Helicase

Helicase
•    Helicase is an enzyme that unwinds the two strands of DNA, allowing the cell to copy the genetic information stored in DNA. 
•    During DNA replication, helicase uses energy from ATP to separate the two strands by breaking the hydrogen bonds between complementary bases. 
•    The separation of the DNA strands creates a Y-shaped structure called the replication fork, where the exposed strands serve as templates for synthesising new DNA. 
•    As helicase moves along DNA, the molecule tends to become increasingly twisted ahead of the replication fork. Topoisomerases relieve this torsional stress and prevent DNA from becoming tangled or breaking. 
•    Once the strands are separated, the DNA replication machinery uses each exposed strand as a template to produce a new complementary strand. 
•    A recent study published in Nature Communications found that cells use a molecular safety catch to keep the DNA-copying machinery inactive until the appropriate chemical signal releases it.
DNA Replication: From DNA Organisation to Copying
•    DNA (Deoxyribonucleic acid) contains the biological instructions that determine the characteristics of an organism and is passed from parents to offspring during reproduction. 
•    In eukaryotic cells, DNA is primarily located in the nucleus, where it is tightly packaged with proteins to form chromosomes. The complete set of nuclear DNA is called the genome. 
•    DNA becomes more unwound and accessible when it needs to be replicated or when its genetic instructions are used for processes such as protein synthesis. During cell division, it becomes highly condensed into chromosomes to facilitate its accurate distribution to daughter cells. 
•    Mitochondria also contain a small amount of DNA known as mitochondrial DNA (mtDNA). Unlike nuclear DNA, mitochondrial DNA is generally inherited from the mother because the mitochondria retained in the fertilised egg are derived primarily from the egg cell. 
•    In sexual reproduction, offspring generally receive approximately half of their nuclear DNA from each parent, whereas their mitochondrial DNA is inherited through the maternal line.