Protein Synthesis
DNA – is the molecule that carries the genetic information in all cellular forms of life and some viruses. It belongs to a class of molecules called nucleic acids, which are polynucleotides.
Each nucleotide consists of three components.
• A nitrogenous base: cytosine, guanine, adenine or thymine.
• A deoxyribose sugar
• A phosphate molecule
The back bone of the polynucleotide is a chain of sugar and phosphate molecules. Each sugar molecule in the sugar phosphate backbone is linked to one of the four nitrogenous bases. DNA has the ability to store and transmit information this rests on the fact that it is made up of 2 polynucleotide strands that are coiled together to create a double helix structure. The nitrogenous bases link across the 2 polynucleotide strands by using hydrogen bonds. A-T C-G. Adenine and Thymine can only have 2 hydrogen bonds, whilst Cytosine and Guanine have 3 hydrogen bonds.
MRNA and tRNA exist in chains consisting of building blocks called RNA nucleotides. Each of these nucleotides consist of a sugar called ribose, a high-energy chemical group, called phosphate, and one of the four nitrogenous bases.
Synthesis of mRNA and tRNA
The mRNA and tRNA are synthesised through a process called base pairing and transcription. A chain of mRNA is laid down alongside a strand of DNA. The mRNA synthesis happens in
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A protein that is going to be degraded has copies of the protein ubiquitin attached to it by ubiquitin-adding enzymes. This enzyme tags the protein that is being degraded to notify the cell that it needs to be degraded. The tagged proteins are sucked into a proteasome, this is a protein based component, inside the proteasome, and the protein it has ingested is digested into small peptide fragments, these fragments are then released into the cytoplasm where other proteases digest it even further until it becomes free amino
The study of nucleic acids has now become a fruitful and dynamic scientific enterprise. Nucleic acids are of unique importance in biological systems. Genes are made up of deoxyribonucleic acid or DNA, and each gene is a linear segment, or polymer, of a long DNA molecule. A DNA polymer, or DNA oligonucleotide, contains a linear arrangement of subunits called nucleotides. There are four types of nucleotides. Each nucleotide has three components; a phosphate group, a sugar and a base that contains nitrogen within its structure. The sugar moiety in DNA oligonucleotides is always dexoyribose, and there are four alternative bases: adenine (A), thymine (T), guanine (G), and cytosine (C). The phosphate groups and the deoxyribose sugars form the backbone of each DNA stand. The bases are joined to the deoxyribose sugar and stick out to the side. Both oligomers, DNA and RNA, consist of 5’->3’ phosphodiester-linked nucleotide units that are composed of a 2’-deoxy-D-ribose (DNA) or D-ribose (RNA) in their furanose forms and a heteroaromatic nucleobase (A, T, G, and C; A, U, G, C), and the resulting oligonucleotide chain is composed of a polar, negatively charged sugar-phosphate backbone and an array of hydrophobic nucleobases. The amphiphilic nature of these polymers dictates the assembly and maintenance of secondary and tertiary structures the oligonucleotides can form. In the DNA duplex structure, genetic information is stored as a linear nucleotide code. This code can be accessed and replicated. RNA, or ribonucleic acid, is another structurally related essential biopolymer. RNA differs from DNA in having the sugar ribose in place of the deoxyribos...
After the initiation process is complete, amino acids begin to be added to the polypeptide in a three step process known as elongation. First, the mRNA codon in the A site pairs with the anticodon of an incoming tRNA molecule. Next, the polypeptide separates from the tRNA in the P site and attaches to the amino acid that was carried by the tRNA in the A site. The ribosome catalyzes formation of the bond. Finally, the P site tRNA leaves the ribosome and the ribosome moves the tRNA in the A site to the P site with its attached polypeptide. A new tRNA is then able to bind to the A site to start the elongation process over again. Eventually, a stop codon will reach the A site signaling the amino acid to stop translation
Protein synthesis first begins in a gene. A gene is a section of chromosome compound of deoxyribonucleic acid or DNA. Each DNA strand is composed of phosphate, the five-carbon sugar deoxyribose and nitrogenous bases or nucleotides. There are four types of nitrogenous bases in DNA. They are (A)denine, (G)uanine, (T)hymine, (C)ytosine and they must be paired very specifically. Only Adenine with Thymine (A-T) and Guanine with Cytosine (G-C).
Protein synthesis consists of two main steps: transcription and translation. The DNA is found inside of the nucleus and there in the nucleus a copy of one side of the DNA strand is made, this is the messenger RNA or mRNA. After this the mRNA travels through the cytoplasm with the DNA copy and arrives at the ribosomes. The mRNA then goes through the ribosome three bases at a time. A transfer RNA molecule or tRNA then bring the correct amino acid to match the codon. The amino acids then link together to form a long chain of proteins, making amino acids the building blocks of
1. DNA is a nucleic acid that carries the genetic information in the cell and is capable of self-replication and synthesis of RNA. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. The sequence of nucleotides determines individual hereditary characteristics.
