1. Classification, Bacteria, and Viruses
Biology 

2. Classification Taxonomy is:
the science of naming and classifying organisms
Linnaeus developed a two-word naming systems called binomial nomenclature.
Each species is assigned a two-part scientific name.
Written in italic, with just the first word capitalized
First word: Genus
Second word: species
For examples, humans are Homo sapiens

3. Classification
Overtime, Linnaeus’s classification/taxonomy system expanded to organize living things further. This includes:
Kingdom
Phlyum
Class
Order
Family
Genus
Species

4. Classification

5. Classification Cladogram-
a model used by evolutionary biologists to represent evolutionary history among species
Clade- a group of species that includes a single common ancestor and all descendants of that ancestor.
Derived character- a trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants.

6. Classification

7. Classification Classification has broaden beyond kingdoms to domains:
Bacteria
Archaea
Eukarya

8. Domain Bacteria Characteristics: Unicellular prokaryotes
Peptidoglycan cell wall, cell membrane, ribosomes
No membrane-bound organelles
Naked DNA, single circular chromosome
Asexual reproduction= binary fission
Heterotrophs, photoautotrophs, chemoautotrophs
Rods, spheres, spirals: Gram positive and gram negative

9. Domain Bacteria Domain Bacteria
Examples include: Bacillus, E. Coli, Streptococcus

10. Domain Archaea Characteristics Unicellular prokaryotes
Cell wall (no peptidoglycans), cell membrane, ribosomes, no membrane-bound organelles
DNA + histone proteins, single circular chromosome
Asexual reproduction = binary fission
Extremophiles: halophiles, thermophiles, methanogens

11. Domain Archaea
Examples:
Methancoccus, Halobacterium, Thermoproteus

12. Domain Eukarya Examples: Animals, Plants, Fungi, Protists
*We will explore each Kingdom in more detail throughout the remainder of the year 

13. Prokaryotes All bacteria are prokaryotes-
unicellular organism that lack a nucleus.
small cells (about 1-10 µm) that do not have membrane-bound organelles
Found in bacteria and archaebacteria

14. Prokaryotes Bacteria Archaebacteria
Surrounded by cell wall which contains peptidoglycan
Archaebacteria
Look similar to bacteria
Lack peptidoglycan in cell walls
Live in harsh environments

15. Bacteria Prokaryotic Cell Structures: Nucleoid region –
part of the prokaryotic cell where the DNA is found
Cell membrane –
innermost covering of the cell
Cell wall –
outside of cell membrane
Capsule –
outside of the cell wall, protective covering (not all bacteria have it)

16. Bacteria Prokaryotic Cell Structures (continued):
Flagella (sing. Flagellum) –
long, whiplike structure that moves bacteria
Endospore
A thick wall that encloses DNA; resistance structure enabling bacteria to survive harsh conditions
Pili –
short, hair-like projection used to stick to other surfaces and for conjugation (exchange of genetic materials between bacteria)
Cytoplasm –
jelly-like fluid that dissolves substances and holds organelles
Ribosomes –
organelles that make proteins in the cytoplasm

17. Bacteria

18. Bacterial cell walls
In bacteria, the cell wall consists of a protein/carbohydrate complex called carbohydrate called peptidoglycan. They are classified based on their cell walls:
Gram positive bacteria
More peptidoglycan in cell walls
Appear purple under the microscope after gram stain
Gram negative bacteria
Have less peptidoglycan in cell walls
Have outer membrane
Apper pink under the microscope after gram stain

19. Bacteria- shapes Bacilli Cocci Spirilla Rod-shaped
Spherical-shaped as either:
Staph- clusters
Strep-chains
Spirilla
Spiral-shaped

20. Bacteria-shapes

21. Bacteria- modes of nutrition
Heterotroph
Consume other organisms: Clostridium
Photoheterotroph
Consume other organisms and can use light energy: Rhodobacter
Photoautotroph
Use light energy to make carbon compounds; Cyanobacteria
Chemoautotroph
Use chemicals, like ammonia and hydrogen sulfide, to obtain energy; Nitrogen-fixing bacteria

22. Bacteria- Aerobic, Anaerobic, and Facultative Anaerobes
Need oxygen to live
Anaerobic
Cannot live with oxygen
Facultative anaerobes
Can live with or without oxygen

23. Bacteria- Binary Fission
Process by prokaryotes reproduce by cell division.
Steps:
Duplication of chromosomes and separation of copies.
Cell elongates
Divides into two daughter cells

24. Bacteria- Binary Fission

25. Bacteria and Disease
Pathology- the study of disease caused by pathogens (microorganism—viruses or prokaryotes– that cause disease)

26. Bacteria and disease
Bacteria cause disease by destroying living cells or by releasing chemicals that upset homeostasis.
Damaging host tissue
Releasing toxins

27. Bacteria and Disease Bacteria can be controlled via: Physical removal
Disinfectants
Food storage
Food processing
Sterilization by heat

28. Bacteria and Disease Bacterial diseases can be treated via-
Antibiotics
Blocks the growth and reproduction of bacteria
Examples: penicillin, streptomycin, and tetracycline

29. Bacteria and Disease Prevention of a bacterial disease via: vaccine-
A preparation of weakened or killed pathogens or inactivated toxins that prompt the body to produce immunity to a specific disease upon injection.

30. Virus Virus A nonliving particle made of proteins and nucleic acids.
Can reproduce only by infecting living cells.
Have no cytoplasm or organelles
Cannot carryout metabolism or homeostasis
Can’t grow like cells.

31. Virus Viruses consist of… Capsid- protein coat surrounding a virus
Some viruses have an envelop that surrounds the capsid (Influenza)
Nucleic acids (either DNA or RNA)

32. Virus Shapes Helical- Tobacco Mosaic Virus (contains RNA)
Polyhedral- Herpes (contains DNA) , Chicken Pox (contains DNA), Polio (contains RNA)
Spherical (enveloped)- Influenza (contains RNA)
Bacteriophage- T4 (contains DNA)
Spherical
Bacteriophage
Helical

33. Virus Viral Infections-
In order to infect a cell, a virus must be able to recognize it.
Viruses must bind the proteins on their capsid specifically to the proteins on their specific host.
Viruses then “trick” the cell to take in its genetic material.
Viruses will then make multiple copies of themselves inside the cell, ultimately destroying the cell.

34. Virus Viral Infections can take place in two ways- Lytic infection
Lysogenic infection

35. Virus
Lytic Infection
The virus infects a cell, it replicates, and the new viruses burst or “lyse” from the cell.

36. Virus Lysogenic Infection host cell is not immediately taken over
The virus infects a cell, the viral DNA integrates with host DNA where it may stay for a long period of time.
The viral DNA multiplies as the host cells multiply.
Eventually, it will become lytic, and the viruses will burst from the cell.

37. Viruses and Disease
Viruses cause disease by directly destroying living cells or by affecting cellular processes in ways that upset homeostasis. Diseases include:
Common cold
Influenza
AIDS
Chicken pox
Hepatitis
Wes Nile Virus
HPV (Human papillomavirus)

38. Viruses and Disease Ways to fight viruses- Hygiene- Vaccinations
Washing hands, avoiding contact with sick individuals, coughing or sneezing into a tissue or your sleeve
Vaccinations
Exposure to inactive forms of the virus that prompt the body to produce immunity to a specific disease upon injection.
Vector control
West Nile Virus is carried by mosquitoes (the vector). Controlling the population mosquitoes could eliminate the spread of the virus.
Antiviral drug therapy
Attack virual enzymes that in turn slow down or stop the infection cycle of the virus.