Introduction:
DNA by means of its correct method of replication serves to carry genetic information from cell to cell and from generation to generation. The information is converted into proteins which find out the phenotype. Protein synthesis comprises how the information presents in the sequences of bases (that is, triplet codons) of the mRNA is converted into a sequence of amino acids in the proteins.
The Central Dogma:
Genes are the instructions for forming specific proteins. However a gene doesn't build a protein directly. The bridge between genetic information and protein synthesis is the RNA. The method of synthesis of protein comprises one of the central dogma of molecular biology; that postulates that genetic information flows from nucleic acids to protein. The primary step of the central dogma is termed as transcription and doesn't comprise a change of code since DNA and mRNA are complementary. The subsequent step comprises a change of code from nucleotide sequences to amino acid sequences and is termed as translation described as follows:
Duplication -> DNA -> (Transcription) -> RNA -> (Translation) -> Protein
Method of Protein Synthesis:
Protein synthesis is a much complex biochemical transformation functioned by cells resultant in the formation of a polypeptide chain. The method of protein synthesis can be splitted into the following three main steps: chain initiation, chain elongation and chain termination. All the three steps need protein factors (around 200 different proteins) generally enzymes which aid in mRNA, tRNA and ribosomes in the translation process. Chain initiation and elongation need energy generally given by GTP (that is, guanosine triphosphate), a molecule which is closely associated to ATP.
1) Chain Initiation:
The initiation phase brings altogether mRNA a tRNA bearing the first amino acid of the polypeptide chain and the two subunits of the ribosome. At first a small ribosomal subunit combines or binds to both mRNA and a special initiator tRNA. The small ribosomal subunit joins to the end of the mRNA (loading site). Downstream from the loading site is the initiation codon, AUG, where translation actually starts. The initiator tRNA that carries the amino acid methionine, joins to the initiation codon. The union of mRNA, imitator tRNA and small ribosomal subunit is followed by the attachment of a big ribosomal subunit to form a functional ribosome. Proteins called imitation factors are needed to bring these components altogether. The cell as well spends energy in the form of one GTP to form the initiator complex. At the completion of the initiation procedure, the initiator tRNA sits in the P site of the ribosome, and the vacant A site is ready for the subsequent tRNA.
2) Chain Elongation:
The elongation phase amino acids are added one by one to the initial amino acid attached by the peptide bond. Each addition comprises the participation of some proteins termed as elongation factors. The entire process takes place in a three-step cycle.
a) Codon Recognition:
The mRNA codon in A site of the ribosome forms hydrogen bonds having the anticodon of an incoming molecule of tRNA carrying its proper amino acid. An elongation factor employs the tRNA into the A site. This step needs the hydrolysis of a phosphate bond from GTP.
b) Peptide Bond Formation:
A component of the big ribosomal subunit catalyzes the formation of a peptide bond among the polypeptide extending from the P site and the newly arrived amino acid in the A site. In this step, the polypeptide separates from the tRNA to which it was bound and is transferred to the amino acid taken out by the tRNA in the A site.
c) Translation:
The tRNA in the P site dissociates from the ribosome. The tRNA in A site, now joined to the growing polypeptide, is translocated to the P site. As the tRNA modifies sites, its anticodon remains hydrogen-bonded to the mRNA codon, let the mRNA and tRNA molecules to move as a unit. This movement brings the subsequent codon to be translated into the A site. The translocation step needs energy that is provided by hydrolysis of a GTP molecule.
3) Chain Termination:
The final phase of translation is the termination. Elongation carries on till a termination codon reaches the A site of the ribosome. Nonsense base triplets - UAA, UAG and UGA - don't code for amino acids however rather act as signals to stop the translation.
A protein termed as a release factor joins directly to the termination codon in the A site. The discharge factor causes the ribosome to add a water molecule rather than an amino acid to the polypeptide chain. This reaction hydrolyses the completed polypeptide from the tRNA that is in the P site, thus freeing the polypeptide from the ribosome. The ribosome then separates to its small and big subunits.
From Polypeptide to Functional Protein:
Throughout and after its synthesis, a polypeptide chain starts to coil and fold spontaneously, making a functional protein of specific conformation: a three-dimensional molecule having secondary and tertiary structures. A gene finds out primary structure and primary structure in turn finds out the conformation.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with a tutor at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online biology tutoring. Chat with us or submit request at [email protected]
asymmetric information theory and key concepts of asymmetric information, adverse selection, Signaling, nondiscriminatory auction, contingent payment and discriminatory auction, answering questions to managerial economics homework help, assignment help.
Hire qualified and experienced tutors from Nuclear Physics Assignment Help and get finest paper to score high!
In an organism, any observable defect in chromosome number / structure from the diploid set is termed as chromosomal aberration.
tutorsglobe.com laboratory diagnosis assignment help-homework help by online herpes viruses tutors
Theory and lecture notes of Non-deterministic Pushdown Automata all along with the key concepts of non-deterministic pushdown automata, Finite Automata with External Storage, Definition NPDA, Example of NPDA. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Non-deterministic Pushdown Automata.
Gravimetric Analysis tutorial all along with the key concepts of Types of Gravimeter analysis, Precipitation Gravimetric Analysis, Volatilization gravimetric analysis, Application of Gravimetry
Online ACT exam preparation and online act tutoring package offered by TutorsGlobe are the most comprehensive and customized collection of study resources on web, offering best collection of act practice papers, quizzes, act test papers, and guidance.
Chemical methods of controlling Microbial growth tutorial all along with the key concepts of Definition of Disinfection, Antimicrobial Agents, Ideal Antimicrobial Agent or Disinfectant, Chemical Antimicrobial Agents, Phenolics, Alcohols, Halogens and Quaternary Ammonium Compounds
application and scope of managerial economics including the key concepts of managerial economics, average value, horizontal boundaries, marginal value, vertical boundaries, imperfect market, economic model, market power and stock
Theory and lecture notes of Recovery Management all along with the key concepts of Model of Errors, Model of Storage Errors, page transfer, Model of Data Communications Errors. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Recovery Management.
Vascular Elements of Seed Plants tutorial all along with the key concepts of characteristics of Vascular plants, Vascular Plant Structure, Nutrient distribution and Absorption
Grab the opportunity to get your paper drafted by qualified tutors of Plant Diversity Assignment Help at affordable prices and score A++
www.tutorsglobe.com offers functional group reactions of alkane, homework help, assignment help, online tutoring assistance, functional group reactions of alkane organic chemistry solutions by online qualified tutors help.
Adaptive Radiation of Chordates tutorial all along with the key concepts of kinds of adaptive radiation, General adaptation, Environmental change and Archipelagoes
TutorsGlobe.com Nucleophilic Reactions Assignment Help-Homework Help by Online Benzene & Derivatives Electrophilic Substitution Tutors
1943750
Questions Asked
3689
Tutors
1468882
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!