4.1 - The Gene: DNA Structure & Replication

Chargaff’s Rules

A:T and G:C

Photo 51

Shows the double helix structure of DNA

Nucleotide

Building block of nucleic acids, such as DNA or RNA

Deoxyribose sugar

5 carbon sugar

Phosphate group

contains phosphorus

Nitrogenous base

A, T, G, C

Purine

1 ring structure

Pyrimidine

2 ring structure

Adenine

Base: A

Cytosine

Base: C

Guanine

Base: G

Thymine

Base T

Hydrogen bond

Bonds that are between bases connecting nucleotides on DNA chains

Antiparallel

Different directions, never touching

Double helix

Spiral structure of DNA

Conservative replication

Original DNA strand stays intact, acts as a template for new strand

Dispersive replication

Original DNA strand gets mixed up with the new one

Semi

conservative replication

DNA replication

Transcription and translation, results in duplicated DNA

DNA polymerase (DNA pol)

Enzyme in DNA replication, builds new strand

DNA helicase

Enzyme in DNA replication, separates the strands

DNA ligase

Binds Okazaki fragments to rest of the strand

RNA primase

Used at the beginning, gets replaced with DNA bases

Leading strand

Strand of DNA that can be made continuously during replication

Lagging strand

Strand of DNA that must be made in fragments during replication