3.  Phosphate  Pentose sugar  Nitrogenous bases purine: adinine, guanine pyramidine: thymine, cytosine, uracil

4.  Helicase separates the DNA to form a replication fork at the origin of replication where DNA replication begins. HelicaseDNAorigin of replicationDNA replication  Replication forks extend bi-directionally as replication continues.  Okazaki fragments are formed on the lagging strand, while the leading strand is replicated continuously.lagging strandleading strand  DNA ligase seals the gaps between the Okazaki fragments.  Primase synthesizes an RNA primer with a free 3'-OH, which DNA polymerase III uses to synthesize the daughter strands.polymerase

7. 1. Nucleases enzyme i endonuclease ii exonuclease 2. Polymerase i. polymerase I (elongation 5’----- 3’) ii polymerase II iii polymerase III (initiation 5’----- 3’) 3. Ligase (5’ with 3’) 4. Primase 5. Gyrase 6. helicase

8.  Initiation  Elongation  Termination SENSE AND ANTISENSE DNA ?

9.  DNA polymerase makes very few errors, and most of those that are made are quickly corrected by DNA polymerase and other enzymes that "proofread" the nucleotides added into the new DNA strand. If a newly added nucleotide is not complementary to the one on the template strand, these enzymes remove the nucleotide and replace it with the correct one. With this system, a cell's DNA is copied with less than one mistake in a billion nucleotides. This is equal to a person copying 100 large (1000 page) dictionaries word for word, and symbol for symbol, with only one error for the whole process!