(d)++Making+Proteins+(Q+14-19)



For the synthesis of proteins, each gene carries a series of coded instructions, otherwise known as “code words”. Each “code word” on the DNA is made up of three bases, or “three letters”, that are in a certain order. Each of these “code words” is called a **triplet **, and it corresponds to a single amino acid in a protein. This coded information in the genes is located in the chromosome, which are in the nucleus. Each triplet codes for the building up of a specific amino acid into protein. This protein gives the cell or organism a particular characteristic.



__Summary of the process of making protein:__

The message on the DNA is copied onto another base sequence in the RNA, using very similar base pairing rules to those used in the replication of DNA (mRNA). mRNA then leaves the nucleus and goes to a ribosome. Inside the ribosome the message on the mRNA is read and an amino acid is built.

__Details on the Process of Making Proteins:__

 DNA cannot leave the nucleus because the nuclear pores only allow things of a certain size to exit the nucleus, but since even the smallest molecule of chromosomal DNA is way too big for the pore, the DNA cannot leave the nucleus. The nuclear envelope also keeps the DNA inside the nucleus. Therefore the transcription stage is required as the sequence of triplets required to create the protein is transcripted into a mRNA. A RNA is a single strand of genetic information that only contains partical information copied from the DNA, so it is small and get through the pores. RNAs have 4 bases just like DNAs but the base; thymine is replaced by Uracil in a RNA. When the RNA copies information, Uracil pairs with Adenine instead of Thymine.

After the mRNA copies the information and exits the nucleus, it goes to the ribosomes where the translation stage occurs. The mRNA enters the ribosome with 3 nucleotides at a time (triplet/codon) then a t-RNA with the corresponding triplet comes. For example: If the mRNA has the triplet AUG then the tRNA with UAC will come. Each tRNA has a specific amino on it, and when those amino acids join to make a proteind.

Gene Expression: Making protein occurs in two different process:
 * Transcription: DNA → RNA
 * Translation: RNA → Protein

It only takes 10 seconds for a ribosome to build up a molecule of haemoglobin that contains over 600 amino acids as this process is extremely rapid.

DNA transcription and translation: Click here for a [|helpful animation!]

Youtube Video for further aid: media type="youtube" key="983lhh20rGY" height="315" width="420"

Works Cited: Pickering, W. R.. //Complete biology //. Oxford: Oxford University Press, 2000. Print. //The Genetic Code//. N.p., n.d. Web. 24 May 2012. . “Triplet.” //Super Glossary//. N.p., n.d. Web. 24 May 2012. []. "Gene Expression: Transcription." Transcription<span style="background-color: #ffffff; font-family: 'Times New Roman',Times,serif; font-size: 16px;">. N.p., n.d. Web. 01 June 2012. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Transcription.html>. Complete Biology. Chapter 11-03. How the code is carried. 29 May 2012. DNA Transcription and Protein Assembly. 2008. YouTube. Web. 30 May 2012.<http://www.youtube.com/watch?v=983lhh20rGY>.