CHP 12: Molecular Structure of Chromosomes and Transposition

Bacterial Chromosome Structure

Circular and Single

Eukaryotic Chromosome Structure

Linear

Eukaryotic Chromosomes have…

Multiple origins of replication (oris)

Telomeres are at the ends of

Eukaryotic Chromosomes

Eukaryotic Genome

Includes all the genetic sequences in a cell and size varies by species

Bacterial Chromosomes have…

One origin of replication (ori)

Bacterial Chromosome Packaging

Bacterial chromosome is packaged to fit in a cell through formation of loops and supercoiling causing the chromosomes to be thicker, but shorter

Centromeres exist in

Eukaryotic chromosomes

Transposition

The movement of genetic sequences from one place to another within a genome (jumping genes)

Transposable elements

Sequences that can transpose themselves

Transposable Elements (TEs) are found in…

All types of organisms

What are the two types of transposition?

Simple and Retro

Simple Transpostion (transposons)

a transposable element is removed and moved to another site

Simple Transposition uses what enzyme?

Transposase

The recognition sites for transposase are..

Specific sequences in DNA called direct repeats and inverted repeats

Retrotransposition

DNA is transcribed to RNA, RNA is reverse transcribed to DNA

In retrotranspostion which two enzymes are used?

Reverse transcriptase and Integrase