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The primer always binds as the starting point for replication. Once the DNA strands have been separated, a short piece of RNA called a primer binds to the 3' end of the strand. The leading strand is the simplest to replicate. Replication Begins Step 2: Primer Binding The two sides are therefore replicated with two different processes to accommodate the directional difference. However, the replication fork is bi-directional one strand is oriented in the 3' to 5' direction (leading strand) while the other is oriented 5' to 3' (lagging strand). This directionality is important for replication as it only progresses in the 5' to 3' direction. The 5' end has a phosphate (P) group attached, while the 3' end has a hydroxyl (OH) group attached. This notation signifies which side group is attached the DNA backbone. This area will be the template for replication to begin.ĭNA is directional in both strands, signified by a 5' and 3' end. DNA helicase disrupts the hydrogen bonding between base pairs to separate the strands into a Y shape known as the replication fork. This is performed by an enzyme known as DNA helicase.

In order to unwind DNA, these interactions between base pairs must be broken. Adenine only pairs with thymine and cytosine only binds with guanine. DNA has four bases called adenine (A), thymine (T), cytosine (C) and guanine (G) that form pairs between the two strands. Science Photo Library / Getty Images Step 1: Replication Fork Formationīefore DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands. Prior to DNA replication, the chromatin loosens giving cell replication machinery access to the DNA strands. Chromatin condenses to form chromosomes during cell division. In order to fit within the nucleus, DNA is packed into tightly coiled structures called chromatin. This twisting allows DNA to be more compact. Double-stranded DNA consists of two spiral nucleic acid chains that are twisted into a double helix shape. It consists of a 5-carbon deoxyribose sugar, a phosphate, and a nitrogenous base. It is also vital in the cell repair process.ĭNA or deoxyribonucleic acid is a type of molecule known as a nucleic acid.

The overall DNA replication process is extremely important for both cell growth and reproduction in organisms.

Enzymes are vital to DNA replication since they catalyze very important steps in the process.

Replication involves the production of identical helices of DNA from one double-stranded molecule of DNA.

The process that copies DNA is called replication.

Since DNA contains the genetic material for an organism, it is important that it be copied when a cell divides into daughter cells.

Deoxyribonucleic acid, commonly known as DNA, is a nucleic acid that has three main components: a deoxyribose sugar, a phosphate, and a nitrogenous base.