During the process of replication, the double stranded DNA unwinds and parts itself by the action of enzyme called as Helicase. The unwinding or separation of DNA forms a replication bubble and at the edge of the replication bubble is the replication fork.
DNA replication starts at the point called as origin of replication or ORI at the replication fork. DNA polymerase is the enzyme that plays a key role in DNA replication. DNA continues to replicate until the entire new strand is not formed.
<u>Answer</u>: Cystic fibrosis is a genetic disorder that causes thick mucus secretions.
<u>Explanation</u>:
- <em>Cystic fibrosis</em> is a genetic disorder caused by mutations in a gene that makes a protein called CFTR (cystic fibrosis transmembrane regulator).
- The CFTR protein normally functions as a channel for transport of chloride ions in cells responsible for mucus production.
- A person suffering from cystic fibrosis produces abnormal CFTR protein or no CFTR protein at all.
- This is the reason that thick, sticky mucus is produced instead of the thin, watery kind.
