Protein biosynthesis (synthesis) is the process in which cells build proteins. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription which are then used for translation. Translation is the first stage of Protein biosynthesis (part of the overall process of Gene expression) For the non-biological synthesis of amino acids see Strecker amino acid synthesis Amino acid synthesis is the set of Biochemical processes ( Metabolic Transcription is the synthesis of RNA under the direction of DNA Translation is the first stage of Protein biosynthesis (part of the overall process of Gene expression) Protein biosynthesis, although very similar, differs between prokaryotes and eukaryotes. The prokaryotes (proʊˈkærioʊts singular prokaryote /proʊˈkæriət/ are a group of Organisms that lack a Cell nucleus (= karyon or any other Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex
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Amino acid synthesis
Amino acids are the monomers which are polymerized to produce proteins. For the non-biological synthesis of amino acids see Strecker amino acid synthesis Amino acid synthesis is the set of Biochemical processes ( Metabolic A polymer is a large Molecule ( Macromolecule) composed of repeating Structural units typically connected by Covalent Chemical bonds Amino acid synthesis is the set of biochemical processes (metabolic pathways) which build the amino acids from carbon sources like glucose. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as In Biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Not all amino acids may be synthesised by every organism, for example adult humans have to obtain 8 of the 20 amino acids from their diet.
Transcription
Transcription is the process by which an mRNA template, encoding the sequence of the protein in the form of a trinucleotide code, is transcribed from the genome to provide a template for translation. Transcription is the synthesis of RNA under the direction of DNA Messenger ribonucleic acid ( mRNA) is a molecule of RNA encoding a chemical "blueprint" for a Protein product The genetic code is the set of rules by which information encoded in genetic material ( DNA or RNA sequences is translated into Proteins In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby Transcription copies the template from one strand of the DNA double helix, called the template strand. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Sense, when applied in a Molecular biology context is a general concept used to compare the polarity of Nucleic acid molecules such as DNA or RNA
Transcription can be divided into 3 stages: Initiation, Elongation and Termination, each regulated by a large number of proteins such as transcription factors and coactivators that ensure the correct gene is transcribed in response to appropriate signals. In the field of Molecular biology, a transcription factor (sometimes called a sequence-specific DNA binding factor is a Protein that binds to specific sequences A coactivator is a protein that increases Gene expression by binding to an activator (or Transcription factor) which contains a DNA binding domain
The DNA strand is read in the 3' to 5' direction and the mRNA is transcribed in the 5' to 3' direction by the RNA polymerase. RNA polymerase ( RNAP or RNApol) is an Enzyme that produces RNA.
Translation
The synthesis of proteins is known as translation. Translation is the first stage of Protein biosynthesis (part of the overall process of Gene expression) Translation occurs in the cytoplasm where the ribosomes are located. The cytoplasm is the contents of a cell that is enclosed within the Plasma membrane. Ribosomes ( from ribo nucleic acid and "Greek soma ( meaning body") are complexes of RNA and Protein that Ribosomes are made of a small and large subunit which surrounds the mRNA. In translation, messenger RNA (mRNA) is decoded to produce a specific polypeptide according to the rules specified by the genetic code. Messenger ribonucleic acid ( mRNA) is a molecule of RNA encoding a chemical "blueprint" for a Protein product Peptides (from the Greek πεπτίδια, "small digestibles" are short Polymers formed from the linking in a defined order of α- Amino The genetic code is the set of rules by which information encoded in genetic material ( DNA or RNA sequences is translated into Proteins This uses an mRNA sequence as a template to guide the synthesis of a chain of amino acids that form a protein. In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this Translation is necessarily preceded by transcription. Transcription is the synthesis of RNA under the direction of DNA Translation proceeds in four phases: activation, initiation, elongation and termination (all describing the growth of the amino acid chain, or polypeptide that is the product of translation). Peptides (from the Greek πεπτίδια, "small digestibles" are short Polymers formed from the linking in a defined order of α- Amino
