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Owing to the relatively short nature of the eukaryotic Okazaki fragment, DNA replication synthesis occurring discontinuously on the lagging strand is less efficient and more time-consuming than leading-strand synthesis. DNA synthesis is complete once all RNA primers are removed and nicks are repaired. Depiction of DNA replication at replication ...
Structure of double-stranded DNA, the product of DNA synthesis, showing individual nucleotide units and bonds. DNA synthesis is the natural or artificial creation of deoxyribonucleic acid (DNA) molecules. DNA is a macromolecule made up of nucleotide units, which are linked by covalent bonds and hydrogen bonds, in a repeating structure.
As DNA synthesis continues, the original DNA strands continue to unwind on each side of the bubble, forming a replication fork with two prongs. In bacteria, which have a single origin of replication on their circular chromosome, this process creates a "theta structure" (resembling the Greek letter theta: θ). In contrast, eukaryotes have longer ...
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. [2] Some eukaryotic organelles such as mitochondria also contain some DNA. Many eukaryotic cells are ciliated with primary ...
Helicase is an enzyme which breaks hydrogen bonds between the base pairs in the middle of the DNA duplex. Its doughnut like structure wraps around DNA and separates the strands ahead of DNA synthesis. In eukaryotes, the Mcm2-7 complex acts as a helicase, though which subunits are required for helicase activity is not entirely clear. [2]
S phase (Synthesis phase) is the phase of the cell cycle in which DNA is replicated, occurring between G 1 phase and G 2 phase. [1] Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved.
The eukaryotic genome is organized into a compact chromatin structure that allows only regulated access to DNA. The chromatin structure can be globally "open" and more transcriptionally permissive, or globally "condensed" and transcriptionally inactive. The former (euchromatin) is lightly packed and rich in genes under active transcription.