Expert: John Locke - 5/28/2007

Question
what are genes?Descibe process of transcription & translation.

Answer
Thanks for using AllExperts, Ahmad.

I need to take a step back to answer your question, starting with how most essential processes take place in cells. Proteins are responsible for most of the work that occurs in cells; they speed up chemical reactions that would otherwise happen much too slowly for life to exist. The manufacture of proteins is one of the most important capabilities of cells; this manufacture is ultimately controlled by DNA. Each cell contains all the instructions needed to manufacture any proteins that it might need--this information is stored in the form of DNA. I also have to mention the organization of DNA so as to define the term "gene."

I'm going to discuss eukaryotic cells, which means that they are compartmentalized: the cell handles different functions in specific, distinct areas. Cells that do not do this--called prokaryotic cells--are evolutionarily more primitive; although they do not have unique areas for different functions, the processes of transcription and translation are basically the same. More on the features of prokaryotic organisms can be found here:

http://library.thinkquest.org/C004535/prokaryotic_cells.html   

Back to eukaryotic cells. They store their DNA in a nucleus, in the form of chromosomes; each chromosome is a single, very long piece of DNA. Not all of the DNA on one chromosome serves the same function--in fact, thousands of separate instructions for making proteins can be found on any one chromosome. Each of these separate regions is termed a gene--a continuous region of DNA with a single set of instructions for the cell. An alternative definition that gets across the same information can be found here:

http://www.accessexcellence.org/RC/VL/GG/genes.html

Speaking very generally, when a cell wants to make a protein, it reads a specific gene and makes a copy of it. This is the process of transcription. This piece is sent to another part of the cell where it's used to make the protein that the transcribed DNA is responsible for; this is the process of translation. Now, the details of each are quite complex, and if I tried to describe them here only in text, the result might be a bit confusing. As such, I've found a nice animation that describes transcription:

http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a2.html

And one that describes translation, along with transcription:

http://www.scienceaid.co.uk/biology/genetics2/proteinsynthesis.html

The second link may contain terminology that you are not familiar with; these terms are defined elsewhere on the site (you may wish to start with this link and continue from there: http://www.scienceaid.co.uk/biology/genetics2/)
If you are still unclear, feel free to contact me again for clarification.