VIRUSES(What the heck are they?)

2

The Common Cold Virus

  

3

Oh Goodness, My E. coli has a Virus!

Viruses and Bacteria

It's easy to mix these up since compared to us, both are

VERY SMALL.

Great link for size comparison!

Source: http://www.cellsalive.com/phage.htm

4

The basics Viruses are:

non-living much smaller than the smallest cell pieces of genetic coding (DNA or RNA) “gift-wrapped” in a protein coat

5

Diversity of Capsids

6

Diseases caused by viruses include:• Common cold• Flu• Polio• Rabies• Herpes (chickenpox,cold sores, genital)• Warts• Measles, Mumps• Ebola• AIDS

Viruses cannot be killed with antibiotics because they are not alive!

7

Antibodies attacking AIDS Virus

8

Diversity of Life

Introduction to Prokaryotes

9

Figure 13.27a

10

Figure 13.27b

11

Prokaryote Diversity

12

• Two types of Prokaryotic organisms: Eubacteria (bacteria) and Archaea

Visual Summary 15.3

Prokaryotes

Domain Bacteria Domain Archaea(e.g., extremophiles)

13

Archaea – Thermophiles in a Nevada geyser.

14

Archaea in a hot spring.

15

Archaea – Halophilesin seawater evaporatingponds near San Francisco Bay.

Salinity increases from3% to 20% during the production of salt.

16

Archaea(a.k.a. “Archaeabacteria)

        Prokaryotic (like eubacteria)        Biochemically resemble eukaryotic cells        Believed to be the ancestors of eukaryotic cells        Today: only live in harsh environments 

17

(Bacteria Review)

What do you already know about bacteria??

18

Bacteria on the tip of a pin.

19

• Major Episodes in the History of Life

Visual Summary 15.1

Millions of years ago

475570

1,0001,7002,5003,5004,500

Major Episode

Plants and fungi colonize landAll major animal phyla establishedFirst multicellular organismsOldest eukaryotic fossilsAccumulation of atmospheric 02

Oldest prokaryotic fossilsOrigin of Earth

20

ALL CELLS have

• Plasma membrane

• DNA

• ribosomes

Generalized structure of bacteria cell

22Figure4.5x2

23Bacterial shapes: cocci, rods, spirals

24Cyanobacteria or “blue-green algae”

25

Bacterial colonies growing in culture.

26

Detriments to Humans

• Bad breath, tooth decay

• Food poisoning

• Some are pathogenicpathogenic –

27

Some Diseases caused by bacteria

• Strep throat

• Cholera

• Tubercolusis

• “the plague”

• Anthrax

• Toxic shock syndrome

• Syphilis, Gonorrhea,

28

How cure bacterial infections?

(Antibiotics)(Antibiotics)

29

Discussion Question:Should we drop “bacteria bomb?”

• Are there benefits to bacteria that outweigh

their detriments to humans????

30

Benefits of Bacteria• Decomposers! chemical cycling• Cyanobacteria were original producers of oxygen

atmosphere ozone• Origins of mitochondria & chloroplasts

• Aid humans in digestion (E. coli)• Allow cows to digest cellulose (grass)

milk, ice cream, hamburgers!• Lactic acid fermentation

(yogurt, buttermilk, sauerkraut)

• bioremediation• Nitrogen “fixers” (to be explained in Unit IV!)