| Enzyme | Function | |--------|----------| | | Unwinds and separates the double helix by breaking hydrogen bonds. | | DNA Polymerase III | Synthesizes new DNA strands by adding nucleotides to the 3’ end; also has 3’→5’ proofreading ability. | | Primase | Synthesizes a short RNA primer to provide a 3’-OH group for DNA polymerase to begin adding nucleotides. | | Ligase | Seals nicks (joins Okazaki fragments) on the lagging strand by forming phosphodiester bonds. | | Topoisomerase | Relieves supercoiling ahead of the replication fork to prevent DNA breakage. |
| Purines (two rings) | Pyrimidines (one ring) | |---------------------|------------------------| | Adenine (A) | Cytosine (C) | | Guanine (G) | Thymine (T) | | (Also Uracil in RNA)| |
Why is DNA replication considered semiconservative ? Dna Structure And Function Worksheet Ap Biology Answer
Compare and contrast the leading strand and the lagging strand .
Semiconservative replication means that each new DNA double helix contains one original (parental) strand and one newly synthesized daughter strand . This was proven by the Meselson-Stahl experiment using isotopic nitrogen (¹⁵N and ¹⁴N). | Enzyme | Function | |--------|----------| | |
If one strand of DNA has the sequence 5’-ATTCGAGC-3’, what is the complementary strand? Be sure to label the 5’ and 3’ ends.
What type of bond holds the two strands of DNA together? Why is this bond important for DNA replication? | | Ligase | Seals nicks (joins Okazaki
The complementary strand is: 3’-TAAGCTCG-5’