Bacteria: Genetic Basics

Shows a schematic rod-shaped bacterium and a rod-shaped bacterium as viewed through a tunneling electron microscope, highlighting various parts of each. Shows a schematic bacterium with both a bacterial chromosome and several plasmids.

Figure 7.4, page 106, Campbell's Biology, 5th Edition; part of figure 13.11, Purves's Life: The Science of Biology, 7th Edition

Bacterial Replication: Asexual Reproduction

Illustrates the process of DNA replication for a bacteria's circular chromosome.

Figure 18.10, page 331, Campbell's Biology, 5th Edition

Can Bacteria Have Sex?

Bacterial “Sex” is Discovered

Shows the results of growing each strain, as well as the mixture, on a minimal medium; only the mixture produces colonies.

Figure 18.11, page 331, Campbell's Biology, 5th Edition

Three Ways Bacteria Exchange DNA

  1. Transformation: the bacterium takes up of foreign DNA from its surroundings.
  2. Transduction: viruses carry bacterial genes from one bacterium to another.
  3. Conjugation: two temporarily joined bacteria directly transfer genetic material.

1. Transformation

Shows how a lysed bacterium can release DNA fragments that are then incorporated into other bacteria.

Figure 13.10(a), Purves's Life: The Science of Biology, 7th Edition

2. Transduction

Shows the processes of generalized and specialized transduction, in a side-by-side comparison.

Figure 18.12, page 332, Campbell's Biology, 5th Edition

3. Conjugation

Gives a colorized tunneling electron microscope view of conjugation. Schematically illustrates the various steps of and conditions for conjugation.

Figure 18.13, page 333, Campbell's Biology, 5th Edition; figure 13.12, Purves's Life: The Science of Biology, 7th Edition