There is a two step process involved in order for the genes to be used. The first half of this process is called transcription. DNA is made up of four nucleotides: adenine, cytosine, guanine, and thiamin. These nucleotides are in pairs in the DNA and their order is very important because it dictates how the gene will be expressed. During transcription RNA, a similar molecule to DNA, comes in and makes the compliment copy of the DNA sequence. The second half of this process is called translation. During translation the RNA is used to make amino acids, which are then used to make a protein. Not all of the RNA is used to make the amino acids, only the sections which are between the start and stop signals. Then sets of three nucleotides called codons are used to make specific amino acids. Different sets of amino acids code for different proteins.
Gene expression can be described as the conversion of information from genes into messenger RNA by way of transcription. Transcription happens in the nucleus, and is where RNA copies of DNA are produced. This process is facilitated by RNA polymerase, where one RNA nucleotide is added to an RNA strand. RNA polymerase is an enzyme used to produce transcripted RNA. It is responsible for constructing RNA chains, in the process previously described as transcription. RNA polymerase polymerizes the ribonucleotides and the 3’ end of RNA transcription. It is essential to life and found in all organisms. Also, it unwinds the DNA molecule, using it as a template, before synthesizing corresponding mRNA strands. mRNA, or messenger RNA, is part of a large group of RNA molecules that communicate information from DNA to ribosomes. mRNA contains adenine, uracil, guanine, and cytosine. Alternative to DNA which has thymine instead of uracil.
Each of the nucleotides accommodate a phosphate group, sugar group, and a nitrogen base. There is four nitrogen bases in DNA. The four nitrogen bases are; Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). Each of the bases are connected to a sugar molecule and a phosphate molecule. They are then positioned into two long strands that form a spiral called a double helix (DNA). The nitrogen bases are paired up with one another. Adenine and Thymine will always be paired with each other because of the bonds between them. Between A and T, there are two hydrogen bonds. The same goes with Guanine always being paired with Cytosine due. Between both G and C there is three hydrogen bonds. The nitrogen bases Adenine and Guanine won’t pair up with each other because, of their size. Both the nitrogen bases Adenine and Guanine are a purine base. Thymine and Cytosine are both a pyrimidine base. Adenine pairs with Thymine, and Guanine pairs with Cytosine, because they are of opposite
Ribonucleic acid or RNA is a polymeric molecule made up of one or more nucleotides. A polymeric molecule is a very large molecule that is chain- like. It is made up of monomers, which are smaller molecules. A strand of RNA can be thought of as a chain with a nucleotide at each chain link. Whereas, a nucleotide is a group of any type of molecules that are linked together because they form the “building blocks” of DNA (also known as deoxyribonucleic acid, and it is the carrier of genetic information.) Messenger RNA, which is called mRNA, carries the genetic information copied from DNA. Transfer RNA, which is called tRNA is the key to deciphering the code words in mRNA that forms a series of three-base code words. An enzyme is a substance that
So now we have an RNA strand. From this strand the protein will be synthesized, this is called translation (RNA is translated into protein). A protein is made from amino acids; these form a strand. I show the protein strand as a linear line, but in reality complex interactions between amino acids lead to 3 dimensional forms that are essential for the functioning of the protein. The translation of RNA to protein is different than the synthesis of RNA from DNA (transcription). When the DNA was transcribed into RNA, one base of DNA corresponded to one base of RNA, this 1 to 1 relation is not used in the translation to protein. During this translation, 1 amino acid is added to the protein strand for every 3 bases in the RNA. So a RNA sequence of 48 bases codes for a protein strand
A DNA molecule is found in the nucleus and is made up of a chain of nucleotides. A nucleotide is a nitrogenous base bonded to a pentose sugar, which is then bonded to a phosphate group (Campbell and Reece, 2013). DNA is also double stranded, which means that each whole DNA molecule has two single chains of nucleotides that act together. T...
Translation is also a process that contains the RNA copy of DNA to make a protein. i.e the mRNA sequence is translated into a sequence of amino acids as a result protein is formed. During translation, RNA molecule is responsible
DNA (deoxyribonucleic acid) is a self-replicating molecule or material present in nearly all living organisms as the main constituent in chromosomes. It encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Simply put, DNA contains the instructions needed for an organism to develop, survive and reproduce. The discovery and use of DNA has seen many changes and made great progress over many years. James Watson was a pioneer molecular biologist who is credited, along with Francis Crick and Maurice Wilkins, with discovering the double helix structure of the DNA molecule. The three won the Nobel Prize in Medicine in 1962 for their work (Bagley, 2013). Scientist use the term “double helix” to describe DNA’s winding, two-stranded chemical structure. This shape looks much like a twisted ladder and gives the DNA the power to pass along biological instructions with great precision.
...cture. Regions 3 and 4 are also complementary and can form this same structure. Which of the two structures form is dependent on the level of trp in the environment. If trp is abundant, then as the ribosome translates over region 1, charged tRNA-trp will arrive at the codon site allowing for fast translation and quick arrival and partial overlap of region 2 making it unavailable to associate with region 3. Region 3 then associates with region 4 signaling for termination and for RNA polymerase to disassociate from the DNA before it transcribes the structural genes. When the environment is starved of tryptophan, as the ribosome translates over region 1, the ribosome stalls as it waits for charged tRNA-trp. This delay allows for the association of region 2 with region 3 preventing the pairing of regions 3 and 4 and permitting the transcription of the structural genes.