In activation, the correct amino acid (AA) is joined to the correct transfer RNA (tRNA). Transfer RNA (abbreviated tRNA) is a small RNA (usually about 74-95 nucleotides that transfers a specific Amino acid to a growing polypeptide chain at While this is not technically a step in translation, it is required for translation to proceed. The AA is joined by its carboxyl group to the 3' OH of the tRNA by an ester bond. When the tRNA has an amino acid linked to it, it is termed "charged". Initiation involves the small subunit of the ribosome binding to 5' end of mRNA with the help of initiation factors (IF), other proteins that assist the process. Initiation factors are proteins that bind to the small subunit of the Ribosome during the initiation of translation, a part of Protein biosynthesis. Elongation occurs when the next aminoacyl-tRNA (charged tRNA) in line binds to the ribosome along with GTP and an elongation factor. Termination of the polypeptide happens when the A site of the ribosome faces a stop codon (UAA, UAG, or UGA). When this happens, no tRNA can recognize it, but releasing factor can recognize nonsense codons and causes the release of the polypeptide chain. The release factor is a Protein that recognizes the Termination codon or stop Codon in a MRNA sequence on the ribosome The capacity of disabling or inhibiting translation in protein biosynthesis is used by antibiotics such as: anisomycin, cycloheximide, chloramphenicol, tetracycline, streptomycin, erythromycin, puromycin etc. In modern usage an antibiotic is a Chemotherapeutic agent with activity against Microorganisms such as Bacteria, fungi or Protozoa Anisomycin, also known as flagecidin is an Antibiotic produced by Streptomyces griseolus which inhibits protein synthesis. Cycloheximide is an inhibitor of Protein biosynthesis in eukaryotic organisms produced by the bacterium Streptomyces griseus Chloramphenicol is a Bacteriostatic Antimicrobial originally derived from the Bacterium Streptomyces venezuelae, isolated by This article deals with the specific antibiotic called tetracycline Streptomycin is an Antibiotic drug the first of a class of drugs called Aminoglycosides to be discovered and was the first antibiotic remedy for Tuberculosis Erythromycin is a Macrolide Antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of Penicillin, and is often used for people Puromycin is an Antibiotic that is a potent inhibitor of translation.
Events following protein translation
The events following biosynthesis include post-translational modification and protein folding. Posttranslational modification (PTM is the chemical modification of a Protein after its translation. Protein folding is the physical process by which a Polypeptide folds into its characteristic and functional three-dimensional structure. During and after synthesis, polypeptide chains often fold to assume, so called, native secondary and tertiary structures. In Biochemistry and Structural biology, secondary structure is the general three-dimensional form of local segments of Biopolymers such as In Biochemistry and Chemistry, the tertiary structure of a Protein or any other Macromolecule is its three-dimensional structure as defined This is known as protein folding. Protein folding is the physical process by which a Polypeptide folds into its characteristic and functional three-dimensional structure.
Many proteins undergo post-translational modification. This may include the formation of disulfide bridges or attachment of any of a number of biochemical functional groups, such as acetate, phosphate, various lipids and carbohydrates. In Chemistry, a disulfide bond is a single Covalent bond derived from the coupling of Thiol groups In Organic chemistry, functional groups are specific groups of Atoms within Molecules that are responsible for the characteristic Chemical reactions An acetate, or ethanoate, is either a salt or Ester of Acetic acid. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Lipids are broadly defined as any fat- Soluble ( lipophilic) naturally-occurring Molecule, such as fats oils waxes cholesterol sterols fat-soluble Carbohydrates (from ' Hydrates of Carbon ' or saccharides ( Greek σάκχαρον meaning " Sugar " are the most Enzymes may also remove one or more amino acids from the leading (amino) end of the polypeptide chain, leaving a protein consisting of two polypeptide chains connected by disulfide bonds. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins
See also
External links
- Translation of mRNA Section of The Cell: A Molecular Approach by Geoffrey M. The genetic code is the set of rules by which information encoded in genetic material ( DNA or RNA sequences is translated into Proteins History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance An operon is a functioning unit of key Nucleotide sequences including an operator, a common Promoter, and one or more structural Genes, The lac operon is an Operon required for the transport and Metabolism of Lactose in Escherichia coli and some other Cooper
- Science aid:Protein synthesis For high school
- Protein Synthesis
- Transcription
- Protein Synthesis Animation Wesleyan University Learning Objects animation of protein synthesis.
- Interactive Java simulation of transcription initiation. From Center for Models of Life at the Niels Bohr Institute.
- From RNA to Protein Synthesis hypervideo.
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