Chapter 25: Bacteria and Archaea

Photoheterotrophs

________ obtain carbon from other organisms but use chlorophyll and other photosynthetic pigment to trap energy from sunlight.

Mutualism

________ is a symbiotic relationship in which both partners benefit.

Autotrophs

________ may be photoautotrophs, which obtain energy from sunlight, or chemoautotrophs, which obtain energy by oxidizing inorganic chemicals such as ammonia.

Bacterial pathogens

________ cause disease, but are usually not considered obligate parasites.

Chemotrophs

________ obtain energy from chemical compounds; phototrophs capture energy from light.

Plasmids

________ that have genes for antibiotic resistance are called R factors.

Cannulae

________ and hami are recently discovered hairlike appendages unique to archaea.

Prokaryotic cells

________ are very small and do not have membrane- enclosed organelles such as nuclei and mitochondria.

genetic material

In prokaryotes ________ can be exchanged by trans- formation, transduction, or conjugation.

Biofilms

________ are dense communities of microorganisms, in which cells adhere to one another on a surface.

Commensalism

In ________ one partner benefits, and the other is neither harmed nor helped.

archaea carry

Some bacteria and ________ on nitrogen fixation; that is, they reduce nitrogen in the atmosphere to ammonia.

Methanogens

________ are obligate anaerobes that produce methane gas from simple carbon compounds.

Transformation

In ________ a prokaryotic cell takes in foreign DNA released by another cell.

free living decomposers

They are mainly ________ that obtain both carbon and energy from dead organic matter.

Korarchaeota

________ have been found in terrestrial hot springs.

Louis Pasteur

________ demonstrated that sterilization prevented bacterial growth.

Prokaryotes

________ play essential ecological roles as decomposers and are important in recycling nitrogen and other nutrients.

Nanoarchaeota

________ has only one member to date, Nano­ archaeum equitans, a very small, extreme thermophile discovered in a hydrothermal vent.

Pili

________ also extend from the surface of some prokaryotes.

cellular respiration

Most bacteria are aerobic; that is, they require oxygen for ________.

Kochs postulates

________ are a set of guidelines developed by robert Koch to demonstrate that a specific pathogen causes specific disease symptoms:

Bacterial flagella

________ are structurally different from eukaryotic flagella; each flagellum consists of a basal body, hook, and filament.

cell walls

Most bacteria have ________ composed of peptidoglycan.

parasite benefits

In parasitism the ________, and the host is harmed.

own organic molecules

Most prokaryotes are heterotrophs that obtain carbon from other organisms; some are autotrophs that make their ________ from simple raw materials.

marine dwellers

The Crenarchaeota include many extreme thermophiles, archaea that can inhabit very hot, sometimes acidic, environments and archaea that are ________.

Biofilms

________ may include bacteria, archaea, protists, and fungi.

Prokaryotic cells

________ have several common shapes: spherical (cocci), rod- shaped (bacilli), and spiral.

prokaryotes

Some ________ have hairlike appendages called fimbriae.

genetic material

The ________ of a bacterium typically consists of a circular DNA molecule and one or more plasmids, smaller circular fragments of DNA.

Prokaryotes

________ reproduce asexually by binary fission (the cell divides, forming two cells), budding (a bud forms and sepa- rates from the mother cell), or fragmentation (walls form inside the cell, which then separates into several cells)

Prokaryotes

________ are assigned to domain Archaea and domain Bacteria.

Prokaryotic cells have several common shapes

spherical (cocci), rod-shaped (bacilli), and spiral

Prokaryotes reproduce asexually by binary fission (the cell divides, forming two cells), budding (a bud forms and sepa

rates from the mother cell), or fragmentation (walls form inside the cell, which then separates into several cells)

In prokaryotes genetic material can be exchanged by trans

formation, transduction, or conjugation