What structure is the site of protein synthesis?
Since this is not my area of expertise, I searched Google under the key words "protein synthesis" to get these possible sources:
http://www.accessexcellence.org/RC/VL/GG/protein_synthesis.html
http://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html
http://en.wikipedia.org/wiki/Protein_biosynthesis
http://www.wisc-online.com/objects/index_tj.asp?objID=AP1302
(Broken Link Removed)
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.
The structure responsible for protein synthesis is called the ribosome. Ribosomes are small, complex structures present in all living cells, including bacteria, archaea, and eukaryotes. They play a crucial role in translating the genetic information encoded in DNA into functional proteins.
To understand how ribosomes function as the site of protein synthesis, here's a step-by-step explanation:
1. Transcription: The first step in protein synthesis is the process of transcription, where a segment of DNA (a gene) is copied into a messenger RNA (mRNA) molecule. This occurs in the nucleus for eukaryotes or the cytoplasm for prokaryotes.
2. mRNA processing (in eukaryotes): In eukaryotic cells, the newly synthesized pre-mRNA undergoes various modifications, including the removal of non-coding regions called introns. The remaining coding regions, called exons, are spliced together to form mature mRNA.
3. mRNA export: Once processed, the mature mRNA molecule is transported out of the nucleus and into the cytoplasm. In prokaryotes, as transcription occurs in the cytoplasm, this step is not necessary.
4. Translation: The ribosomes in the cytoplasm or attached to the endoplasmic reticulum (ER) bind to the mRNA molecule to initiate the process of translation. Ribosomes consist of two subunits, large and small, that come together around the mRNA.
5. Codons and anticodons: The mRNA molecule carries a sequence of nucleotides called codons, which code for specific amino acids. Each codon is recognized by a complementary set of three nucleotides called anticodons on transfer RNA (tRNA) molecules.
6. tRNA binding: The appropriate tRNA molecules carrying the corresponding amino acids bind to the codons on the mRNA, facilitated by the ribosome. This forms a polypeptide chain as the ribosome moves along the mRNA molecule.
7. Peptide bond formation: The ribosome catalyzes the formation of peptide bonds between the amino acids brought in by tRNA molecules, forming a growing polypeptide chain.
8. Termination: The process continues until the ribosome encounters a stop codon on the mRNA. At this point, the ribosome releases the completed polypeptide chain, and the mRNA molecule is released and can be recycled for further translation.
In summary, ribosomes serve as the site of protein synthesis, where mRNA molecules are translated into specific amino acid sequences, ultimately resulting in the formation of functional proteins.