Although dna and rna both carry genetic information, there are quite a few differences between them. Rna is a single stranded molecule containing a ribose sugar. The genetic code is the sequence of bases on one of the strands. Maurice wilkins and rosalind franklin by xray diffraction method gave the double helical nature of the dna. There are three main types of rna, all involved in protein synthesis. An important structural feature of rna that distinguishes it from dna is the presence of a hydroxyl. Rna sometimes forms a secondary double helix structure, but only intermittently.
It is a polymeric molecule essential in various biological roles in coding, decoding, regulation, and expression of genes. Rna molecules perform a variety of roles in the cell but are mainly involved in the process of protein synthesis translation and its regulation. Relative thermodynamic stability of dna, rna, and dna. Dna or rna structure is often represented in a shorthand form. Rna or ribonucleic acid is a polymer of nucleotides which is made up of a ribose sugar, a phosphate, and bases such as adenine, guanine, cytosine, and uracil.
It has a distinctive structure and, unlike dna, there are variations and various types of rna structures. Like dna, all rna molecules have a similar chemical organization, consisting of nucleotides. In fact, you have probably even seen a diagram or picture of a dna molecule. Start studying nucleic acids structure of rna and dna. Dna and protein synthesis life is a three letter word. Intramolecular hydrogen bond interactions are formed between bases of the same single strand. Rna properties, structure, types and functions molecular. The horizontal line indicates the carbon chain of sugar with base attached to c 1. A, b and zdna helix families david w ussery,danish technical university, lyngby, denmark there are three major families of dna helices. Each of the nucleotides in rna is made up of a nitrogenous base, a fivecarbon sugar, and a phosphate group. Near the middle of the horizontal line is c 3 phosphate linkage while at the other end of the line is c 5 phosphate linkage fig. Indeed, there is no one generic structure for dna and rna.
You all are well versed in dna and the function it performs. The helical structure of dna is variable and depends on the sequence as well as the environment. With the discovery of the molecular structure of the dna. Rna could have been the original nucleic acid when life first arose on earth some 3. The nucleotides are connected together to form a long chain with the bases pointing out.
The presence of this functional group causes the helix to adopt the aform geometry rather than the bform most commonly observed in dna. Feb 26, 2019 rna is a single stranded molecule containing a ribose sugar. There is some evidence dna may have occurred first, but most scientists believe rna evolved before dna. Dna, rna, replication, translation, and transcription overview recall the central dogma of biology. Because the nitrogenous bases can interact with each other a binding with t and c binding with g two such chains placed opposite to each other form the ladderlike structure of dna, with paired bases making the rungs of the ladder. The structure of dna was given by james watson and francis crick in 1953, for which he received the nobel prize, basing on the discoveries of. Dna and rna can be represented as simple strings of letters, where each letter corresponds to a particular nucleotide, the monomeric component of the nucleic acid polymers. Rna dna 1 single stranded mainly except when self complementary sequences are there it forms a double stranded structure hair pin structure double stranded except for certain viral dna s which are single stranded 2 ribose is the main sugar the sugar moiety is deoxy ribose 3 pyrimidine components differ. Like dna, each rna nucleotide is also composed of three subunits. Dna and rna are both nucleic acids, which are the polymeric acids isolated from the nucleus of cells.
Also, rna is found in prokaryotes, which are believed to precede eukaryotes. The key concept is that some form of nucleic acid is the genetic material, and these encode the macromolecules that function in the cell. Nearly every cell in a persons body has the same dna. Base pairing might occur between bases along the single strand giving rise to various three dimensional folds. Rna oh opo5 ch2 base oh o 4 c 1 c h h h h 3 c 2 c oh 0h adenine guanine cytosine uracil 8 9. Dna helix structure structure of rna hairpin loop from premrna content is available under attributionnoncommercialshare alike 3. Beyond the primary role of rna in protein synthesis, several varieties of rna exist that are involved in posttranscriptional modification, dna replication, and gene regulation.
