The length of dna varies from species to species, and is usually expressed in terms of base pair composition and contour length. A single strand of a dna molecule consists of a chain of nucleotide subunits colored boxes. Dna stands for deoxyribonucleic acid, while rna is ribonucleic acid. Nov 01, 2012 describe the biochemical composition, structure, and replication of dna. Chapter 8 the chemical reactions of dna damage and degradation. Dna chemical composition a single strand of a dna molecule consists of a chain of nucleotide subunits colored boxes. Dna is made up of pentose sugars, a nitrogenous base and a phosphate group. Also, each step has an associated thumbtack, that if the mouse pointer is placed over it, a dialog box appears detailing that particular step. Most people are familiar with the doublehelical model of a doublestranded dna. The most important feature of dna is that it is usually composed of two polynucleotide chainstwisted around each other in the form of a double helix figure 61.
In dehydrated environments, the dna may appear as adna. The remarkable properties of the nucleic acids, which qualify these substances to serve as the carriers of genetic information, have claimed the attention of many investigators. The deoxyribonucleic acid dna of most organisms contains the purine bases adenine a and guanine g and the pyrimidine bases thymine t and cytosine c. This is due to the negatively charged phosphates in the sugarphosphate backbone. Yielding a series of dna fragments whose sizes can be. Except for some viruses, lifes genetic code is written in the dna molecule aka deoxyribonucleic acid. This animation explores the chemical components and bonds of the nucleotides. Base composition consider wordcount emboss suite which gives one the option of choosing the word size, and gems genomatix, germany. Quizlet flashcards, activities and games help you improve your grades. Therefore, dna is a very important component of life in general and plays a vital role. In 1992, brenner and lerner hypothesized that individual chemical transformations could be encoded in dna, allowing the rapid synthesis and screening of large collections of small molecules. The articles are accessible for immediate viewing through pdf files, so the viewer does not have to hunt around third party websites for this information.
Next, two new strands are made by reading each side of the dna ladder, one step base at a time. Discuss how recombinant dna techniques may be used to correct a point mutation. From the perspective of design, there is no human language that can match the simplicity and elegance of dna. Each nucleotide is made of the sugar deoxyribose connected to an inorganic phosphate group, and to one of four nitrogenous bases. There are two types of nucleic acids, deoxyribonucleic acid, dna, and ribonucleic acid, rna. Mar 24, 2015 their creation is a continuous process, and a single protein chain can have 1015 amino acids added to it per second via the process outline above. This finding of the helical structure of the dna also ties together the results of several diverse studies. Describe the biochemical composition, structure, and replication of dna. Learn vocabulary, terms, and more with flashcards, games, and other study tools. But from the perspective of implementationhow it is actually written and.
The other two bases, cytosine and thymine, have a singlering structure of a type called a pyrimidine. The specific matching of the base pairs, a with t and c with g, provides a way for exact copies of dna to be made. Nucleic acids dna rna are long chains of repeated nucleotides a nucleotide consists of. Usually chromatin is composed of dna, protein and rna. The chemical synthesis of oligonucleotides by andrei laikhter and klaus d. Steve hahnhahn lab last modified 1600 the method below works well for sequencing of dna of greater than. The groundwork was laid by pioneer biochemists who found that nucleic acids are long chainlike molecules, the backbones of which consist of repeated sequences of. Thus, dna binding proteins can read the base sequences of duplex dna by coming in contact with atoms either in minor or major groove. This is a comparison of the differences between dna versus rna, including a quick summary and a detailed table of the differences. Chemical structure of dna varsha butola 1, revathi b 2, anila g 3 and sravan kumar p 4. The sugar and phosphate groups combined form the repeating backbone of the dna strands. The chemical structures for these compounds are shown here.
Chapter 8 the chemical reactions of dna damage and degradation kent s. The sanger dna sequencing method uses dideoxy nucleotides to terminate dna synthesis. The polynucleotide chain is formed by joining of ribonucleotides, with the help of 3 5 phosphodiester bonds in the same fashion as in case of dna. Nucleic acid, naturally occurring chemical compound that is capable of being broken down to yield phosphoric acid, sugars, and organic bases. Yielding a series of dna fragments whose sizes can be measured by electrophoresis. Heredity structure and composition of dna britannica. Pdf structure and chemical composition of nucleic acid. The genetic code is the sequence of bases on one of the strands.
