Structure And Functions Of Dna And Rna Pdf

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This is a comparison of the differences between DNA versus RNA, including a quick summary and a detailed table of the differences. This table summarizes the key points:. Also, RNA is found in prokaryotes , which are believed to precede eukaryotes.

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RNA , abbreviation of ribonucleic acid , complex compound of high molecular weight that functions in cellular protein synthesis and replaces DNA deoxyribonucleic acid as a carrier of genetic codes in some viruses. RNA consists of ribose nucleotides nitrogenous bases appended to a ribose sugar attached by phosphodiester bonds, forming strands of varying lengths. The ribose sugar of RNA is a cyclical structure consisting of five carbons and one oxygen. The structure of the RNA molecule was described by R. Holley in RNA typically is a single-stranded biopolymer. However, the presence of self-complementary sequences in the RNA strand leads to intrachain base-pairing and folding of the ribonucleotide chain into complex structural forms consisting of bulges and helices.

Ribonucleic acid RNA is a polymeric molecule essential in various biological roles in coding , decoding , regulation and expression of genes. Along with lipids , proteins , and carbohydrates , nucleic acids constitute one of the four major macromolecules essential for all known forms of life. Cellular organisms use messenger RNA mRNA to convey genetic information using the nitrogenous bases of guanine , uracil , adenine , and cytosine , denoted by the letters G, U, A, and C that directs synthesis of specific proteins. Many viruses encode their genetic information using an RNA genome. Some RNA molecules play an active role within cells by catalyzing biological reactions, controlling gene expression , or sensing and communicating responses to cellular signals. One of these active processes is protein synthesis , a universal function in which RNA molecules direct the synthesis of proteins on ribosomes. Analysis of these RNAs has revealed that they are highly structured.

However, whereas DNA molecules are typically long and double stranded, RNA molecules are much shorter and are typically single stranded. RNA molecules perform a variety of roles in the cell but are mainly involved in the process of protein synthesis translation and its regulation. RNA is typically single stranded and is made of ribonucleotides that are linked by phosphodiester bonds. A ribonucleotide in the RNA chain contains ribose the pentose sugar , one of the four nitrogenous bases A, U, G, and C , and a phosphate group. The subtle structural difference between the sugars gives DNA added stability, making DNA more suitable for storage of genetic information, whereas the relative instability of RNA makes it more suitable for its more short-term functions. The RNA-specific pyrimidine uracil forms a complementary base pair with adenine and is used instead of the thymine used in DNA. Even though RNA is single stranded, most types of RNA molecules show extensive intramolecular base pairing between complementary sequences within the RNA strand, creating a predictable three-dimensional structure essential for their function Figure

The Differences Between DNA and RNA

If you're seeing this message, it means we're having trouble loading external resources on our website. To log in and use all the features of Khan Academy, please enable JavaScript in your browser. Donate Login Sign up Search for courses, skills, and videos. Practice: DNA questions. Molecular structure of DNA. Antiparallel structure of DNA strands. Leading and lagging strands in DNA replication.

The structure, function and evolution of proteins that bind DNA and RNA

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. The well-known structure of the DNA double helix allows this information to be copied and passed on to the next generation. In this article we summarise the structure and function of nucleic acids. The article includes a historical perspective and summarises some of the early work which led to our understanding of this important molecule and how it functions; many of these pioneering scientists were awarded Nobel Prizes for their work. We explain the structure of the DNA molecule, how it is packaged into chromosomes and how it is replicated prior to cell division.

The code within our DNA provides directions on how to make proteins that are vital for our growth, development, and overall health. DNA stands for deoxyribonucleic acid. DNA is a vitally important molecule for not only humans, but for most other organisms as well. But what does DNA actually do? The complete set of your DNA is called your genome.

Understanding biochemistry: structure and function of nucleic acids

Deoxyribonucleic acid, or DNA, is a molecule that contains the instructions an organism needs to develop, live and reproduce.

