DNA is always read in the 5′ to 3′ direction, and hence you would start reading from the free phosphate and finish at the free hydroxyl group.

One new strand, which runs 5′ to 3′ towards the replication fork, is the easy one. This strand is made continuously, because the DNA polymerase is moving in the same direction as the replication fork. This continuously synthesized strand is called the leading strand.

3′ end/5′ end: A nucleic acid strand is inherently directional, and the “5 prime end” has a free hydroxyl (or phosphate) on a 5′ carbon and the “3 prime end” has a free hydroxyl (or phosphate) on a 3′ carbon (carbon atoms in the sugar ring are numbered from 1′ to 5′).

DNA polymerase will add the free DNA nucleotides using complementary base pairing (A-T and C-G) to the 3′ end of the primer this will allow the new DNA strand to form. Nucleotides cannot be added to the phosphate (5′) end because DNA polymerase can only add DNA nucleotides in a 5′ to 3′ direction.

Glossary:3′ (3-prime) A term that identifies one end of a single-stranded nucleic acid molecule. The 3′ end is that end of the molecule which terminates in a 3′ phosphate group. The 3′ direction is the direction toward the 3′ end.

For DNA replication, the base-pairing rule states that adenine always pairs with thymine, and cytosine always pairs with guanine. For transcription from DNA to mRNA, the base-pairing rule states that adenine in DNA always pairs with uracil in mRNA, and cytosine always pairs with guanine.

Okazaki fragments are the short sequences of deoxyribonucleotides, which are formed at the lagging strand during replication. These fragments are joined by DNA ligase.

The resulting short fragments, containing RNA covalently linked to DNA, are called Okazaki fragments, after their discoverer Reiji Okazaki.

Abstract. During DNA replication in eukaryotic cells, short single-stranded DNA segments known as Okazaki fragments are first synthesized on the lagging strand. The Okazaki fragments originate from ∼35-nucleotide-long RNA-DNA primers.

On the upper lagging strand, synthesis is discontinuous, since new RNA primers must be added as opening of the replication fork continues to expose new template. This produces a series of disconnected Okazaki fragments.

Okazaki fragments are short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections.

Why are leading and lagging strand primers removed rather than joined with Okazaki fragments? They contain nucleotides with 2’OH groups, and are targeted for excision by DNA Polymerase. Removal of the lagging strand primer leaves a gap in the one of the strand’s DNA sequences.

Why is there a problem replicating the ends of linear DNA? The primer used for lagging strand synthesis can’t be replaced because there is no available 3′ OH to add the replacement DNA on to. The telomeres represent large buffer zones of DNA sequence that do not code for biomolecules.

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.

lagging strand definition. In DNA replication, the strand that is synthesized apparently in the 3′ to 5′ direction, but actually in the 5′ to 3′ direction by ligating short fragments synthesized individually. Strand of DNA being replicated discontinuously. See also leading strand.

The lagging strand is synthesized discontinuously in short Okazaki fragments, each requiring its own primer. Termination of replication in bacteria involves the resolution of circular DNA concatemers by topoisomerase IV to release the two copies of the circular chromosome.

The leading strand is the strand of nascent DNA which is synthesized in the same direction as the growing replication fork. The synthesis of leading strand is continuous. The lagging strand, on the other hand, is the strand of new DNA whose direction is opposite to the direction of the growing replication fork.

The lagging strand is the DNA strand replicated in the 3′ to 5′ direction during DNA replication from a template strand. It is synthesized in fragments.

The leading strand is a single DNA strand that, during DNA replication, is replicated in the 3′ – 5′ direction (same direction as the replication fork). DNA is added to the leading strand continuously, one complementary base at a time.