Chapter 27 Prokaryotes

Prokaryote

Unicellular organisms that make up the domains archaea and bacteria; most abundant organism

Coccus/cocci

Spherical shaped prokaryotes

Bacillus/bacilli

Rod-shaped prokaryotes

Peptidoglycan

Polymer made of modified sugars linked by short polypeptides; used to build cell walls of bacteria

Gram positive

Bacteria that turn purple during gram staining; thick layer of pdg; less complex structure

Gram negative

Bacteria that turn pink during gram staining; thin layer of pdg; more complex structure

Hans Christian Gram

Developed gram staining procedure

Capsule

A dense, well defined shell made of polysaccharides or proteins; sticky and helps bacteria adhere

Flagella

Structure in prokaryotes that allows for taxis

Binary fission

Process through which prokaryotes reproduce

Horizontal gene transfer

Form of genetic recombination; DNA is combined from different sources

Transformation

DNA is taken from environment

Transduction

Phages insert DNA into the cell

Conjugation

DNA is transferred between two prokaryotic cells via sex pilus

Phototroph

Organisms that receive energy from light

Chemotroph

Obtain energy from chemicals

Autotroph

Produce their own food using CO2 or related compounds

Heterotroph

Require at least one organic nutrient

Photoautotroph

Organisms that receive energy from light

Chemoautotroph

Using inorganic chemicals to produce energy

Photoheterotroph

Using light and organic carbon compounds to produce energy

Chemoheterotroph

Using organic chemical and carbon compounds to produce energy

Obligate aerobe

Requires oxygen for cellular respiration

Obligate anaerobe

Oxygen is lethal to this organism; uses fermentation

Facultative anaerobe

Can use oxygen or fermentation to perform cell functions

***Thiomargarita namibiensis***

Largest bacterium; proteobacteria that can be seen with the naked eye, found on the coast of Namibia

***Helicobacter pylori***

Causes stomach ulcers; discovered by Barry Marshall who drank a culture to prove his point

**Barry Marshall**

Drank a culture of Helicobacter to prove it caused stomach ulcers

***Treponema pallidum***

Causes syphilis; spirochete

***Borrelia burgorferi***

Causes lyme disease; spirochete

***Streptomyces*** **spp**.

Found in soil, used to develop antibiotics; gram positive

***Bacillus anthracis***

Anthrax; gram positive

***Streptococcus pyogenes***

Causes strep and necrotizing fasciitis; gram positive

Extremophile

Microscopic organisms that thrive in extreme conditions

Halophile

Salt loving archaea

Thermophile

Heat loving archaea

**Psychrophile**

Cold loving archaea

**Mesophile**

Middle loving archaea

**Symbiosis**

an ecological relationship between organisms that live in close and intimate contact

**Symbiont**

Smaller participant in symbiosis

**Host**

Larger participant in symbiosis

**Mutualism**

Both parties benefit

**Commensalism**

One party benefits and the other is neither helped nor harmed

**Parasitism**

One party benefits and the other is harmed

**How can some archaeal cells withstand such extreme conditions**

They all have unique adaptations which help them sustain themselves in extreme conditions. Some of them include unique ways to harvest energy, endospores, and capsules

**What cell wall structure dictates the Gram stain result of a bacterium**

The thickness of the peptidoglycan layers found in bacteria

Endospores

formed in harsh condition, totem of undying for bacteria

**How is genetic diversity generated in prokaryotes**

Through mutations, transfer of DNA from another cell, and absorption of DNA from outside sources