- DNA replication using the Watson and Crick DNA model, including nucleotide composition, pairing and bonding
- Assess the effect of the cell replication processes on the continuity of species
Learn.
DNA replication allows to identical copies of a genome to be made, hence the two daughter cells are genetically identical. This allows an organism to grow so it can reach maturity and pass on the genetic information. For asexual reproduction, this method of DNA synthesis also allows for the species to reproduce. For example bacteria use binary fission to form two genetically identical daughter cells.
For a high school understanding of this process, you should know Helicase is an enzyme which unzips the DNA base pairs, breaking the hydrogen bond between them which holds the double stranded helix together. Topoisomerase is also unwinding the DNA so it is no longer a double helix. Primase, DNA ligase and DNA polymerase then goes through and catalysis the addition of the corresponding opposite base pairs. For example, ATG would have the RNA-Primer TCG added, as we saw in the structure of DNA lesson.
The resulting product of the above process is two genetically identical DNA strands.
For a more comprehensive overview for a first year uni level understanding have a look at DNA Replication.
Memorize.
Helicase is an enzyme which unzips the DNA base pairs, breaking the hydrogen bond between them which holds the double stranded helix together. Topoisomerase is also unwinding the DNA so it is no longer a double helix. Primase, DNA ligase and DNA polymerase then goes through and catalysis the addition of the corresponding opposite base pairs. For example, ATG would have the RNA-Primer TAC added, as we saw in the structure of DNA lesson.
Master.
Question 1.
Explain the function of the helicase enzyme in DNA Replication. [3 mark]
Question 2.
Analyse how DNA replication allows for the continuation of a species using the example of bacteria and humans. [5 marks]
Answers.
Question 1.
The helicase acts to unzip the DNA, breaking the hydrogen bonds between the complimentary and coding strand of DNA. This forms two single strands of DNA from one double stranded DNA.