The Six Kingdoms Chapter 17 Viruses Microscopic particles

The Six Kingdoms: Chapter 17

Viruses: ® Microscopic particles that invade cells and cause disease ® Non-living because they do not grow or develop or carry out respiration; they can only reproduce inside living cells (called a host cell)

Structure of a virus: ® Nucleic acid core: either DNA or RNA ® Capsid: outer protein coat ® Tail fibers: used to attach to host cell

Viruses replicate in lytic or lysogenic cycles: (make a copy) ® Lytic cycle (active): ® Virus attaches to host cell ® Injects viral nucleic acid which destroys host’s DNA ® New viruses made inside the cell ® Host cell pops, releasing virus to infect other cells

Lytic Cycle:

Lysogenic Cycle: ® Viral DNA is joined with the host cell’s DNA (chromosomes) and can be passed on to daughter cells ® Virus ® is present but not active Explains why some diseases seem to go away only to reappear later and why some diseases don’t show up for many years

Lytic and Lysogenic Cycle: Amoeba sisters …

Examples of Viruses: ® HIV, flu, chicken pox, colds, hepatitis, measles ® Can you guess which diseases are caused by lysogenic cycles and lytic cycles?

® Vaccinations: Use weakened or dead form of a virus to create antibodies against the virus ® How do they work? ®

6 Kingdoms ® Archaebacteria ® Eubacteria ® Protist ® Fungi ® Plant ® Animal

Bacteria: ® Archaebacteria: Prokaryotes ® Hetero/autotrophic ® Most ancient kingdom – 3. 5 billion years ® Live in extreme environments (deep sea vents/swamps/no oxygen) ®

® Eubacteria: ® Prokaryotes ® Hetero/autotrophic ® Live everywhere (except extreme environments) ® Ex: Strep, Tetanus

Structure of a Bacterial Cell: ® Strong cell wall; prevents bursting ® DNA in single circular chromosome ® Plasmid: small ring of DNA

Bacteria replicate by Binary Fission ® Binary Fission: Bacteria reproduce by dividing in half

The importance of bacteria: ® Cause disease (pathogens) Ex: strep throat, tetanus, Lyme disease ® Fewer deaths from bacterial infections because of sanitation and hygiene ®

The importance of bacteria: ® Recycle nutrients through decomposition ® Foods: cheese, yogurt ® Medicines: produce antibiotics to kill bacteria ® Antibiotic resistance

Yes you need to know this!