The double helix model of dna deoxyribonucleic acid consists of two intertwined strands. Chemical composition of dnaencoded libraries, past. Sep 04, 2016 structure of dna structure of a nucleotide structure of deoxyribose sugar watson and cricks model phosphodiester bond also watch following video. Clearly, the structures of dna and rna are richer and more intricate than was at. Note the difference in groove width and the relative displacements of the base pairs from the central axis. A gene is a specific sequence of bases which has the information for a. Their main function is to maintain and transmit the genetic code.
Both dna and rna contain the purine nitrogenous bases adenine abbreviated a and guanine g and the pyrimidine cytosine c, but in dna a second pyrimidine is thymine t, whereas in rna it is uracil u. Dna, organic chemical of complex molecular structure found in all prokaryotic and eukaryotic cells. Chapter 4 chemical composition of the cell nucleic acids. Indeed, there is no one generic structure for dna and rna. It codes genetic information for the transmission of inherited traits. All dnas, regardless of their origin, contain equal numbers of purine and pyrimidine bases. Contour length represents the total length of the genomic dna in a cell. This chapter discusses the determination of dna base composition. Crick cavendish laboratory, cambridge, england contribution to the discussion of provirus. Structure and nomenclature of nucleic acids double helical dna structure the dna structure was determined by watson and crick in 1953. Dna has a negative charge that is proportional to its size.
Structure and chemical composition of dna this quiz is based on the physical structure and chemical composition of dna. It would be superfluous at a symposium on vi ruses to introduce a paper on the structure of dna with a discussion on its importance to the problem. Deoxyribonucleic acid as the name suggests its structure it is made up of deoxyribose sugar. Discuss how recombinant dna techniques may be used to correct a point m. This property enables dna to bend in order to form a complex with binding proteins. Dna synthesis reactions in four separate tubes radioactive datp is also included in all the tubes so the dna products will be radioactive. It codes genetic information for the transmission of inherited. In this study, chemical composition of cyperus rotundus rhizomes essential oil, and in vitro antioxidant, dna damage protective and cytotoxic activities as well as antibacterial activity against.
Without dna, we would all be nothing but clones of each other and there would be no genetic diversity. Chapter 4 chemical composition of the cell nucleic acids dna. A number of other nitrogenous bases have been identified in dna and rna, but these occur much less frequently. Therefore, dna is a very important component of life in general and plays a vital role in all of our lives. Hence, in any dna there is a pyrimidine nucleotide for each purine one. Does dna extraction affect the physical and chemical. How is the dna chemically designed to perform its role as genetic material. Elements form the basic building block of all matter 2. Since g c pairs consist of three hydrogen bonds, while a t pairs only have two hydrogen bonds, the temperature at which different dna molecules melt varies depending on their basepair sequences. This absorption can be monitored using a spectrophotometer.
Home dna structure of dna dna chemical composition. The phosphate and the sugar have the structures shown in figure 62. The tertiary structure of dna packing dna into small spaces e. This information is stored in the form of long polymer chains. Gates department of chemistry, university of missouri, columbia, mo 8.
Their creation is a continuous process, and a single protein chain can have 1015 amino acids added to it per second via the process outline above. Structure and chemical composition of nucleic acid dna. Its orientation, width, width between nucleotides, length and number of nucleotides per helical turn is constant. This page, looking at the structure of dna, is the first in a sequence of pages leading on to how dna replicates makes copies of itself, and then to how information stored in dna is used to make protein molecules. An enzyme, rna polymerase, transcribes dna into mrna messenger ribonucleic acid. Vecscreen national center for biotechnology information screens your dna sequence for potential vector sequence. Let us begin by considering the nature of the nucleotide, the fundamental building block of dna. Adenine is always opposite thymine, and cytosine is always oppostie guanine. To make exact copies of dna, the double helix ladder is untwisted and separates the two strands. Chapter 4 chemical composition of the cell free download as powerpoint presentation. The structure and function of nucleic acids biochemical society.
