CHAPTER 11 Flashcards
Three basic shapes of prokaryotic cells are
spherical cocci, rod-shaped bacilli, and spirals.
spirals may be
stiff (spirilla)
flexible (spirochetes)
Other variations in shapes include
vibrios (slightly curved)
coccobcilli (intermediate to cocci and bacilli)
pleomorpnhic (variable shape and size)
produced within vegetative cells of the Gram-positive genera Bacillus and Clostridium.
environmentally resistant endospores
kinds of endospores
terminal
subterminal
centrally located
Prokaryotes reproduce asexually by
binary fission, snapping division (a type of binary fission), spore formation, and budding.
Cocci may typically be found in groups, including
long chains (streptococci), pairs (diplococci), four- somes (tetrads), cuboidal packets (sarcinae), and clusters (staphylococci).
three domains of living things
archaea
bacteria
eukarya
how many phylas of archaea are there
5
how many phylas of bacteria are there
24
part of domain archaea ; microbes that require extreme conditions of temperature, pH, pressure, and/or salinity to survive.
extremophiles
live at temperatures above 45°C and 80°C, respectively, because their DNA, membranes, and proteins do not function properly at lower temperatures.
Thermopiles and hyperthermophiles
depend on high concen- trations of salt to keep their cell walls intact. Halophiles such as Halobacterium salinarum
Halophiles
Halophiles such as Halobacterium salinarum synthesize purple proteins called __ that harvest light energy to synthesize ATP.
Bacteriorhodopsins
are obligate anaerobes that produce methane gas and are useful in sewage treatment.
Methanogens
have rRNA sequences thought to be similar to those of earliest bacteria. They are autotrophic and live in hot, acidic, and anaerobic environments, often with intense exposure to sun.
Deeply branching bacteria
trap light energy with photosynthetic lamellae.
Photographic bacteria
The five groups of phototrophic bacteria are
cyanobacte- ria, green sulfur bacteria, green nonsulfur bacteria, purple sulfur bacteria, and purple nonsulfur bacteria
reduce atmospheric N2 to NH3 via a process called nitrogen fixation
Cyanobacteria
Many cyanobacteria fix nitrogen in thick-walled cells called
Heterocysts
Green and purple bacteria use ___ for anoxygenic photosynthesis.
bacteriochlorophylls
contains bacteria with a G + C content (the percentage of all base pairs that are guanine-cytosine base pairs) of less than 50%.
Firmicutes
include the genus Clostridium (pathogenic bacteria that cause gangrene, tetanus, botulism, and diarrhea), Epulopiscium (which is large enough to be seen without a microscope), and Selenomonas (often found in dental plaque
Clostridia
are Gram-positive, pleomorphic, facultative anaer- obes and obligate anaerobes that lack cell walls and therefore stain pink with Gram stain. They are frequently associated with pneumonia and urinary tract infections.
Mycoplasma
Examples of low G + C gram positive bacilli and cocci important to human health and industry
Bacillus
staphylococcus
Listeria
lactobacillus
Streptococcus
enterococcus
high G + C bram-positive bacteria are classified in
Phylum actinobacteria
Bacteria in Corynebacterium store phosphates in
Metachromatic granules
Members of the genus Mycobacterium, including species that cause tuberculosis and leprosy, grow slowly and have unique, resistant cell walls containing waxy
mycolic acids
resemble fungi in that they produce spores and form filaments; this group includes Actinomyces (normally found in human mouths), Nocardia (useful in degradation of pollutants), and Streptomyces (produces important antibiotics).
Actinomycetes
a very large group of Gram-negative bacteria divided into five classes—the alpha-, beta-, gamma-, delta-, and epsilonproteobacteria.
Proteobacteria
include a variety of aerobes, many
of which have unusual cellular extensions called prosthecae. Azospirillum and Rhizobium are nitrogen fixers that are important in agriculture.
Alphaproteobacteria
Some members of the alphaproteobacteria are nitrifying bacteria, which oxidize NH3 to NO3 via a process called
Nitrification
include the nitrifying Nitrosomonas
and pathogenic species such as Neisseria (gonorrhea), Bordetella (whooping cough), and Burkholderia (which colonizes the lungs of cystic fibrosis patients).
Beta proteobacteria
constitute the largest class of proteobacteria; they include purple sulfur bacteria, intracel- lular pathogens, methane oxidizers, facultative anaerobes that utilize glycolysis and the pentose phosphate pathway, and pseudomonads.
Gamma proteobacteria
are anaerobic bacteria that use methane for both carbon and energy.
Methane oxidizers
including pathogenic Pseudomonas and nitrogen- fixing Azotobacter and Azomonas, utilize the Entner-Doudoroff and pentose phosphate pathways for catabolism of glucose.
Pseudomonads
include Desulfovibrio (important in the sulfur cycle and in corrosion of pipes), Bdellovibrio (pathogenic to bacteria), and myxobacteria. The latter form stalked fruiting bod- ies containing resistant, dormant myxospores.
Delta proteobacteria
include some important human patho-
gens, including Campylobacter and Helicobacter.
Epsilon proteobacteria
Scientists discovered ___ using metagenomic sequencing, which entails sequencing all the DNA from a site so as to ascertain all microbes present. Zetaproteobacteria oxidize iron in marine environments.
zetaproteobacteria
are Gram-negative cocci typified by the genus Chlamydia; they cause neonatal blindness, pneumonia, and a sexually transmitted disease.
Chlamydias
flexible, helical bacteria that live in diverse envi- ronments. The pathogens Treponema (syphilis) and Borrelia (Lyme disease) are important spirochetes.
Spirochetes
flexible, helical bacteria that live in diverse envi- ronments. The pathogens Treponema (syphilis) and Borrelia (Lyme disease) are important spirochetes.
Spirochetes
include Bacteroides, an obligate anaerobic rod
that inhabits the digestive tract, and Cytophaga, an aerobic rod that degrades wood and raw sewage.
Bacteroids
types of proteobacteria
alpha
beta
gamma
delta
epsilon
zeta
used to describe cells that are intermediate in shape between cocci and bacilli; that is, it is difficult to ascertain whether a coccobacillus is an elongated coccus or a short bacillus.
Coccobacillus
A variation of binary fission called
Snapping division
survey of archaea
extremophiles
methanogens
two kinds of extremophiles
halophiles and thermophiles
survey of bacteria
deeply branching and phototrophic bacteira
survey of bacteria
deeply branching and phototrophic bacteria
low g + c gram positive bacteria
high g + c gram posiitve
gram negative proteobacteria
other gram negative
types of firmicutes
clostridia
mollicutes
bacilli
what are the other gram negative bacteria
chlamydias
spirochetes
bacteroids
