Cheat Sheets: Transcription and translation

19 Oct

 Genes are instructions for building proteins.

Some proteins are like bricks and mortar, used to build wild, slim features in nerve cells, for example, or to endow muscle cells with tight-knit, fibrous strength.

Some genes code for the proteins that make cells work.  These proteins are like machines, and thousands of different kinds of machines operate in any given cell.  So, if we pile it all up, people are made of trillions of cells and bazillions of proteins that were made off the same genomic recipe book.

Before they build proteins, machines inside of cells must find out how to build them by reading the DNA code of a gene and copying out its instructions.   This process is called transcription. Little factories inside of the cell called ribosomes then read and “translate” the code, making amino acids and linking them together into proteins.

It’s just like any other manufacturing business and process.  First, the business has to have the detailed specs (the genetic code) of what it is going to build (the proteins).  Second, copies of those specs (messenger RNA, or mRNA) get sent out to to all the places within the business that can make it.  Third, someone (like the ribosome) has to read the specs (mRNA) and pull the raw materials together (amino acids) in just the right way and with just the right glue (chemical bonds) to build it.  Finally, the finished product travels out to other businesses to be used (like muscle cells need lots of glucose-6-phosphate dehydrogenase, or G6PD, to break down sugar into raw engergy to power our legs.)

Above, a clip from the PBS production “DNA: The Secret of Life,” credited on Youtube: A Windfall Films Production for Thirteen/WNET New York in association with Channel Four. © 2003 Educational Broadcasting Corporation.

Click here to see all “Cheat Sheet” index cards covering the basics of genetics.


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