BIO 024: Lesson 6 - Eukaryotes & Prokaryotes

Prokaryotic

DNA in found in the cytoplasm & circular plasmids

Prokaryotic

Not found inside the organelle

Prokaryotic

Consists of 1 copy of genome

Prokaryotic

Contains a small number of genes

Prokaryotic

Organized into single chromosomes

Prokaryotic

Not packed with histones and condenses to form nucleoid

Prokaryotic

Small amount of DNA in the form of a single circular chromosome

Prokaryotic

Introns are absent

Prokaryotic

DNA replication occurs in the cytoplasm

Prokaryotic

Chromosome contains single origin of replication

Prokaryotic

DNA replication is rapid

Eukaryotic

DNA is found in the nucleus of the cell, inside the chloroplast & mitochondira

Eukaryotic

Consists of more than 1 copy of genome

Eukaryotic

Contains of large number of genes

Eukaryotic

Organized into many chromosomes

Eukaryotic

Packed with histones to form chromatin

Eukaryotic

More DNA arranged in multiple linear chromosomes

Eukaryotic

Introns are present

Eukaryotic

DNA replication occurs in the nucleus

Eukaryotic

Chromosome contains many origin of replication

Eukaryotic

DNA replication is slow

Eukaryote

Contains one long, linear molecule of dsDNA

Chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Prokaryotic organism

Contains a single, double-stranded, supercoiled, circular chromosome

Nucleoid

Non-histone; A dense region of DNA in a prokaryotic cell.

Plasmid

Small, circular, extrachromosomal DNA molecules

Negative supercoiling

Unwinds the righthanded B-DNA double helix

Positive supercoiling

Overwinds B-DNA double helix

Topoisomerase

Enzymes that are involved in changing the supercoiled state of DNA

Class I topoisomerase

Cut the phosphodiester backbone of one strand of DNA, pass the other end through, and then reseal the backbone

Class II topoisomerase

Cut both strands of DNA, pass some of the remaining DNA helix between the cut ends, and then reseal

DNA gyrase

A bacterial topoisomerase that introduces negative supoercoils into DNA

Chromatin

Electrostatic attraction between the negatively charged phosphate groups on the DNA and the positively charged groups on the proteins results in

Histones

Principal proteins in chromatin

Nucleosome

Consists of DNA wrapped around a histone core