This is the strand of DNA where DNA polymerase can add DNA nucleotides towards the replication fork continuously. DNA polymerase adds nucleotides in the 5' to 3' direction so DNA polymerase can add nucleotides to make the leading strand while moving towards the replication machinery. The parental DNA template for the leading strand is 3' to 5' to be complementary to the leading strand. 

Leading strand

Okazaki fragments are replicated DNA strands formed on the strand being replicated away from the replication fork (template is 3' to 5'). These fragments are separated by RNA primers. Because the DNA polymerase is moving away from the replication fork it must form replicated strands in Okazaki fragments. 
These fragments are named after the Japanese scientists Reiji and Tsuneko Okazaki who discovered them. 

Okazaki Fragments

The replication fork is formed by helicase. It forms when the DNA strands have been separated to initiate DNA replication.
The replication bubble is formed from bidirectional DNA replication. If viewed via a microscope, it appears like a bubble in the DNA strand.

Replication Fork vs. Replication Bubble

The lagging strand is replicated discontinuously because its synthesis proceeds opposite of the replication fork. It is synthesized in fragments that are divided by RNA primers known as Okazaki fragments. 

Lagging Strand

- Lagging Strand
- Leading Strand
- Okazaki Fragment
- Replication Fork
- Replication Bubble

University of Wisconsin - Madison

DNA replication is the copying of the genome. It happens in prokaryotic, archaeal, eukaryotic and viral genomes. DNA replication is semiconservative. This describes how, during DNA replication, the DNA is separated and single strands serve as the template for the synthesized DNA. This was determined by Matthew Meselson and Franklin Stahl in 1958. 

DNA Replication

• DNA is the hereditary material of the cell  
• It is mostly formed in antiparallel DNA strands in a double helix with a 5' and 3' end. 

• DNA contains major and minor grooves. 

• DNA is formed from hydrogen bonds between the base pairs adenine and thymine and cytosine and guanine bases, respectively.

Deoxyribonucleic Acid (DNA)

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

The steps of DNA replication are shared between eukaryotes and prokaryotes. The steps of DNA replication are: 
1. Initiation
2. Elongation
3. Termination

The Steps of DNA Replication

While eukaryotes and prokaryotes have some differences between their processes of DNA replication, they share many of the same proteins needed for replication. These are: 

- DNA Polymerase
- Helicase
- Topoisomerase
- Sliding Clamp
- Primase
- Single-stranded binding protein
- Ligase

Enzymes Involved in DNA Replication

Key Components of DNA Replication

DNA Replication shares many of the same enzymes and components across organisms. However, there are key difference between many of them.

Here we designate the different types of DNA replication: 
- Prokaryotic DNA Replication
- Eukaryotic DNA Replication

Classifications of DNA Replication by the Domains of Life

Nucleotide function

1. Precursors for nucleic acid synthesis: DNA, RNA

2. ATP is the prime energy source for biologic processes, GTP is sometimes used
Molecular motors, active transport of solutes across membranes

3. Nucleotides can activate biomolecules for synthetic reactions: 
 - UTP activating glucose, CTP activating alcohol head groups
 - ATP activation in several reactions

4. Nucleotides and derivatives are important parts of many second messenger systems (Cyclic AMP, cyclic GMP )

5. ATP is a source of phosphate for kinase reactions

Seen in regulation
Glycogen synthesis and degradation
Glycolysis


Learn Before

Related

Learn After