Protein Synthesis

Protein Synthesis requires various parts of the cell. The process is elaborate and must be precise for it to work properly and effectively. Deoxyribonucleic acid, or DNA has a double helix structure composed of three basic components: a five-carbon sugar called deoxyribose, a phosphate group, and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine, guanine, cytosine, and thymine. Hydrogen bonds will only shape or form in the middle of certain base pairs: guanine with cytosine and adenine with thymine. These pairs are called complimentary strands because each and everyone aids the other to build and alternative strand.

RNA is a single-stranded nucleic acid molecule also involved in protein synthesis. Protein synthesis is composed of two main classifications: transcription, which is the process of copying RNA information to DNA, and translation, which is the process of turning RNA information to DNA. There are various types of RNA within a cell, each playing a specific role in the synthesis of protein molecules. The three main types of RNA are messenger RNA, ribosomal RNA, and transfer RNA.

Messenger RNA (mRNA) carries the instructions for assembling amino acids together into large protein molecules to other parts of the cell. Ribosomal RNA (rRNA) are small organelles, composed of two subunits, where proteins are created. Lastly, transfer RNA (tRNA) molecules transfer each and every amino acid the the ribosomes on the authority of the coded instructions given in the mRNA.

Next, transcription is another part of protein synthesis. It is when “a segment of DNA is used to produce a complementary mRNA molecule,” as stated in lesson 3.05, on page 4. Transcription uses a special protein called RNA polymerase, similar to form and purpose as DNA polymerase. Transcription begins when the RNA polymerase attaches itself to a DNA molecule and divides its strands. One of the DNA strands serves as a template to build nucleotides together into a complimentary mRNA strand. Determined base sequences on the DNA molecules (promoters), signal where the enzyme (RNA polymerase) should being transcribing a section of mRNA, and later other base sequences on the DNA then indicate the new mRNA is finished, meaning transcription stops.

After transcription, the new mRNA component leaves the nucleus and enters the cytoplasm. The mRNA is then used in translation, which happens in the cell’s ribosomes. The procedure uses the genetic code on the mRNA strand to guide the fabrication of a protein molecule. First a ribosome joins with a mRNA molecule, and as each codon passes through the ribosome, tRNA molecules bring the parallel amino acid into the ribosome. Each transfer RNA molecule has a group of three unpaired nitrogenous babes called anticodons. Each anticodon sequence is compatible to a specific codon on the mRNA. Lastly the protein chain continues to expand until the ribosome reaches a stop codon on the mRNA