Unlike doublestranded dna, rna is a singlestranded molecule in many of its biological roles and consists of much shorter chains of nucleotides. This hypothesis can provide an opportunity to trace logically the process of the emergence of the dna double helix. Thymine only present in dna uracil only present in rna structure of dna. A ribonucleotide in the rna chain contains ribose the pentose sugar, one of. Nucleic acids have a primary, secondary, and tertiary structure analogous to the classification of protein structure. That is, rna does not have the ladderlike structure of the dna in figure 3. The structure of dna is dynamic along its length, being capable of coiling into tight loops and other shapes.
The structure of rna differences between rna and dna. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Dna is one of the two types of nucleic acids present in our bodies. Rna, complex compound of high molecular weight that functions in cellular protein synthesis and replaces dna as a carrier of genetic codes in some viruses. Dec 08, 2017 dna, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Third, rnaissinglestrandedusuallywhilednaisdoublestranded. Full sequence published and researchers determined that within this sequence there was somewhere between 30,000 and 40,000 genes. Page 2 of 9 adenine guanine your sheet of four nucleotides, before and after coloring, should look something like figure 1. Structures of nucleic acids some genomes are rna some viruses have rna genomes. Chapter 2 structures of nucleic acids nucleic acids.
Note the difference in groove width and the relative displacements of the base pairs from the central axis. Learn about the structure, types, and functions of rna. Definition, structure, and discovery 1 deoxyribonucleic aci d or dna i s a mol ecul e t hat cont ai ns t he i nst ruct i ons an organism needs to devel op, l i ve and reproduce. Dna genetic information in genes rna copies of genes proteins functional molecules dna structure one monomer unit deoxyribonucleic acid composed of a base, a sugar deoxyribose, and a phosphate. Rna only has one strand, but like dna, is made up of nucleotides. Rna pairs with dna, g and c always pair together, t in dna always pairs with a in rna, but a in dna pairs with u in rna.
Intramolecular hydrogen bond interactions are formed between bases of the same single. Clearly, the structures of dna and rna are richer and more intricate than was at. All of these features were described by watson and crick. Dna dna deoxyribonucleic acid dna is the genetic material of all living cells and of many viruses. There is a second nucleic acid in all cells called ribonucleic acid, or rna. The sequence of bases in the nucleic acid chain gives the primary structure of dna or rna. Its orientation, width, width between nucleotides, length and number of nucleotides per helical turn is constant. Rna consists of ribose nucleotides and the nitrogenous bases adenine, guanine, cytosine, and uracil. A chromosome, for example, is a single, long dna molecule, which would be several centimetres in length when unravelled.
An rna strand can undergo significant intramolecular base pairing to take on a threedimensional structure. The chemical structure of rna is very similar to that of dna, but differs in three primary ways. This is a comparison of the differences between dna versus rna, including a quick summary and a detailed table of the differenc. Dna structure and function of deoxyribonucleic acid dna. Rna is typically single stranded and is made of ribonucleotides that are linked by phosphodiester bonds. Dna is a long polymer made from repeating units called nucleotides, each of which is usually symbolized by a single letter. Dna stands for deoxyribonucleic acid, while rna is ribonucleic acid.
Rna has a simpler structure and is needed in order for dna to function. The chemical structure of rna is very similar to that of dna, with two differencesa rna contains the sugar ribose while dna contains the slightly different sugar deoxyribose a type of ribose that lacks one oxygen atom, and b rna has the nucleobase uracil while dna contains thymine uracil and thymine have similar basepairing properties. The key difference in rna structure is that the ribose sugar in rna possesses a hydroxyl. Dna, rna, replication, translation, and transcription. When rna pairs with rna, then g pairs with c and a pairs with u. Atenrichment in this hypothesis is main factor of evolution of dna double helix from rna double helix. Introduction pictures of the double helix of deoxyribonucleic acid. A gene is a specific sequence of bases which has the information for a particular protein. Adenine is always opposite thymine, and cytosine is always oppostie guanine. Comparison of the thermodynamic stabilities and solution conformations of dnarna hybrids containing purinerich and pyrimidinerich strands with dna and rna duplexes. Differences between dna and rna online microbiology notes.
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