Lecture 4: The Diversity of Life- Bacteria and Archaea

Tree of Life

Bacteria, Archaea, and Eukarya

What is the difference between archaea and bacteria?

Bacteria cell walls are made of peptidoglycan and archaea has complex RNA polymerase.

Extremeophiles

Live in extreme habitats

Pathogens

Bacteria that causes illness

Germ Theory of Disease

1. Passed from person to person

2. Transmitted by bites from animals

3. Ingested contaminated food or water

Bioremediation

Adding bacteria or archaea to clean polluted sites

Thermophile

lives in extreme habitats

What are the three types of genetic variation through gene transfer?

1. Transformation

2. Conjugation

3. Transduction

Transformation

DNA from the environment is taken and used

Conjugation

direct contact and DNA sharing between cells

Transduction

viruses pass genetic infomration

Pili

The tunnel between two cells in conjugation

Gram stain

used to differentiate bacterial species into separate groups on a cell wall

What is the difference between gram positive and gram negative?

gram positive results in a thick peptidoglycan wall, while gram negative results in a thinner pep-layer with an additional outer cell membrane.

What are the arrangements of bacterial colonies?

Diplo: two

Strepto: line

Staphylo: cluster

What are the shapes of bacterial colonies?

Coccus: circles

Bacillus: rods

Spirilla: spirals

What is the difference between autotrophs and heterotrophs?

Autotrophs make their own food while heterotrophs absorb organic molecules

What are the sources from which heterotrophs and autotrophs synthesize ATP?

Phototrophs, chemoorganotrophs, chemolithotrophs

Phototrophs

light is used to excite electrons

Chemoorganotrophs

oxidize organic molecules with high potential energy

Chemolithotrophs

oxidize inorganic molecules with high potential energy

What are Koch’s postulates?

1. The microbe must be present in individuals suffering from the disease and absent from healthy individuals

2. Organism must be isolated and grown away from the host

3. Symptoms should appear in another organism if disease is injected

4. If organisms from pure culture are injected into a healthy experimental animal, disease symptoms should appear