Chapter 18Genetics of Viruses and Bacteria

Viruses:• are much smaller than bacteria

•consist of a genome in a protective coat

•reproduce only within host cell

•use enzymes and ribosomes of host to make more viruses

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:Virus destroys host DNA, makes new viruses, digests cell wall

Lysogenic cycle:Virus inserts DNA into host genome (becoming a dormant prophage). Generations later, virus reactivates.

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lytic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

prophage

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Chapter 18Genetics of Viruses and Bacteria

Lysogenic cycle:

Animal Viruses:• are diverse in their means of infection

•often have an envelope acquired from cell membrane.

Chapter 18Genetics of Viruses and Bacteria

Retroviruses:• made of RNA

•use reverse transcriptase to make DNA from RNA template

•DNA inserts into host genome as dormant provirus.

Chapter 18Genetics of Viruses and Bacteria

Emerging viruses:•existing viruses that are expanding their host territory.

Chapter 18Genetics of Viruses and Bacteria

Viroids:•naked RNA

Prions:•infectious proteins

•mad cow disease.

Chapter 18Genetics of Viruses and Bacteria

Plasmids:•Small rings of DNA with accessory genes

Bacteria

Plasmids:•Small rings of DNA with accessory genes.

chromosome

plasmid

Bacteria

Transformation:

Bacteria

Transformation:•Bacteria take up naked DNA

Bacteria

Transformation:•Bacteria take up naked DNA

Bacteria

Transformation:•Bacteria take up naked DNA

Bacteria

Transduction:

Bacteria

Transduction:•Phages carry bacterial DNA

Bacteria

Transduction:•Phages carry bacterial DNA

Bacteria

Transduction:•Phages carry bacterial DNA

Bacteria

Transduction:•Phages carry bacterial DNA

Bacteria

Transduction:•Phages carry bacterial DNA

Bacteria

Conjugation:

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

Conjugation:•Bacteria “mate” to share DNA

Bacteria

The F-factor gives a bacteria the ability to conjugate

Bacteria

The F-factor gives a bacteria the ability to conjugate.

The F-plasmid carries the genes for sex pili.

Bacteria

Hfr cells (high frequency or recombination cells) have the F plasmid incorporated into the chromosome

Bacteria

Hfr cells (high frequency or recombination cells) have the F plasmid incorporated into the chromosome.

The F-factor of an Hfr carries other genes along with it.

Bacteria

R-plasmids carry antibiotic resistance.

Bacteria

Transposons are “jumping genes” that can move about in the genome.

.

Bacteria