DNA polymerase
In molecular biology, DNA polymerases are enzymes that synthesize DNA molecules from
deoxyribonucleotides, the building blocks of DNA. These enzymes are essential for DNA
replication and usually work in pairs to create two identical DNA strands from a single
original DNA molecule. During this process, DNA polymerase "reads" the existing DNA
strands to create two new strands that match the existing ones.
Every time a cell divides, DNA polymerases are required to help duplicate the cell's DNA, so
that a copy of the original DNA molecule can be passed to each daughter cell. In this way,
genetic information is passed down from generation to generation.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from
its tightly woven form, in the process breaking the hydrogen bonds between the nucleotide
bases. This opens up or "unzips" the double-stranded DNA to give two single strands of DNA that can be used as templates for replication.
History
In 1956, Arthur Kornberg and colleagues discovered DNA polymerase I (Pol I), in Escherichia
coli. They described the DNA replication process by which DNA polymerase copies the base
sequence of a template DNA strand. Kornberg was later awarded the Nobel Prize in
Physiology or Medicine in 1959 for this work.
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the
building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases
present on each strand of the original DNA molecule. This pairing always occurs in specific
combinations, with cytosine along with guanine, and thymine along with adenine, forming
two separate pairs, respectively. By contrast, RNA polymerases synthesize RNA from
ribonucleotides from either RNA or DNA.
When synthesizing new DNA, DNA polymerase can add free nucleotides only to the 3' end of
the newly forming strand. This results in elongation of the newly forming strand in a 5'-3'
direction. No known DNA polymerase is able to begin a new chain (de novo); it can only add a
nucleotide onto a pre-existing 3'-OH group, and therefore needs a primer at which it can add
the first nucleotide. Primers consist of RNA or DNA bases (or both). In DNA replication, the
first two bases are always RNA, and are synthesized by another enzyme called primase
Function
.
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the
building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases
present on each strand of the original DNA molecule. This pairing always occurs in specific
combinations, with cytosine along with guanine, and thymine along with adenine, forming
two separate pairs, respectively. By contrast, RNA polymerases synthesize RNA from
ribonucleotides from either RNA or DNA.
When synthesizing new DNA, DNA polymerase can add free nucleotides only to the 3' end of
the newly forming strand. This results in elongation of the newly forming strand in a 5'-3'
direction. No known DNA polymerase is able to begin a new chain (de novo); it can only add a
nucleotide onto a pre-existing 3'-OH group, and therefore needs a primer at which it can add
the first nucleotide. Primers consist of RNA or DNA bases (or both). In DNA replication, the
first two bases are always RNA, and are synthesized by another enzyme called primase.
In molecular biology, DNA polymerases are enzymes that synthesize DNA molecules from
deoxyribonucleotides, the building blocks of DNA. These enzymes are essential for DNA
replication and usually work in pairs to create two identical DNA strands from a single
original DNA molecule. During this process, DNA polymerase "reads" the existing DNA
strands to create two new strands that match the existing ones.
Every time a cell divides, DNA polymerases are required to help duplicate the cell's DNA, so
that a copy of the original DNA molecule can be passed to each daughter cell. In this way,
genetic information is passed down from generation to generation.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from
its tightly woven form, in the process breaking the hydrogen bonds between the nucleotide
bases. This opens up or "unzips" the double-stranded DNA to give two single strands of DNA that can be used as templates for replication.
History
In 1956, Arthur Kornberg and colleagues discovered DNA polymerase I (Pol I), in Escherichia
coli. They described the DNA replication process by which DNA polymerase copies the base
sequence of a template DNA strand. Kornberg was later awarded the Nobel Prize in
Physiology or Medicine in 1959 for this work.
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the
building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases
present on each strand of the original DNA molecule. This pairing always occurs in specific
combinations, with cytosine along with guanine, and thymine along with adenine, forming
two separate pairs, respectively. By contrast, RNA polymerases synthesize RNA from
ribonucleotides from either RNA or DNA.
When synthesizing new DNA, DNA polymerase can add free nucleotides only to the 3' end of
the newly forming strand. This results in elongation of the newly forming strand in a 5'-3'
direction. No known DNA polymerase is able to begin a new chain (de novo); it can only add a
nucleotide onto a pre-existing 3'-OH group, and therefore needs a primer at which it can add
the first nucleotide. Primers consist of RNA or DNA bases (or both). In DNA replication, the
first two bases are always RNA, and are synthesized by another enzyme called primase
Function
.
Function
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the
building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases
present on each strand of the original DNA molecule. This pairing always occurs in specific
combinations, with cytosine along with guanine, and thymine along with adenine, forming
two separate pairs, respectively. By contrast, RNA polymerases synthesize RNA from
ribonucleotides from either RNA or DNA.
When synthesizing new DNA, DNA polymerase can add free nucleotides only to the 3' end of
the newly forming strand. This results in elongation of the newly forming strand in a 5'-3'
direction. No known DNA polymerase is able to begin a new chain (de novo); it can only add a
nucleotide onto a pre-existing 3'-OH group, and therefore needs a primer at which it can add
the first nucleotide. Primers consist of RNA or DNA bases (or both). In DNA replication, the
first two bases are always RNA, and are synthesized by another enzyme called primase.
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