Profile
Settings
Refer your friends
Sign out
DNA repair is one of the processes by which a cell keeps its genetic information intact. DNA repair ensures a species’ survival by allowing kids to inherit parental DNA as faithfully as possible. It also helps to maintain a person’s health.
Replication of DNA
DNA replication is the biological process of making two identical replicas of DNA from one original DNA molecule in molecular biology.
DNA replication is the most important aspect of biological inheritance in all living beings. This is required for cell division during tissue growth and repair, as well as ensuring that each new cell has its own copy of the DNA. Because the cell has the unique property of division, DNA replication is crucial.
How is DNA replicated?
Replication has three main steps: opening the double helix and separating the DNA strands, priming the template strand, and making the new DNA segment. During separation, the two strands of a double helix of DNA unwind at a very specific place called the origin. The strands are then ready to be copied by enzymes and proteins working together. Finally, the new DNA strands are assembled by a specific enzyme called DNA polymerase. The three-stage process described below applies to all cells, but particular changes within the process may occur depending on organism and cell type.
What sets off replication?
The replication of a double-stranded DNA molecule is depicted schematically. The molecule’s left side is double-stranded. A globular yellow structure depicting the protein helicase is coupled to the terminals of many nitrogenous bases on the bottom strand in the centre of the molecule. The double helix to the right of the helicase protein has opened and the top strand has separated from the bottom. A tiny portion of the newly replicated double-stranded DNA molecule may be seen on the right. To start DNA replication, you have to do two things. A short stretch of the DNA double helix is unwound first by a protein called an initiator. Following this, the helicase protein latches to the hydrogen bonds that are present between the bases on the DNA strands and breaks them. This results in the two strands of DNA becoming untangled. As it moves along the DNA molecule, the helicase keeps breaking hydrogen bonds and separating the two polynucleotide chains. Meanwhile, while the helicase divides the strands, another enzyme called primase attaches to each strand for a brief period of time and builds a foundation on which replication can begin. A primer is a short sequence of nucleotides that acts as the foundation of a DNA molecule.
How are DNA strands replicated?
DNA polymerase wraps itself around a single, unwound polynucleotide strand after the primer is in place, attaching new nucleotides to the exposed nitrogenous bases The polymerase then builds a new strand of DNA on top of the one that is already there. As DNA polymerase moves down the unwinding DNA strand, it uses the pool of free-floating nucleotides around the current strand to build the new strand. The nucleotides that make up the new strand are matched with partner nucleotides in the template strand; A and T nucleotides always pair with one another due to their chemical shapes, while C and G nucleotides always pair with one another. Complementary base pairing (Figure 4) is a process that results in the formation of two complementary strands of DNA. The anti-sequence of the template strand ensures that the sequence of nucleotides in the existing template strand is exactly matched to a complementary sequence in the new strand. When the new strand is duplicated again, the complementary strand will have the same sequence as the original template strand. Because the bases pair up with their opposites, replication happens as a series of sequence and anti-sequence copies that keep the original DNA’s coding.
Unit of replication definition , small unit of DNA replication
Replication is carried out by replisomes, which are huge protein complexes that carry out the replication process. DNA polymerase and other proteins essential for replication are found in the replisome. Helicases, primases, ligases, topoisomerases and other enzymes. The nucleotide is the smallest unit of DNA.
Conclusion
DNA replication and repair are crucial processes that ensure that a biological system’s genetic material is maintained. DNA is constantly replicated and divided, and errors can occur throughout this process. DNA replication is the process by which a cell copies the DNA in its genome. A cell must first copy (or replicate) its entire genome before dividing, ensuring that each daughter cell has its own complete genome.
