DNA Replication

  • DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the basis for biological inheritance.

DNA Polymerase

  • DNA polymerase is an enzyme that synthesizes 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.

Single-Stranded Binding Protein

  • Single-stranded binding proteins are a class of proteins that have been identified in both viruses and organisms from bacteria to humans.


  • Topoisomerases are enzymes that participate in the overwinding or underwinding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure. During DNA replication and transcription, DNA becomes overwound ahead of a replication fork.

DNA Ligase

  • DNA ligase is a specific type of enzyme, a ligase, that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. It plays a role in repairing single-strand breaks in duplex DNA in living organisms, but some forms may specifically repair double-strand breaks.

Replication Fork

  • The replication fork is a very active area where DNA replication takes place. It is created when DNA helicase unwinds the double helix structure of the DNA. The replication fork looks like a fork in the road that is composed of a leading strand and a lagging strand of DNA.

Lagging Strand

  • A lagging strand is one of two strands of DNA found at the replication fork, or junction, in the double helix; the other strand is called the leading strand. A lagging strand requires a slight delay before undergoing replication, and it must undergo replication discontinuously in small fragments.

Okazaki Fragments

  • Okazaki fragments are short sequences of DNA nucleotides which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication.

Linear Chromosome

  • A linear chromosome is a type of chromosome, found in most eukaryotic cells, in which the DNA is arranged in multiple linear molecules of DNA. In contrast, most prokaryotic cells contain circular chromosomes, where the DNA is arranged in one large circular molecule.


  • A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighboring chromosomes. Its name is derived from the Greek nouns telos “end” and merοs “part”.
  • It is a reverse transcriptase- it copies a RNA to put the repeated sequence on the ends of linear chromosomes

DNA Repair

  • DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome.