What Are the Base Pairs in DNA and RNA?
Nov 13, · DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups . A base pair is two chemical bases bonded to one another forming a "rung of the DNA ladder." The DNA molecule consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
The base pairs in DNA are adenine to thymine and guanine to cytosine. In RNA, they are adenine to uracil and guanine to cytosine. A base pair is made of two nucleotides. These bonds are what hold the strand together in a double helix formation.
The double structure is a redundancy that acts as a backup system to store genetic information. Base pairs facilitate transcription, which is the process whereby genetic information encoded in DNA is transferred to RNA. The information is how to become a gm of a sports team in only one of the two strands of DNA, which is called the coding strand.
Every nucleotide in the coding strand has a complementary nucleotide in the other strand, wgat the template strand. In DNA, adenine bonds to thymine while guanine bonds with cytosine. The same pairs apply to RNA, except that uracil replaces thymine. Uracil and thymine molecules are very similar in shape, allowing them to pxirs the same kinds of hydrogen bonds with adenine.
There are, however, some alternate bond pairs which result whhat other hydrogen bonds. In a wobble base pair, guanine bonds to uracil, hypoxanthine bonds to uracil, hypoxanthine bonds to adenine, and hypoxanthine bonds to cytosine.
A Hoogsteen base pair is another alternate formation. Hoogsteens and wobbles occur most often in RNA and are highly complex. More From Chemkcal. What Is Aristocracy? What Do Stars Symbolize?
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What are the chemical components of DNA? Article Shared By. ADVERTISEMENTS: DNA has a sugar-deoxyribose, 4 type of nitrogen bases-adenine, guanine, cytosine and thymine and phosophate. The Sugar molecule in DNA is basically a ribose sugar. The ribose sugar is a . Mar 24, · The sugar and phosphate groups combined form the repeating ‘backbone’ of the DNA strands. There are four different bases that can potentially be attached to the sugar group: adenine, thymine, guanine and cytosine, given the designations A, T, G and C. The bases are what allows the two strands of DNA to hold together. The Tm is used to estimate the G+C content of a DNA molecule G-C base pairs are held together by three hydrogen bonds (A-Ts by two) and it therefore takes more energy (higher temperatures) to separate molecules with high GC contents.
Deoxyribonucleic acid DNA is a molecule that contains the biological instructions that make each species unique. DNA, along with the instructions it contains, is passed from adult organisms to their offspring during reproduction.
In organisms called eukaryotes, DNA is found inside a special area of the cell called the nucleus. Because the cell is very small, and because organisms have many DNA molecules per cell, each DNA molecule must be tightly packaged. This packaged form of the DNA is called a chromosome. At other times in the cell cycle, DNA also unwinds so that its instructions can be used to make proteins and for other biological processes.
But during cell division, DNA is in its compact chromosome form to enable transfer to new cells. An organism's complete set of nuclear DNA is called its genome. Besides the DNA located in the nucleus, humans and other complex organisms also have a small amount of DNA in cell structures known as mitochondria.
Mitochondria generate the energy the cell needs to function properly. In sexual reproduction, organisms inherit half of their nuclear DNA from the male parent and half from the female parent. However, organisms inherit all of their mitochondrial DNA from the female parent. This occurs because only egg cells, and not sperm cells, keep their mitochondria during fertilization. DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases.
To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating. The four types of nitrogen bases found in nucleotides are: adenine A , thymine T , guanine G and cytosine C. The order, or sequence, of these bases determines what biological instructions are contained in a strand of DNA.
The complete DNA instruction book, or genome, for a human contains about 3 billion bases and about 20, genes on 23 pairs of chromosomes. DNA contains the instructions needed for an organism to develop, survive and reproduce. To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the work in our bodies.
Each DNA sequence that contains instructions to make a protein is known as a gene. The size of a gene may vary greatly, ranging from about 1, bases to 1 million bases in humans. Genes only make up about 1 percent of the DNA sequence. DNA sequences outside this 1 percent are involved in regulating when, how and how much of a protein is made. DNA's instructions are used to make proteins in a two-step process. First, enzymes read the information in a DNA molecule and transcribe it into an intermediary molecule called messenger ribonucleic acid, or mRNA.
Next, the information contained in the mRNA molecule is translated into the "language" of amino acids, which are the building blocks of proteins. This language tells the cell's protein-making machinery the precise order in which to link the amino acids to produce a specific protein. This is a major task because there are 20 types of amino acids, which can be placed in many different orders to form a wide variety of proteins. But nearly a century passed from that discovery until researchers unraveled the structure of the DNA molecule and realized its central importance to biology.
For many years, scientists debated which molecule carried life's biological instructions. Most thought that DNA was too simple a molecule to play such a critical role. Instead, they argued that proteins were more likely to carry out this vital function because of their greater complexity and wider variety of forms. By studying X-ray diffraction patterns and building models, the scientists figured out the double helix structure of DNA - a structure that enables it to carry biological information from one generation to the next.
Despite his scientific achievements, Dr. Scientist use the term "double helix" to describe DNA's winding, two-stranded chemical structure. This shape - which looks much like a twisted ladder - gives DNA the power to pass along biological instructions with great precision. To understand DNA's double helix from a chemical standpoint, picture the sides of the ladder as strands of alternating sugar and phosphate groups - strands that run in opposite directions.
Each "rung" of the ladder is made up of two nitrogen bases, paired together by hydrogen bonds. Because of the highly specific nature of this type of chemical pairing, base A always pairs with base T, and likewise C with G. So, if you know the sequence of the bases on one strand of a DNA double helix, it is a simple matter to figure out the sequence of bases on the other strand. DNA's unique structure enables the molecule to copy itself during cell division.
When a cell prepares to divide, the DNA helix splits down the middle and becomes two single strands. These single strands serve as templates for building two new, double-stranded DNA molecules - each a replica of the original DNA molecule. In this process, an A base is added wherever there is a T, a C where there is a G, and so on until all of the bases once again have partners.
In addition, when proteins are being made, the double helix unwinds to allow a single strand of DNA to serve as a template. This template strand is then transcribed into mRNA, which is a molecule that conveys vital instructions to the cell's protein-making machinery. Where is DNA found? What is DNA made of? What does DNA do?
How are DNA sequences used to make proteins? Who discovered DNA? What is the DNA double helix? Related Contents. Last updated: August 24,