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44 Cards in this Set

  • Front
  • Back
What are microbes?
microscopic organisms
Total number of bacteria and archaea alive today?
5 X 10^30
3 domains of the tree of life?
Bacteria, Archaea, and Eukarya
Describe Bacteria.
Bacteria are prokaryotic. They have cell
walls made of peptidoglycan, plasma
membranes similar to those of eukaryotes,
and distinct ribosomes and RNA
polymerase.
Describe Archaea.
Archaea are prokaryotic and unicellular.
They have call walls made of
polysaccharides, unique plasma
membranes, and ribosomes and RNA
polymerase similar to those of eukaryotes.
Bacteria that cause disease are said to be _______?
pathogenic
What are antibiotics?
molecules that kill bacteria.
Describe what it means to be anoxic.
means lacking oxygen
What is bioremediation?
Bioremediation is the use of bacteria and archaea to
degrade pollutants by (1) fertilizing contaminated sites to
encourage the growth of existing bacteria that degrade
toxic compounds, and (2) adding specific species of
bacteria to contaminated sites.
Extremophiles
bacteria or archaea that live in extreme environments.
Development of an Oxygen Atmosphere.
No free molecular oxygen existed for the first 2.3
billion years of Earth's history
Cyanobacteria
a lineage of photosynthetic bacteria,
were the first organisms to perform oxygenic
(oxygen-producing) photosynthesis.
Many bacteria and archaea must obtain their nitrogen from _______ or _________?
ammonia (NH3) or nitrate (NO3)
How Do Biologists Study Bacteria and Archaea?
•Enrichment cultures are based on establishing a
specific set of growing conditions and are used to isolate
new types of bacteria and archaea (Figure 27.7).
•Direct sequencing is a strategy for documenting the
presence of bacteria and archaea that cannot be grown in
culture and studied in the laboratory (Figure 27.8).
A tree of life based on morphology has only two divisions: ____ and ____
prokaryotes and eukaryotes.
T or F?
The tree of life based on ribosomal RNA
sequences shows three
domains—Archaea, Bacteria, and
Eukarya—and is now accepted as correct.
True!
T or F?
Archaea and Bacteria are more closely related to each other than to Eukarya.
False! •The first lineage to diverge from the common
ancestor of all living organisms was the
Bacteria; the Archaea and Eukarya are more
closely related to each other than to the
Bacteria.
Study table 27.2 in book.
DO IT!
What does gram staining do?
distinguishes bacteria by the type of cell wall.
T or F?
Gram positive cells are pink.
False
T or F?
Gram negative cells are pink.
True
All bacteria and archaea are haploid and
reproduce by _______—the splitting of a cell into
two daughter cells.
Fission
Conjugation tube
forms between cells
that are transferring and receiving a plasmid is a
morphological trait that is unique to bacteria and
archaea.
What happens when conjugation occurs in bacterial cells?
(the act of joining) occurs, a copy of a
plasmid—and potentially one or more genes from
the main bacterial chromosome—moves from one
cell to a recipient cell.
What are plasmids?
extracellular loops of DNA
Bacteria and Archaea produce ATP in how many ways?
3
Describe Phototrophs.
They can use light energy. ATP is
produced by photophosphorylation.
Describe Organotrophs.
They oxidize organic molecules, such as
sugars. ATP is produced by cellular respiration or
fermentation.
Describe Lithotrophs.
They oxidize inorganic molecules, such as
ammonia or methane. ATP is produced by cellular
respiration with the inorganic compound serving as
the electron donor.
What are Autotrophs?
Organisms that manufacture their own carbon-containing compounds.
What are Heterotrophs?
Organisms that acquire carbon-containing compounds by consuming other organisms.
Cellular Respiration: Variation in Electron
Donors and Electron Acceptors
•In cellular respiration, a molecule
with high potential energy serves as
an electron donor and is oxidized,
whereas a molecule with low
potential energy serves as a final
electron acceptor and is reduced.
The potential energy difference is
converted into ATP
What is fermentation?
It is a strategy for making
ATP without using electron transport
chains.
•In fermentation, no electron acceptor is
used; redox reactions are internally
balanced.
What is photosynthesis?
•Through photosynthesis, phototrophs can
use the energy in light to synthesize ATP.
•Photosynthetic bacteria can use many
different wavelengths of light for
photosynthesis.
Some bacteria use the ______ _______to transform carbon dioxide to
organic molecules (same as plants).
Calvin Cycle.
•Other bacteria obtain carbon by
absorbing organic compounds
released in dead tissues.
Describe Methanotrophs
•Methanotrophs use methane as
their primary electron donor and
carbon source. Other bacteria can use
carbon monoxide or methanol.
Describe Spirochaetes (or spirochetes)
• The spirochaetes (or spirochetes) are a phylum of
distinctive bacteria, which have long, helically coiled
cells.
•They are chemoheterotrophic in nature.
•Spirochetes are distinguished by their corkscrew shape
and unusual flagella.
•Important members of this phylum include
–Leptospira species, which causes leptospirosis
–Borrelia burgdorferi, which causes Lyme disease
–Treponema pallidum, which causes syphilis.
•Spirochaetes are gram-negative bacteria
Describe Chlamydiales
• Chlamydiales are spherical and
very tiny.
•They all live as parasites inside
animal cells.
•Chlamydia trachomatis is a common
sexually transmitted disease in
humans that can cause blindness.
Describe High-GC (guanine and cytosine) Grampositive
bacteria
• High-GC (guanine and cytosine) Grampositive
bacteria have various shapes, and
many soil-dwelling species form mycelia
(branched filaments).
•Streptomyces (genus) has many species
that produce antibiotics (steptomycin,
tetracyclin, erythromycin.
•Tuberculosis and leprosy are caused by
members of this group
•Abundant in soil, Streptomyces coelicolor
gives soil its characteristic smell
Describe Cyanobacteria
• Cyanobacteria dominate many marine and
freshwater environments.
•All are photosynthetic
•They produce much of the oxygen and nitrogen,
as well as many organic compounds, that feed
other organisms in freshwater and marine
environments.
•Some are colonial, may form mats or sheets
•Some live in association with fungi, forming
lichens
Low-GC Gram-positive bacteria
• Low-GC Gram-positive bacteria
(Figure 27.20) cause a variety of diseases
including anthrax, botulism, tetanus,
gangrene, and strep throat. Lactobacillus is
used to make yogurt.
Describe Proteobacteria
• The Proteobacteria are a major group of
bacteria. They include a wide variety of
pathogens, such as Escherichia, Salmonella,
Vibrio, Helicobacter, and many other
notable genera.
• Proteobacteria (Figure 27.21) cause
Legionnaire’s disease, cholera, dysentery,
and gonorrhea.
•Certain species can produce vinegars.
•Rhizobium can fix nitrogen.
•All Proteobacteria are gram negative.
Describe Crenarchaeota
• The Crenarchaeota (Figure 27.23)
are the only life-forms present in
certain extreme environments, such
as high-pressure, very hot, very cold,
or very acidic environments.
Describe Euryarchaeota
• The Euryarchaeota (Figure 27.24)
live in every conceivable habitat,
including high-salt, high-pH, and
low-pH environments.
•The Euryarchaeota include the
methanogens, which contribute about
2 billion tons of methane to the
atmosphere each year.