Chapter 22: Prokaryotes - Bacteria and Archaea

What temperature range can prokaryotes live?

0-121 degrees celsuis

What are Koch's postulates and what are they used for?

1. Microbes present in diseased individuals, not healthy ones. 2. Organisms must be isolated and grown away from host. 3. Organisms from culture injected into healthy, disease should appear. 4. Repeat 1-3 with healthy individuals, disease should not appear.

How much biomass is estimated to be prokaryotic?

10% of world's biomass

How deep in the ocean have prokaryotes been found?

10km below surface

When were antibiotics discovered? What has been the effects of their overuse?

1928. Overuse led to antibiotic resistant strains

The oldest fossils we have are from which domain of life?

3.5 billion year old bacteria. Eukaryotes (1.7 years later).

Where do prokaryotes live?

400 species in digestive tract, 128 species in stomach, 500 species in mouth. 10^13 human cells in body. 10^12 bacteria cells on skin, 10^14 in digestive tract.

How many species of bacteria have been named? How many are likely?

5000 named. Millions are likely

What is meant by pathogenic bacteria?

A bacteria that causes disease

What is virulence and why is it important to humans?

Ability to cause disease. Varies among individuals in a population. Escherichia coli, virulence depends on length of genome

What Archaean pathogen affects humans?

Affects tissue at entry points

What caused the tremendous decline in mortality rates after 1900?

Antibiotics and sanitation

What is the difference between an autotrophic and heterotrophic bacteria?

Autotrophic = makes own food Heterotrophic = eats other

What does a chemolithotroph eat?

Oxidize inorganic molecules. Cellular respiration with inorganic compounds as e donor.

What does a chemoorganotroph eat?

Oxidize organic molecules. Cellular respiration or fermentation.

Which are older: Archaea or Bacteria?

Bacteria

What is the difference between Bacteria and Archaea?

Bacteria = cell membrane contains ester bonds; cell wall made of peptidoglycan; have only one RNA polymerase; react to antibiotics in a different way than archea do. Archaea: cell membrane contains ether linkages; cell wall lacks peptidoglycan; genes and enzymes behave more like Eukaryotes; have three RNA polymerases like eukaryotes; and extremophiles

Who discovered Archaea?

Carl Woese

What is an enrichment culture used for? What is its purpose?

Cells sampled from environment

Are Archaea more closely related to Bacteria or Eukarya?

Eukarya

Name three differences between gram-positive and gram-negative bacteria?

Gram positive = purple, contains mostly carbohydrates and peptidoglycan. Gram negative = pink, thin layer of peptidoglycan, contains outer phospholipid layer

Bacteria are ancient, diverse, abundant, and ubiquitous. What does that mean?

Have been found for a long time and everywhere

Were the first bacteria thought to be autotrophic or heterotrophic?

Heterotrophic

What are the steps of the process of direct sequencing?

Isolate specific genes, sequence genes: ATCG, compare sequence with database, if sequence "significantly" differs - then you may have a new species -

Name three ways researching extremophiles are important to biologists?

May help explain how life on Earth began. Serve as model organism for search for extraterrestrial life. Enzymes found help DNA research

What does a photoautotroph eat?

Photophosphorylation. Electrons to top of electron transport chain.

How are bacterial species found using direct sequencing?

Phylogenetic species concept. distinguishing between different sequences of DNA molecules

Who is credited with the Germ theory of disease?

Robert Koch (1800s)

How did Carl Woese redraw the "tree of life"?

Showed division between prokaryotes and eukaryotes to be incorrect. Argued that the tree of life has three main branches. Added Archea, Bacteria as oldest, and Archaea and Eukaryotes more closely related.

Bacteria and Archaea are prokaryotic. What does that mean?

They lack a membrane bound nucleus

Describe how bacterial species are described?

grown under specific conditions. temp. lighting. substrate. food

What is meant by the word "extremophile"?

is an organism that thrives in extreme environments. High-salt High or low temperature High pressure

Why did the five kingdom of biological classification fall out of favor?

not a 5 kingdom system - a 3 domain system