BIOL 110 Lecture Notes - Lecture 7: Prokaryote, Genetic Variation, Chromosome
Document Summary
Dna diversity analysis suggests that new bacteria evolve quite rapidly. Example: one teaspoon of common dirt can harbor 100+ million bacteria. Prokaryotes can divide in as little as 20 minutes. Have three factors that enable fast reproduction. Produce via binary fission - asexual cell division in which a prokaryotic chromosome replicates and the parent cell splits into approximately two equal daughter cells. Fast reproduction allows for short generation time (and thus faster relative evolution) compared to eukaryotes. Prokaryotes don"t alter between haploid and diploid states - meiosis and fertilization are irrelevant. Exact replication through binary fission doesn"t allow for genetic variation. Mutations and short generation times allow for vast genetic variation. Adaptive evolution is crucial to prokaryotic life. Eukaryotic cells average about 1000 times more dna than prokaryotic cells. Prokaryotic dna is concentrated in the nucleoid. Typically double-stranded dna arranged in a single large ring. Less dna that must be replicated allows for faster replication times.