Ebola E. coli Fungus from soil Phage virus This week: Microorganisms and Pathogens

CB 26.21

Bacteria ArchaeFungi Animals Protists Plants CB 1.15

CB 6.6 Prokaryotic cells: simple cells, no internal membranes

CB 27.2 Bacteria can be classified by cell shape

Different species of bacteria use different nutrition sources

lag exponential stationary Bacteria can divide rapidly CB 53.12

CB Human Population Growth

(3,000 days) CB Bacterial evolution. Faster reproduction in low nutrient conditions.

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

CB Some bacteria help provide nutrients for plants

The nitrogen cycle

Nitrogen as part of amino acids NNN

The nitrogen cycle

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

What do bacteria do? from a human perspective Good Decay dead material Help digest food Protect body from “bad bacteria” Provide nutrients Produce oxygen Bad Cause disease –Food poisoning –STD’s –Cavities –Infections of skin or body Spoil food/infect crops

Viruses

Viruses are very simple, and come in a variety of shapes/compositions CB 19.3

Living organisms must fit all of the following criteria: (modified from Campbell “Biology”) 1. They must have organization. 2. They must have metabolism. 3. They must respond to the environment. 4. They must be able to reproduce themselves.

Viruses only harm cells by invading them and using the cell to reproduce

Living organisms must fit all of the following criteria: (modified from Campbell “Biology”) 1. They must have organization. 2. They must have metabolism. 3. They must respond to the environment. 4. They must be able to reproduce themselves.

basic viral reproductive cycle CB 19.4

The Lytic Cycle CB 19.5

The Lytic and Lysogenic Cycles CB 19.6 Lytic cycle Lysogenic cycle

the relationship between viruses and disease

Membrane protein Viruses enter cells via specific membrane proteins; thus viral infections are usually cell specific.

Spanish flu of

How many people die from the flu in a “normal” year in the U.S.? ~36,000 About 90% are over 65 years old

Spanish flu of Killed between million people worldwide; 675,000 in the U.S. (2.5%-5% of world population) Infected 1/5 to 1/4 of world population Was most lethal to people years old

Spanish flu of People on their way to work suddenly developing the flu and dying within hours (Henig). One physician writes that patients with seemingly ordinary influenza would rapidly "develop the most viscous type of pneumonia that has ever been seen" and later when cyanosis appeared in the patients, "it is simply a struggle for air until they suffocate," (Grist, 1979). Another physician recalls that the influenza patients "died struggling to clear their airways of a blood-tinged froth that sometimes gushed from their nose and mouth," (Starr, 1976).

The high fatality rate from the Spanish flu was probably due to an immune system over-reaction

HIV, a retrovirus, infects Helper T-cells CB 19.8

HIV reproduction CB 19.8 Reverse Transcriptase: RNA to DNA

HIV has both a lytic and lysogenic cycle CB 19.8

Where did HIV come from, and where is the next HIVesque virus?

Ebola E. coli Fungus from soil Phage virus This week: Microorganisms and Pathogens