a nuclear pore, takes the genetic code out of the nucleus to the ribosome, the site of protein synthesis. The process of actually building the protein at the ribosome is called Translation, which we'll cover in a separate video. To summarize, transcription is the process of transcribing or copying the genetic code for building a protein into messenger RNA. A gene is a segment of DNA containing the instructions or code for building a protein. A codon is a group of three consecutive nitrogenous bases in a gene containing the code for a specific amino acid in a protein. RNA polymerase unwinds the strands of DNA in a gene. The template DNA strand contains the complementary bases that need to be read to generate messenger RNA. The base pair rule is followed when assembling messenger RNA. Messenger RNA is actually a copy of the DNA non-template strand with uracil substituted for thymine.
"Thank you very much for the great work on the medical exhibits. Our trial
resulted in a $16 million verdict for a 9 year old boy with catastrophic
injuries, and the medical illustrations definitely played key role in the
trial."
David Cutt
Brayton Purcell
Salt Lake City, UT
"At 3 PM it hit me--I needed exhibits of a tracheostomy, a coronary artery
bypass and a deep vein thrombosis--all in time for a for-trial video
deposition the next day. The Doe Report had each exhibit on line. In
addition, I ran across an exhibit I hadn't even thought of: reduced ejection
fraction after a heart attack. Because this was a video deposition, I could
use the e-mail version of the medical exhibit, print it on my color copier,
and let the camera zoom in. For $400, less than one blow-up by one of The
Doe Report's competitors, I got four first-rate exhibits in less than a day.
The Doe Report saved me time and money."
"Medical illustrations are essential during trial for any medical malpractice case. The people at MLA have the uncanny ability of creating medical illustrations that simplify the most complex of medical concepts and human anatomy to a lay audience. The exhibits of MLA allow experts to easily describe complex concepts and human anatomy in a manner that could
not be done otherwise.
In addition, their custom illustrations show in great detail the extent of
injuries suffered and the devastating effects they have had on the client's
anatomy. These custom illustration can show, side by side, the body before
and after a catastrophic injury. The effect of this juxtaposition is
unmatched by any testimony that can be adduced at the time of trial.
Even jurors after trial have commented on the ease with which they grasp
medical concepts and anatomy once the MLA exhibits were introduced and
used by my experts. Even judges who have "seen it all" are thoroughly
impressed by the detail and sophistication of the illustrations.
"The illustrations have consistently been well documented, accurate and
timely. Most important though is that the illustrations demonstrate to
juries and claims people the persuasive power of visual communication. Our
firm has achieved multiple eight figure settlements and verdicts over the
past ten years... Medical Legal Art has been there with us on every case."
Thomas C. Jones
Davis, Bethune & Jones, L.L.C.
Kansas City, MO www.dbjlaw.net
Medical Legal Art creates medical demonstrative evidence (medical
illustrations, drawings, pictures, graphics, charts, medical animations,
anatomical models, and interactive presentations) for use during legal
proceedings, including research, demand letters, client conferences,
depositions, arbitrations, mediations, settlement conferences, mock jury
trials and for use in the courtroom. We do not provide legal or medical
advice. If you have legal questions, you should find a lawyer with whom you
can discuss your case issues. If you have medical questions, you should seek the advice of a healthcare provider.