Answer:
B. Replication
Step-by-step explanation:
Definition:
- The process by which a double-stranded DNA molecule is duplicated to form two identical DNA molecules is known as replication. One of the most fundamental processes that happens within a cell is DNA replication. When a cell splits, the two daughter cells must have the same genetic information, or DNA, as the parent cell. To do this, each strand of existing DNA serves as a replication template.
DNA Replication:
The opening of the double helix and separation of the DNA strands, priming of the template strand, and construction of the new DNA segment are the three key phases in replication. The two strands of the DNA double helix uncoil at a precise place known as the origin during separation. Several enzymes and proteins next collaborate to prime the strands for duplication. Finally, a specific enzyme known as DNA polymerase coordinates the formation of new DNA strands. The following three-stage process description applies to all cells in general, however particular changes within the process may occur depending on organism and cell type.
Triggers of replication:
The start of DNA replication happens in two phases. First, a protein known as an initiator unwinds a small length of the DNA double helix. Then, an enzyme called helicase latches to and breaks the hydrogen bonds between the bases on the DNA strands, causing the two strands to separate. The helicase continues to break these hydrogen bonds and separate the two polynucleotide chains as it proceeds along the DNA molecule. Meanwhile, while the helicase divides the strands, another enzyme known as primase temporarily latches to each strand and builds a foundation for replication to begin. This foundation is a primer, which is a brief sequence of nucleotides.
DNA Strand Replication:
After the primer is placed on a single, unwinding polynucleotide strand, DNA polymerase wraps itself around that strand and adds additional nucleotides to the exposed nitrogenous bases. In this manner, the polymerase constructs a new DNA strand on top of the previous one. As DNA polymerase moves down the unwound DNA strand, it relies on the pool of free-floating nucleotides around the old strand to construct the new strand. The nucleotides in the new strand are coupled with partner nucleotides in the template strand; because to their chemical shapes, A and T nucleotides always pair with one another, and C and G nucleotides always pair with one another. This is referred to as complementary base pairing, and it leads in the formation of two complementary strands of DNA. Base pairing guarantees that the nucleotide sequence in the current template strand is perfectly matched to a complementary sequence in the new strand, also known as the template strand's anti-sequence. When the new strand is duplicated, its complementary strand will have the same sequence as the original template strand. As a result of complementary base pairing, the replication process occurs as a succession of sequence and anti-sequence copying that retains the original DNA's coding.
Time Replication Takes:
Replication in the prokaryotic bacteria E. coli may occur at a pace of 1,000 nucleotides per second. Eukaryotic human DNA, on the other hand, replicates at a pace of 50 nucleotides per second. Because different polymerases may synthesis two new strands at the same time utilizing each unwinding strand from the original DNA double helix as a template, replication proceeds so swiftly in both circumstances. One of these initial strands is known as the leading strand, and the other as the lagging strand. The leading strand is continually manufactured. The lagging strand, on the other hand, is produced in small, distinct pieces that are eventually linked together to create a full, freshly duplicated strand.