1 / 6

Molecular Genetics

Molecular Genetics. Eukaryotic and Prokaryotic Chromosomes. Eukaryotic Chromosomes. They are linear and organized in pairs They are replicated at many points along their length simultaneously

aubrie
Download Presentation

Molecular Genetics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Molecular Genetics Eukaryotic and Prokaryotic Chromosomes

  2. Eukaryotic Chromosomes • They are linear and organized in pairs • They are replicated at many points along their length simultaneously • Their number varies greatly from one organism to another, but humans have 46 chromosomes; 22 pairs plus an X and either a second X or a Y • Before replication, they are organized as chromatin

  3. Chromatin • DNA is wrapped around collections of proteins called histones • Histones carry a positive charge and DNA carries a negative charge, so they are held together by electrostatic attraction • 9 histones with DNA coiled twice around the 8 histone core is called a nucleosome

  4. Chromatid • Once replication is complete, the chromatin coils and condenses into the familiar chromosome (2 chromatid) that begins mitosis

  5. Prokaryotic Chromosomes • Prokaryotes are single celled organisms that lack membrane bound organelles , including a nucleus • DNA in prokaryotes is in the form of a single, double stranded loop, as opposed to the linear eukaryotic chromosomes • These “naked” loops of DNA attach to the inner membrane of the prokaryote • There are also small, free floating loops of DNA called plasmids

  6. Prokaryotic Replication – Binary Fission • They replicate in one, continuous sweep of polymerase enzymes moving in opposite directions • The bacteria grows to twice its normal size, the DNA loops separate and then the bacteria divides

More Related