process

• DNA replication is the production of two identical double-stranded molecules of DNA from one original double helix molecule. DNA replicates during interphase before cell division.
• The process of DNA replication is semi-conservative because the two strands in the original DNA molecule act as templates for the synthesis of two new complementary strands
• This results in 2 double-stranded DNA helix molecules each with an original strand and a new strand. This mechanism ensures that the genetic material is copied exactly every time.
• Step 1: Double helix unwinds The enzyme DNA helicase causes the double helix to unwind and separate by breaking the weak hydrogen bonds between the complementary base pairs as it moves along the molecule creating a replication fork.
• Step 2: Addition of nucleotides The enzyme primase adds a short RNA primer to template strand. This primer molecule initiates the enzyme DNA polymerase to add free DNA nucleotides (stored in the nucleus) along the template strand using the rules of complementary base pairing (A-T, C-G) to synthesise new strands
• STEP 2 CONTINUE: DNA polymerase facilitates the addition of new complementary DNAnucleotides in the 5’ to 3’ direction. This addition is continuous on theleading strand and in fragments on the lagging strand
• Step 3: Checking for replication errors Enzymes identify and correct mistakes that have occurred during DNA replication. Also, the primers are removed, and DNA polymerase replaces them with DNA nucleotides. Despite this, there are still mutation mistakes during replication.
• Step 4: Double helix rewinds The enzyme DNA ligase connects the sugar-phosphate backbones to ensure 2 continuous double strands. The DNA molecules rewind to form two double-stranded DNA helix molecules.