Chapter 19Microbial Models: The Genetics of Viruses and Bacteria - PowerPoint PPT Presentation
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Chapter 19Microbial Models: The Genetics of Viruses and Bacteria
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Host range: infection of a limited range of host cells (receptor molecules on ... heterotrophic flagellates; Trypanosoma (African sleeping sickness; tsetse fly) ... – PowerPoint PPT presentation
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Title: Chapter 19Microbial Models: The Genetics of Viruses and Bacteria
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- Chapter 19 Microbial Models The Genetics of
Viruses and Bacteria
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Viral structure
- Virus poison (Latin) infectious particles
consisting of a nucleic acid in a protein coat - Capsid (viral envelopes) DNA or RNA
- Bacteriophages (phages)
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Viral reproduction Lytic Cycle
- Host range infection of a limited range of host
cells (receptor molecules on the surface of
cells) - The lytic cycle 1- attachment 2-
injection 3- hydrolyzation 4- assembly 5-
release - Results in death of host cell
- Virulent virus (phage reproduction only by the
lytic cycle)
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Viral reproduction Lysogenic Cycle
- Genome replicated w/o destroying the host cell
- Genetic material of virus becomes incorporated
into the host cell DNA (prophage DNA) - Temperate virus (phages capable of using the
lytic and lysogenic cycles) - May give rise to lytic cycle
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Lysogenic Cycle
Animation
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RNA viruses
- Retroviruses transcribe DNA from an RNA template
(RNA---gtDNA) - Reverse transcriptase (catalyzing enzyme)
- HIV---gtAIDS
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Retrovirus (HIV)
- Animation
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Viroids and prions
- Viroids tiny, naked circular RNA that infect
plants do not code for proteins, but use
cellular enzymes to reproduce stunt plant growth - Prions infectious proteins mad cow
disease trigger chain reaction conversions a
transmissible protein
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Bacterial/Prokaryotic genetics
- Nucleoid region in bacterium densely packed
with DNA (no membrane) - Plasmids small circles of DNA
- Reproduction binary fission (asexual)
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Classification
- Kingdom Monera?
- Domain Bacteria
- Domain Archaea
- Shape cocci (sphere)
bacilli (rod) helical (spiral)
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Form and Function
- 1- Most have Flagella
- 2- some are Helical in shape (spirochetes)
- 3- some produce Slime- used to adhere in masses
- tooth decay
- 4-most have some sort of Taxis-movement away or
toward a - stimulus (chemotaxis, phototaxis,
magnetotaxis) - 5-Most have Endospores resistant cells for harsh
conditions - (250 million years!)
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Animal-like Protist
- 1- Groups lacking mitochondria early eukaryotic
link Giardia (human intestinal parasite severe
diarrhea) Trichomonas (human vaginal
infection) - 2- Euglenoids autotrophic heterotrophic
flagellates Trypanosoma (African sleeping
sickness tsetse fly)
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Animal-like Protist
- Alveolata membrane-bound cavities (alveoli)
under cell surfaces dinoflagellates
(phytoplankton) Plasmodium (malaria)
ciliates (Paramecium)
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Plantlike Protist-Algae
- Rhodophyta red algae no flagellated stages
phycobilin (red) pigment - Chlorophyta green algae chloroplasts gave rise
to land plants volvox, ulva
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Funguslike Protist
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