![]() This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. The sugar and phosphate lie on the outside of the helix, forming the DNAs backbone. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.Īn important property of DNA is that it can replicate, or make copies of itself. DNA has a double-helix structure (Figure). Each strand consists of many nucleotides, each consisting of a sugar and phosphate group, which form the sugar-phosphate backbone of DNA, and a nitrogenous base. Nucleotides are arranged in two long strands that form a spiral called a double helix. ![]() Together, a base, sugar, and phosphate are called a nucleotide. Phosphodiester bonding between nucleotides forms the sugar-phosphate backbone, the alternating sugar-phosphate structure composing the framework of a. Each base is also attached to a sugar molecule and a phosphate molecule. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.ĭNA bases pair up with each other, A with T and C with G, to form units called base pairs. Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The backbone of DNA is made up of phosphate molecules that form bonds between ribose sugars (through condensation reactions) to link monomers together to form a. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. The phosphate group of one nucleotide bonds covalently with the sugar molecule of the next nucleotide, and so on, forming a long polymer of nucleotide monomers. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA). Nearly every cell in a person’s body has the same DNA. Before cell division, these chromosomes are duplicated (by DNA replication) and provide a complete set of chromosomes for each daughter cell, whereas a circular coiled DNA is located in the cytoplasm of a prokaryotic cell.DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. The eukaryotic DNA is organized into genetic structures called chromosomes. They postulated the Watson and crick model of the DNA double helix which is accepted worldwide. Note:- DNA was first isolated by Friedrich Miescher and its molecular structure was identified by Francis Crick and James Watson. The backbone of DNA is the portion which provides structural support to the two strands and is made up of alternating sugar and phosphate groups while nitrogenous bases face inside. According to the base pairing rule to make double-stranded DNA, adenine forms a base pair with thymine and cytosine forms a base pair with guanine. ![]() Hydrogen bonds are formed between the nitrogen bases. Two successive nucleotides are joined by covalent bonds called phosphodiester bonds present between the sugar of one nucleotide and phosphate of the alternating sugar phosphate. Each nucleotide is composed of one of the four nitrogen molecules containing nucleobases (cytosine, guanine, adenine or thymine), a deoxyribose sugar and a phosphate group. The two strands of DNA chain run in opposite directions to each other and are thus called antiparallel.Ĭomplete Answer:-DNA is a heteropolymer of deoxyribonucleotides, which are made up of a pentose sugar, nitrogenous bases and a phosphate moiety. Thus, two chains of sugar-phosphate backbones run side-by-side with complementary paired nitrogenous bases hydrogen bonding between them. Hint:-Deoxyribonucleic acid is a double helix structure composed of two polynucleotide chains that coil around each other to form a genetic molecule carrying genetic instructions for the growth, development and reproduction of organisms. ![]()
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