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Viruses: Living or Non Living?

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Presentation on theme: "Viruses: Living or Non Living?"— Presentation transcript:

1 Viruses: Living or Non Living?
Phage = virus Bacteriophage = virus with bacteria host Virus = genetic info with protein shell

2 Viruses: Hershey – Chase Experiment

3 Viruses: Reproductive Cycle Lytic vs Lysogenic

4 Viruses: Retrovirus HIV: Retrovirus RNA instead of DNA
Enzyme reverse transcriptase Once in host, converts RNA into DNA (reverse transcription)

5 Viruses: Retrovirus Reverse Transcription

6 Classification: Domains
Major Division of Life: Prokaryotes vs. Eukaryotes

7 Domain: Archaebacteria
Archaea live in EXTREME conditions anaerobic swamps salt lakes acidic hot springs deep-sea hydrothermal vents animal digestive systems

8 Kingdom MONERA (Bacteria)
Prokaryotes - oldest life-forms Remain most numerous and widespread organisms on Earth today

9 Kingdom MONERA Prokaryotic: no nucleus, no organelles
Single-celled, Contains double-stranded circular chromosomal DNA Cell wall: peptidoglycan

10

11 Kingdom MONERA: Shapes
Spheres (cocci): most common Rods (bacilli) Curves or spirals

12 Kingdom MONERA Cyanobacteria: Bacteria: Autotrophs
Photoautotrophs and Chemoautotrophs Bacteria: heterotrophs

13 Kingdom MONERA: Genetic Engineering
Bacteria can reproduce both asexually (binary fission) and sexually This discovery led to the development of recombinant DNA technology a set of techniques for combining genes from different sources

14 Kingdom MONERA: Gene Exchanging
Can occur in 3 ways Transformation: taking up of DNA from the fluid surrounding the cell DNA enters cell Fragment of DNA from another bacterial cell Bacterial chromosome (DNA)

15 Kingdom MONERA: Gene Exchanging
Transduction: transfer of bacterial genes by phage (virus) Conjugation: union of cells and the DNA transfer between them Phage Fragment of DNA from another bacterial cell (former phage host)

16 Kingdom MONERA: Plasmids
Plasmid: a small circular DNA molecule separate from the bacterial chromosome

17 Kingdom MONERA: Genetic Engineering
Restriction enzymes cut DNA at specific points DNA ligase “pastes” the DNA fragments together The result is recombinant DNA

18 Kingdom MONERA: Recombinant DNA


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