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DNA –> RNA –> Protein (in greater detail)

I emphasize the importance of ‘the central dogma’Image pretty regularly throughout the semester in General Biology. This idea represents one of the core theories of biology and helps to explain an enormous amount about life. This ‘dogma’ explains how the information contained in DNA is replicated prior to cell division – and used to make drafts of that information (RNA) that can guide the construction of proteins that get the work of the cell done.

In the current unit, we are expanding this theory and examining the processes and the molecules they create more closely. Fortunately, each of these processes is elegantly illustrated in a set of animations available on the HHMI website.

The first video presents a model of replication. The model (as shown) is correct in its idea, but is not intended to be a model of HOW replication occurs, only how, in the words of Watson and Crick, “… [T]he specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.”

http://www.hhmi.org/biointeractive/media/DNAi_replication_schematic-lg.mov

The actual mechanism of DNA replication is complicated by the anti-parallel arrangement of the paired DNA strands and the fact that DNA Polymerase, the enzyme responsible for copying the DNA, can work only in one direction.

The action of the DNA polymerase, along with some additional enzymes (Helicase and Ligase) is illustrated mechanistically in the following animation:

http://www.hhmi.org/biointeractive/media/DNAi_replication_vo2-lg.mov

Screen Shot 2013-04-30 at 6.36.15 PMOnce DNA is replicated, during S Phase of the cell cycle, the cell is ready to divide and provide one complete copy of the DNA to each of the two daughter cells. In this way, DNA replication allows for the continuity of genetic information from one generation (of cells or whole organisms) to the next.

Throughout the cell’s life, it is necessary to produce proteins to accomplish the work of that particular cell. Again, the information contained in the DNA is copied, this time to a messenger RNA (mRNA) strand, and the instructions to make the protein are carried into the cytoplasm. This process, called Transcription, is carried out primarily by the enzyme, RNA polymerase, as illustrated below:

http://www.hhmi.org/biointeractive/media/DNAi_transcription_vo2-lg.mov

Once an mRNA is constructed, it is transported from the nucleus (where the DNA resides) into the cytoplasm. There, a Ribosome will coordinate the recruitment of transfer RNAs (tRNA) bearing specific Amino Acid building blocks called for to synthesize the protein. This process, called translation, is illustrated by HHMI below:

http://www.hhmi.org/biointeractive/media/DNAi_translation_vo2-lg.mov

 
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Posted by on April 29, 2013 in Uncategorized

 

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Wired Article about EteRNA

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Citizen Scientists

I forgot… I meant to post a link to an article written in Wired magazine about the EteRNA RNA folding game. It’s an interesting look into how crowdsourcing is beginning to make inroads into science and how clever gamification turns readers into players and puts them to work on deciphering some of the largest data-heavy / problem-solving questions in science. Find that article here, or you can also find the actual magazine at FSCC in the hallway magazine shelf.

 
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Posted by on November 26, 2012 in Uncategorized

 

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EteRNA

I meant to mention in class that I wanted anyone who is interested to check out EteRNA¬†online¬†over the holiday. We are going to be talking about DNA, RNA and Proteins again in chapter 25 and EteRNA is an interesting game that gives players a look into the world of RNA folding. I will mention this again in class this week, but if anyone wants to check it out, I will award a ’10’ on the chapter 25 quiz to the player with the highest score by that time.

 
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Posted by on November 25, 2012 in Uncategorized

 

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