• Kingdom
• Phylum
• Class
• Order
• Family
• Genus 
• Species

• To correctly name them
• To organize them n a logical manner that makes it easy for scientists to find

So that anyone in any country and pronounce them and understand what they mean.

• Way species are named
• Italics
• Genus first letter name uppercase
• Species (unique to each type of organism) all lowercase
• Ex: Ursus americanus, Homo sapien

• People interpret physical characteristics in different ways
• Mimicry (hard to differentiate two organisms who look exactly the same)

Based on genotype. 

• Allowed us to see evolutionary relationships among organisms
• The higher the level of taxon, the the farther back in time organisms' common ancestor of all the taxons

Study of evolutionary relationships among organisms.

OR...

Evolutionary history of a species. 

• Extremophiles (live in extreme conditions)
• Prokaryotic
• Cell wall w/o peptidoglycan
• Unicellular
• Auto or heterotroph (most hetero)
• Can live w/o oxygen
• Thought to be older than bacteria

• Ecologically diverse
• Can live in many types of environments
• Prokaryotic
• Thick, rigid cell wall with peptidoglycan
• Unicellular
• Auto or heterotroph

• All organisms have a nucleus
• 4 kingdoms: Protista, Fungi, Plantae, Animalia

Koch's Postulates

(there's 4 of them)

1. Pathogens can be isolated from infected host
2. Pathogens can be cultivated (grow or maintain in a culture) in a lab
3. When introduced to a new host, pathogens cause the same disease
4. Pathogen can be re-isolated from new host

• Humans (can be carriers by showing no symptom of disease, but can pass pathogen on)
• Animals (ex: swine flu)
• Soil
• Contaminated water and/or food
• Human feces

Pathogens are passed by direct contact

ex: common cold, the "kiss disease" [mono], STDs

Pathogens survive on objects handled by people

ex: athlete's foot

Produced by bacteria, harmful chemicals in the body that leads to negative side effects. They care carried through the body and can damage parts of the body. 

Monitor disease to prevent spreading 

• CDC-Centers for Disease Control
• WHO-World Health Organization

• Prevents and slows progression of diseases
• No memory of disease
• "1st line of defense"
• 2 ways of defending body
• 3 responses to invasion

• Skin-layers of dead and alive skin cells prevents invasion of microorganisms
• Chemical barriers: lysozyme, mucus, and stomach acid
• Stomach acid (HCl) kills bacterial consumed w/ food
• Mucus prevents bacteria from sticking to cells

Specific Immunity

• Occurs when pathogens get past non-specific immunity
• Develops while non-specific immunity is working
• Is more effective at attacking pathogens
• Involves Lymphatic System

Lymphatic System

• Organ system that filter lymph and blood
• Destroy pathogens
• Lymphatic organs include: lymph nodes, spleen, tonsils thymus gland, etc

• Antigens
• Phagocytes (macrophages)
• Lymphocytes (B-cells)
• Helper T-cells
• Cytotoxic T-cells

Types of Responses in Specific Immunity

• Antibody-mediated response
• Cytotoxic T-cell

A substance that causes an immune response. 

(ex: carbohydrate on the surface of a bacterial cell)

• Antibodies

• A protein the body makes to fight disease. Puts "post-its" on anything that is "bad" for the body for the body to kill. Known as neutralizing foreign objects
• Found in blood and other bodily fluids
• Specific for each antigen

• Make antibodies
• Present antigens in antigen-presenting complexes (APCs) 
• Develop into B-memory cells

Lymphocytes that activate and direct other immune cells. 

• Activate cytotoxic T-cells
• Determine B-cell identity

• Temporary immunity
• Antibodies (serum) are made by people or animals them transferred/injected into body
• Antibodies develop humans and animals that are already immune to a specific disease

• Long-term immunity
• Immune system is exposed to a weakened version of an infectious disease
• Creates memory cells

Polysaccaride secreted around cell wall of a bacterium which:

• Prevents cell from drying out
• Helps the cell attach to other surfaces
• Protects from the effects of antibiotics

Allow bacteria to transfer plasmids and attach to surfaces.

• Microscopic
• Hair-like

What are the three shapes of bacteria?

(That we were taught thus far)

• Gram + (positive) - peptidoglycan present in cell wall - w/o lipid layer - purple
• Gram - (negative) - little/no peptidoglycan present in cell wall - w/ lipid layer - pink
• Important for prescribing correct antibiotic

• Asexual reproduction
• divides two cells to be genetically identical
• Basically mitosis
• Occurs about every 20 minutes

Require oxygen for metabolism 

ex: cyanobacteria

Cannot have oxygen present during metabolism, often break down and release inorganic compounds

ex: arachea

• Arguably nonliving or living 
• Smallest known disease-causing structures
• Origin theory: Came from parts of cells.
• Outer protein layer of virus known as a "capsid"
• Can have either DNA or RNA (not both)