Protein+Synthesis



= What is Protein Synthesis? =

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Protein Synthesis can be defined as the transcription and translation of specific parts of DNA to form proteins. The process can be split into two phases. Transcription occurs first, followed by translation. ======

Transcription
Transcription starts with an enzyme called polymerase copying the DNA sequence to a similar molecule called messenger RNA (mRNA). It replaces T with U (Uracil), a helper base, making it clear that the mRNA is a copy. The bases (A, T, G, C) on one strand of the DNA specify the order of bases on the new strand of mRNA (A, U, G, C). The DNA stays inside the nucleus, but the mRNA travels out into the cytoplasm.

Click here for a step through of the process! []

Necesities:

 * 1) DNA
 * 2) Free RNA nucleotides
 * 3) Enzyme Polymerase

Steps:

 * 1) RNA Polymerase attacthes itself to a promoter reigon of DNA, which is typically referred to as the TATA box.
 * 2) RNA Polymerase opens the DNA helix. It makes a little bubble and on strand acts as a template.
 * 3) RNA Polymerase moves down the DNA molecule attaching complementary RNA nucleotides as it goes. This is the same as DNA replication except the DNA "A" pairs with RNA "U"

FOR EXAMPLE:
Template Strand : CCC AGA GGG TTA CTC ATT mRNA Strand: GGG UCU CCC UUA GAG UAA Notice that everything stays the same except the switch from Thymine to Uracil

4. Transcription stops when RNA polyamerase reaches the terminator region of the DNA.

KEY TERMS:
 * Promoter: Start
 * Terminator: End



Watch this helpful Video to further understand the process:

Translation:
Translation is the part of protein synthesis where the ribosomes in the cytoplasm use transfer RNA (tRNA) to attach to the mRNA and translate the bases into amino acids. tRNA molecules bring the specified amino acids that the ribosome links together to make a protein.

Steps:

 * 1) In the cytoplasm, the ribosome binds ot the mRNA, at the start codon. The tRNA molecule with the anticodon UAC also binds to this complex
 * 2) Another tRNA molecule attaches to the ribosome next to the first tRNA. This tRNA molecule will pair with the codon of mRNA following the AUG codon.
 * 3) The ribosome will form a peptide bond between the two ajacent amino acids
 * 4) The ribosome will move down the mRNA. When it moves, the tRNAs will each move down a site. The UAC tRNA is now in the last site - where it will exit the ribosome. Further, the first site is now empty, allowing a new tRNA to attach.
 * 5) This process continues until the ribosome reacehes a stop codon. No tRNA bonds to the ribosome and translation is over.
 * 6) rRNA breaks apart into the 2 subunits again. The mRNA is breaks apart and so the nucleotides can be recycled. The tRNA returns to the cytoplasm to reconnect to amino acids for the future.
 * 7) The new protein is released. The string of amino acids fold up inot the shape of protein.

Helpful link: []



Click Here to watch the process live! []

=﻿OVERVIEW OF ENTIRE PROTEIN SYNTHESIS PROCESS:= INFORMATION LINK: [] ANIMATION LINK: []

Works cited
 * Notes from class
 * All the links
 * []