DNA Part 1: DNA Structure and Replication
DNA Structure- Nucleotides 3 parts: Phosphoric acid (phosphate) Pentose sugar (deoxyribose) Nitrogen Base i) Adenine & Thymine ii) Guanine & Cytosine Complimentary base pairs
DNA Structure Phosphate- sugar backbone 2 strands twisted into double helix Hydrogen bonding between bases Large sections of DNA make up genes Genes determine which proteins are made in the body
Replication of DNA Purpose of replication: Copying 1 DNA helix into 2 DNA helices Cell division- Needed for growth/ repair Each cell needs exact copy Semi-conservative: one old strand and one new strand
Replication of DNA Process of replication: Enzyme DNA Helicase unwinds/ unzips Helix New complimentary DNA nucleotides bond (positioned & joined by DNA Polymerase) DNA Ligase seals any breaks in backbone
Summary What you need to know: 3 parts of a nucleotide 4 types of complimentary bases Steps in DNA Replication- 3 enzymes