All of these features were described by watson and crick. Heredity heredity structure and composition of dna. Chemical agents that damage dna and the chemistry of dna degradation 334 8. A gene is a specific sequence of bases which has the information for a particular protein. Dna stores genetic information used for the synthesis of proteins including enzymes and is found in the nucleus and mitochondria. Dna forms there are several forms of dna double helices.
Structure and chemical composition of dna multiple choice. Structure and chemical composition of dna worksheet. While studying the nucleotide composition of native dnas differing in origin, chargaff noticed the following regularities. Dna, short for deoxyribonucleic acid, is the basic genetic material for everything. Dna base composition varied from 25% to 70% among different organisms. This material is aimed at 16 18 year old chemistry students.
Chemical composition, antioxidant, dna damage protective. The two strands of a dna molecule can be melted into single strands by heat, which breaks the hydrogen bonds between complementary bases. There are about 92 elements occurring naturally in nature 3. The synthesis of dna or rna oligonucleotides refers to the chemical synthesis of nucleic acid fragments with defined chemical structures or sequences in various sizes. Genes were known to be associated with specific character traits but their physical nature was unknown. Dna deoxyribonucleic acid is also known as the basic unit of nucleus which is present inside the cell. It deals with basic concepts related to dna chemistry and dna methods. Describe the biochemical composition, structure, and.
Deoxyribonucleic acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. Read this article to learn about the model, chemical composition and transformation experiments of dna. It does this by splitting apart the two strands that form the double helix. Well worth running before doing any other analysis. If dna is placed in an electrical field it will migrate towards the positive electrode the cathode if dna is electrophoresed through a gel, smaller pieces will migrate faster than larger pieces. The bases in dna absorb ultraviolet light at the wavelength of 260 nm. The chemical components of dna are arranged into groups called nucleotides, each composed of a phosphate group, a deoxyribose sugar molecule, and any. Chemical sequencing of dna this is a rapid method for chemical dna sequencing which is commonly used as ladder for footprinting reactions or for sequencing of short dna oligonucleotides. The structure of dna was described in 1953, leading to further understanding of dna replication and hereditary control of cellular activities. As we shall see in this chapter, there are in fact vari. These strands are made up of nucleotides, which themselves consist of three component parts. As the purpose of this post was primarily to examine the chemical structure of dna, the discussion of replication and protein synthesis has been kept brief and relatively simplistic. Muskhelishvili in both the bacterial nucleoid and the eukaryotic nucleus, dna is usually packaged as a negative super.
Occasionally an organism may contain modified bases such as 5methylcytosine or hydroxymethylcytosine. The nucleotide consists of a phosphate joined to a sugar, known as 2 deoxyribose, to which a base is attached. Alongside proteins, lipids and complex carbohydrates, nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life. The nature of dna modern genetic analysis ncbi bookshelf. Chapter 8 the chemical reactions of dna damage and. Dna is found in the cells of all the living organisms except in some plant viruses. Dna dna deoxyribonucleic acid dna is the genetic material of all living cells and of many viruses. For example, the chemical composition of metaphase chromosomes differs markedly from that of interphase chromatin, which contains relatively less dna but more protein and rna than the latter. Components fivecarbon sugar pentose called deoxyribose phosphate group nitrogenous base classification. Sep 30, 2011 what is the chemical composition of dna and rna. Although dna and rna both carry genetic information, there are quite a few differences between them.
Rnachemical compositionstructure usually ribonucleic acid rna is single stranded and made up of long, unbranched polynucleotide chain. In bacteriophages and viruses, there is a central core of dna which is enclosed in a protein coat. Changes in chemical composition attributable to dna extraction were measured on a separate set of 18 otolith pairs, nine from the dtu aqua archives fish caught in 1976 and nine from juvenile cod 0group reared in captivity fish sacrificed in 2007. The latter provides a nice output of mono, di and trinucleotide frequencies. The phosphoric acid component of each nucleotide is, of course, chemically identical in both nucleic acids.
1306 287 637 1157 704 383 611 1305 1423 710 509 318 1566 255 805 451 1266 1133 266 731 725 1074 1332 132 307 1443 313 259 114 204 68 1310 1378 201