BIOL1201 CH16

Bacteriophages

Viruses that infect bacteria, providing DNA evidence.

DNA

Polymer of nucleotides with a sugar-phosphate backbone.

Nucleotides

Building blocks of DNA, consisting of base, sugar, phosphate.

Chargaff's Rules

A=T and G=C in any species' DNA.

Double Helix

DNA structure with two strands twisted together.

Replication

Process of copying DNA to produce daughter molecules.

Semiconservative Replication

Each daughter DNA has one old and one new strand.

Origins of Replication

Sites where DNA strands separate to initiate replication.

Replication Fork

Y-shaped region where DNA strands are unwound.

Helicases

Enzymes that untwist the double helix during replication.

Single-strand Binding Proteins

Stabilize single-stranded DNA during replication.

Topoisomerase

Enzyme relieving strain in DNA during unwinding.

DNA Polymerases

Enzymes synthesizing new DNA strands at replication forks.

RNA Primer

Short RNA chain initiating DNA synthesis.

Okazaki Fragments

Segments of lagging strand synthesized discontinuously.

DNA Ligase

Enzyme joining Okazaki fragments together.

Nucleotide Excision Repair

Nuclease cuts and replaces damaged DNA sections.

Telomeres

Protective ends of linear DNA, preventing gene erosion.

Nucleoid

Region in bacteria where supercoiled DNA is found.

Chromatin

Complex of DNA and proteins in eukaryotic cells.

Histones

Proteins that package DNA into nucleosomes.

Nucleosome

DNA wrapped around a core of eight histones.

Euchromatin

Loosely packed chromatin, accessible for transcription.

Heterochromatin

Highly condensed chromatin, less accessible during interphase.