They are linked together by a peptide bond see later. The wellknown structure of the dna double helix allows this information to be. Function of nucleic acids the purpose of dna is to act as a code or recipe for making proteins. They are major components of all cells 15% of the cells dry weight. The backbone of a nucleic acid molecule is formed by the repeating sequence of pentose and phosphate groups, and this is the same in all molecules. Nucleic acids, deoxyribonucleic acid dna and ribonucleic acid rna, carry genetic information which is read in cells to make the rna and proteins by which living things function. If all the dna in a typical mammalian cell were stretched out end to end, it would extend more than 2 m. Dispersioncorrected dft study of dinucleoside monophosphate single and double.
Clearly, the structures of dna and rna are richer and more intricate than was at. These large molecules are called nucleic acids because they were first identified inside the nucleus of cells, however, they are also found in mitochondria and chloroplasts as well as bacteria and viruses. Structure and function of biomolecules 16 amino acids amino acids are bifunctional compounds containing both a carboxylic acid group cooh and a basic amino group nh2 attached to the same carbon atom fig. The chemical structures for each of the five bases are shown. Secondary structure the primary sequence or main chain of the protein must organize itself to form a compact structure. Structural biochemistrynucleic acid wikibooks, open. What distinguishes one dna or rna molecule from another is the specific sequence of purine and pyrimidine bases present in the chain of nucleotides and the total number of nucleotides i. It has many functions in cells, notably acting as the intermediate between dna and proteins. There are two kinds of nucleic acids, deoxyribonucleic acid dna and ribonucleic acid rna.
The last portion of nucleic acids is the phosphate group. The nucleotides on one strand base pairs with the nucleotide on the other strand. This article covers the chemistry of nucleic acids, describing the structures and properties that allow them to serve as the transmitters of genetic information. Pdf an overview of nucleic acid chemistry, structure, and function. Nucleic acids were first isolated from the cellular nucleus, hence the name. Nucleotides perform a wide variety of functions in the living cells, besides being the building blocks or monomeric units in the nucleic acid dna and rna structure. Nucleotides are composed of a nitrogenous base, a pentose sugar and a phosphate.
Nucleic acids are polymers that consist of nucleotide. The fourth base in rna, however, is not thymine but instead the pyrimidine derived base, uracil u. Nucleic acids are long chainlike molecules composed of a series of nearly identical building blocks called nucleotides. Because a nucleic acid is a polymer of many nucleotide molecules, dna and rna molecules are called polynucleotides. The guanine and thymine content of nucleic acids isolated from normal tissues and animal tumours. Links to pubmed are also available for selected references. Secondary structure is the set of interactions between bases, i. In dna double helix, the two strands of dna are held together by hydrogen bonds.
Based on side chain structure, amino acids can be divided into four groups. You will learn about the different composition and roles of nucleic acids in the cell, their interactions with each other and the use of ribozymes, aptamers, antisense and hybridization as tools in molecular research. Classification of proteins free online biologylife. The rapid developments in the area of genetic engineering and recombinant dna.
Both are composed of unbranched chains of units called nucleotides, each of which contains. This is done in an elegant fashion by forming secondary structure elements the two most common secondary structure elements are alpha helices and beta sheets, formed by repeating amino acids with the same. Nucleic acids are made up of nucleotides, which are substances that themselves consist of three distinct chemical groups. Intro to gene expression central dogma the genetic code. Dna stores genetic information used for the synthesis of proteins including enzymes and is found in the nucleus and mitochondria. Nucleic acids with video tutorials and quizzes, using our many waystm approach from multiple teachers. An extreme example is the case of singlestranded nucleic acids ssnas, which exist in a broad range of unfolded and highly flexible conformations 58. Manual editing of the deduced sequence can be done based on the raw data, but. In rna, the pentose is ribose, whereas in dna it is 2deoxyribose. If the sugar is a compound ribose, the polymer is rna ribonucleic acid.
These molecules are composed of long strands of nucleotides. Describe the primary structure of dna and rna and secondary and tertiary. Nucleic acids can be denatured by the same conditions that denature proteins. The backbone of a nucleic acid is made of alternating sugar and phosphate molecules bonded together in a long chain, represented below. Structure and function of macromolecules 4 the unique properties of the different amino acid r groups will affect the structure of the protein formed so that the number, kind, and bonding sequence of amino acids in a protein is critical. Indeed, there is no one generic structure for dna and rna. Chapter 2 structures of nucleic acids nucleic acids.
He wanted to determine the chemical composition of leucocytes white blood cells, his source of leucocytes was pus from. This group is of immense importance, as it is through this group that dna and rna are held together. If we plot the optical density of dna as a function of temperature, we observe that the increase. The nucleic acids, dna and rna, may be thought of as the information molecules of the cell. Dna and rna are both nucleic acids, which are the polymeric acids isolated from the nucleus of cells. The nucleic acids are vital biopolymers found in all living things, where they function to encode, transfer, and express genes. Dna molecules are the largest of the naturally occurring organic molecules. Side chains with basic groups arginine, lysine, and histidine are called basic amino acids because their side chains are proton acceptors figure 2.
