Which nucleotide always pairs with adenine

Base pair describes the relationship between the building blocks on the strands of DNA. And each of the nucleotides on one side of the strand pairs with a specific nucleotide on the other side of the strand, and this makes up the double helix. So for example, if there's a G on one side of the strand, there will always be a C on the other. If there's a T on one side of the strand, there will always be an A on the other.

At the metaphase stage of mitosis, when the chromosomes are lined up in the center of the cell, the chromosomes are at their most compacted. They are approximately nm in width, and are found in association with scaffold proteins. In interphase, the phase of the cell cycle between mitoses at which the chromosomes are decondensed, eukaryotic chromosomes have two distinct regions that can be distinguished by staining. There is a tightly packaged region that stains darkly, and a less dense region.

The darkly staining regions usually contain genes that are not active, and are found in the regions of the centromere and telomeres. The lightly staining regions usually contain genes that are active, with DNA packaged around nucleosomes but not further compacted. Concept in Action. Watch this animation of DNA packaging. The DNA molecule is a polymer of nucleotides. Each nucleotide is composed of a nitrogenous base, a five-carbon sugar deoxyribose , and a phosphate group. There are four nitrogenous bases in DNA, two purines adenine and guanine and two pyrimidines cytosine and thymine.

A DNA molecule is composed of two strands. Each strand is composed of nucleotides bonded together covalently between the phosphate group of one and the deoxyribose sugar of the next. From this backbone extend the bases. The bases of one strand bond to the bases of the second strand with hydrogen bonds. Adenine always bonds with thymine, and cytosine always bonds with guanine. Nucleotides are represented by different colored rectangles: red for thymine, blue for guanine, green for adenine, and orange for cytosine.

Below the sequenced strand, examples of truncated strands from the four reactions are shown. Reading the sequence: Now and then. How is DNA sequencing used by scientists? In recent years, DNA sequencing technology has advanced many areas of science. For example, the field of functional genomics is concerned with figuring out what certain DNA sequences do, as well as which pieces of DNA code for proteins and which have important regulatory functions. An invaluable first step in making these determinations is learning the nucleotide sequences of the DNA segments under study.

Another area of science that relies heavily on DNA sequencing is comparative genomics, in which researchers compare the genetic material of different organisms in order to learn about their evolutionary history and degree of relatedness. DNA sequencing has also aided complex disease research by allowing scientists to catalogue certain genetic variations between individuals that may influence their susceptibility to different conditions. How can all people benefit from DNA sequencing?

More about sequencing. DNA sequencing technologies Sequencing the human genome. Watch this video for a summary of the Sanger sequencing process. How much does gene sequencing cost? How was the human genome sequenced? What happens during DNA replication? Who, exactly, discovered DNA? How has the polymerase chain reaction PCR revolutionized biotechnology?

What has genomics done for the biofuel industry? What ethical problems does DNA sequencing raise? How is sequencing done on a large scale?

Who was Frederick Sanger? Key Concepts Human Genome Project bioinformatics genome. Topic rooms within Genetics Close. No topic rooms are there. The backbone of DNA consists of phosphodiester bonds made up of interchanging phosphate groups and deoxyribose sugars. Guanine and cytosine are bonded together by three hydrogen bonds; whereas, adenine and thymine are bonded together by two hydrogen bonds.

DNA is a chain of two strands of nucleotides that are linked to one another through hydrogen bonds and arranged into a structure known as a double-helix. This is why DNA is considered antiparallel. When determining the complementary strand, remember that it will be written in the opposite direction of the template strand. This means that the new strand's 5' end will begin at the 3' end of the template strand. To see these pairs match up, the 3' end of the answer must align with the 5' end of the template.

The difference between these classes is the structure of the base. Purines have two rings in their structure, while pyrimidines have only one. Purines will pair with pyrimidines. The purines are adenine and guanine, and the pyrimidines are thymine, cytosine, and uracil.

You can remember that the bases that contain a "y" are p y rimidines th y mine and c y tosine. There are four nitrogenous bases in DNA: adenine, guanine, cytosine, and thymine.

A nucleotide is composed of one of these bases bound to a deoxyribose sugar and a phosphate group. Polymers of nucleotides form strands of DNA, which adhere to one another by hydrogen bonding between the bases.

Each strand of DNA is unique and may contain any ratio of the nitrogenous bases, but strands of DNA will always be complementary to one another. The structure of the bases requires that adenine bind to thymine and cytosine bind to guanine to maintain the structural integrity of the DNA molecule. RNA does not contain thymine, and instead uses uracil.

There are four bases in DNA: adenine, thymine, guanine, and cytosine. Adenine always pairs with thymine, so the number of adenine residues always equals the number of thymine residues. Guanine always pairs with cytosine, which means they are always present in equal amounts as well.

If one strand contains three cytosine bases and five thymine bases, then the opposite strand must contain three guanine bases and five adenine bases. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

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