DNA: Definition, Structure & Discovery

DNA is the genetic material found in all living organisms, ranging from single-celled bacteria to multicellular mammals. It is found in the nucleus of eukaryotes and in the chloroplasts and mitochondria. In prokaryotes, the DNA is not enclosed in a membranous envelope, but rather free-floating within the cytoplasm. The entire genetic content of a cell is known as its genome and the study of genomes is genomics. In eukaryotic cells, but not in prokaryotes, DNA forms a complex with histone proteins to form chromatin, the substance of eukaryotic chromosomes. A chromosome may contain tens of thousands of genes.

DNA and RNA are remarkable because they can both encode information and possess desired properties, including the ability to bind specific targets or catalyze specific reactions. Nucleotide modifications that do not interfere with enzymatic synthesis are now being used to bestow DNA or RNA with properties that further increase their utility, including phosphate and sugar modifications that increase nuclease resistance, nucleobase modifications that increase the range of activities possible, and even whole nucleobase replacement that results in selective pairing and the creation of unnatural base pairs that increase the information content. These modifications are increasingly being applied both in vitro and in vivo , including in efforts to create semi-synthetic organisms with altered or expanded genetic alphabets.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Their functions include control of transcription and translation, DNA repair, splicing, apoptosis and mediating stress responses.


dimensions and there would be no minor and major grooves.) 9DNA Structure. Box DNA Has Base Pairs per Turn of the.


Key Points

А теперь не может отключить ТРАНСТЕКСТ и включить резервное электропитание, потому что вирус заблокировал процессоры. Глаза Бринкерхоффа чуть не вылезли из орбит. Мидж и раньше были свойственны фантазии, но ведь не. Он попробовал ее успокоить: - Джабба, похоже, совсем не волнуется. - Джабба - дурак! - прошипела. Эти слова его удивили. Никто никогда не называл Джаббу дураком, свиньей - быть может, но дураком - .

 На самом деле, - прервал его Дэвид, - Танкадо имел в виду первичную, а не главную разницу. Его слова буквально обожгли Сьюзан. - Первичное! - воскликнула. И повернулась к Джаббе.

Она поправила прическу. - Ты же всегда стремился к большей ответственности. Вот .

Он достал пистолет. Он выдвинул два стула на середину комнаты. Сел. Поднял посверкивающую полуавтоматическую беретту и нацелил ее на дверь, а потом опустил себе на колени. - Сьюзан, - сказал он торжественно.

Что привело вас в Севилью. - Я торговец ювелирными изделиями. Жемчугами из Майорки. - Неужели из Майорки. Вы, должно быть, много путешествуете.

 Вас это смущает? - раздался у него за спиной звонкий голос.

 - Он замолчал, не зная, что сказать. Беккер терпеть не мог говорить с автоответчиком: только задумаешься, а тот уже отключился.  - Прости, не мог позвонить раньше, - успел сказать .

Сьюзан важно было ощущать свое старшинство. В ее обязанности в качестве главного криптографа входило поддерживать в шифровалке мирную атмосферу - воспитывать. Особенно таких, как Хейл, - зеленых и наивных. Сьюзан посмотрела на него и подумала о том, как жаль, что этот человек, талантливый и очень ценный для АНБ, не понимает важности дела, которым занимается агентство. - Грег, - сказала она, и голос ее зазвучал мягче, хотя далось ей это нелегко.

Сьюзан стала быстро закрывать файлы электронной почты Хейла, уничтожая следы своего посещения. Хейл ничего не должен заподозрить - .

Даже перепачканная сажей и промокшая, Сьюзан Флетчер производила более сильное впечатление, чем он мог предположить. - А коммандер? - спросил. Бринкерхофф покачал головой.

Дэвид Беккер исчез. Тремя пролетами ниже Дэвид Беккер висел на вытянутых руках над Апельсиновым садом с наружной стороны Гиральды, словно упражняясь в подтягивании на оконном выступе. Когда Халохот поднимался по лестнице, Беккер, спустившись на три пролета, вылез через один из проемов и повис на руках. Сделал он это как раз вовремя - убийца промчался мимо в ту же секунду. Он так торопился, что не заметил побелевших костяшек пальцев, вцепившихся в оконный выступ.

4 Response
  1. Marjorie R.

    ✓ Major Groove is Wide, Deep. ✓ This structure exists when plenty of water surrounds molecule and there is no unusual base sequence in DNA-Condition that.

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