In most cases, they function as effectors for allosteric. Although the information they carry is onedimensional, it is essential to understand the 3d structure of nucleic acids. Structures of nucleic acids some genomes are rna some viruses have rna genomes. Erwin chargaff was a pioneer that tried to construct the composition of dna. Dna the chemical basis of heredity carries the genetic information found in chromosomes, mitochondria and chloroplasts dna is organized into genes fundamental units of genetic information. Basephosphate hydrogen bonds in the bulgedg motif region are annotated following. Proteins determine how an organisms body is built and how it functions, which is why dna is often. Nucleic acids and chromatin openlearn open university. There are two types of nucleic acids, deoxyribonucleic acid, dna, and ribonucleic acid, rna. The structure of dna more than ever become a universal interest in scientic world. Nucleic acids are the biopolymers, or small biomolecules, essential to all known forms of life. Thus, this database is a valueadded one that provides services that are specific to the nucleic. Nucleic acids a polymer formed by linking nucleotides together. The guanidino group in arginines side chain is a relatively strong.
Their main function is to maintain and transmit the genetic code. They are composed of nucleotides, which are the monomers made of three components. This information is stored in the form of long polymer chains. Objectives by the end of lecture the student should. Nucleic acid structure an overview sciencedirect topics. Visualizing singlestranded nucleic acids in solution. Each nucleotide in a chain is made up of three components. Rna molecule and nucleotides within a double structures. Structural properties of nucleic acid building blocks function of dna and rna dna and rna are chainlike macromolecules that function in the storage and transfer of genetic information.
Deoxyribonucleic acid dna the nucleic acid that stores genetic information. Clearly, the structures of dna and rna are richer and more intricate than was at first. The structure of nucleic acids as polymers with unique sequences of bases by way of their nucleotide residues gives way to a high fidelity means of transmitting genetic information by reading and replicating the base sequence for a strand of dna. He found that the amount of adenine a always equaled the amount of thymine t, and the amount of guanine g always equaled the amount of cytosine c. Start studying structure and function of nucleic acids.
Download fulltext pdf download fulltext pdf bdna structure and stability as function of nucleic acid composition. Proteins and nucleic acids structure and function perutz, m. Read this article to learn about composition and structure of the nucleic acids. The components and structures of common nucleotides are compared. Nucleic acid formation from nucleotides the assembly of nucleotides into polynucleotides, or nucleic acids, can be thought of as a dehydration reaction between the 3oh of one nucleotide and the phosphate group of a second nucleotide to form a phosphodiester bond. Nucleic acids are formed by the combination of nucleotide molecules through sugarphosphate bonds known as phosphodiester linkages. It contains annotations that are specific to the structure of nucleic acid and function and tools that allow users to search, download, analyze, and to learn more about nucleic acids apart from the contents available in pdb berman et al. Nucleotides are composed of a nitrogenous base, a fivecarbon sugar, and a phosphate group. Depending on the amount of heat added, a double helix may unwind or even. We explain structure and function of macromolecules. The two main classes of nucleic acids are deoxyribonucleic acid and ribonucleic acid.
In the cell, ssnas are found in a variety of locations, such as in telomeric overhangs at the end of chromosomes, at double stranded dna breaks and at replication forks 9, 10. The structure and function of nucleic acids biochemical society. The structure of a polynucleotide is shown diagrammatically above. Describe the structure and function of proteins and. Structures of nucleic acids chapter 2 structures of nucleic acids dna and rna are both nucleic acids, which are the polymeric acids isolated from the nucleus of cells.
The pentose sugar in rna is ribose, while that in dna is deoxyribose. Nucleic acids are macromolecules, huge polymers with molecular masses of over 100 million. This lesson presents how the structure and function of nucleic acids pertain to living things. The secondary structure is responsible for the shape that the nucleic acid assumes.
Dna is a permanent storage place for genetic information. Nucleosides in the hierarchy of nucleic acid structure, there are two more levels of nomenclature. Nucleic acids are macromolecules that store genetic information and enable protein production. Pdf bdna structure and stability as function of nucleic. The term nucleic acid is the overall name for dna and rna. A study of the structure and function of nucleic acids is needed to be able to understand how information controlling the characteristics of an organism is stored in the form of genes in a cell and how these genes are transmitted to future generations of offspring. Dna is metabolically and chemically more stable than rna. As we shall see in this chapter, there are in fact variations on common themes of structure that arise from the unique physi. Structure and function of nucleic acids flashcards quizlet. Nucleic acids are essential to life, and this quizworksheet will help you check your understanding of many of the key terms and concepts relating to them. Dna replication and rna transcription and translation.
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. Polysaccharides are composed of mono saccharides and proteins are composed of amino acids, nucleic acids are composed of long chains of repeating units called nucleotides. In this section, we will examine the structures of dna and rna, and how these structures are related to the functions these molecules perform. The key concept is that some form of nucleic acid is the genetic material, and these encode the macromolecules that function in the cell. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
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