Shapes of Prokaryotes
Coccus- spherical
Bacillus- rod shaped
Spirillum- spiral
Cell wall
contain peptidoglycan
Archaea polysaccharides and proteins do not have peptidoglycan
Capsule
secreted outside the cell wall; sometimes causes cells to stick to each other and also to other surfaces
Fimbriae
surface appendages help stick to surfaces and to each other
Pili
longer than fimbriae; aids in DNA transfer
Flagella
in some bacteria, provides motility
prokaryote DNA
most have one ring shaped chromosomes. many contain additional plasmids
plasmids
smaller rings of DNA; may also aid in resistance to antibiotics and other processes
binary fission
mostly asexual reproduction
transformation
prokaryotic cell takes up genes from surrounding environment, even between different species (horizontal gene transfer)
conjugation
direct transfer from one to another, connect by special pilus; forms cytoplasmic bridge
transduction
viruses transfer from one prokaryote to another
genetic variation due to:
rapid reproduction, mutations, and genetic recombination
mutation
major source for genetic variation
endospores
resistant cells that form hard shells around the chromosome, and the outer shell disintegrates, may remain dormant for years.
Chemoheterotrophs
traditional bacteria
photoautotrophs
cyanobacteria
saprobes
absorb nutirents
parasites
have living hosts
obligate anaerobes
oxygen is toxic
facilatative anaerobes
can respire with or without oxygen
cyanobacteria
traditionally known as blue green algae, many red in color, first photosynthetic organisms on Earth, supplied first oxygen to atmosphere, built up ozone layer
akinetes
similar to endospores
heterocysts
specialized cells capable of nitrogen fixation
gelatinous sheath
outer covering; sticky; keeps in moisture
Domain archaea
share certain traits with bacteria, and others with eurkaryotes, fewer in number than bacteria, found in extreme environments
Halophiles
salt loving
thermophiles
heat loving
bacteria importances
disease causing, symbiotic, decomposers, bioremdiation, antibiotics
Cyanobacteria importances
early oxygen, producers of food chain, some produce toxins, nitrogen fixation, symbiotic
pathogenic facter
prokaryotes cause about half of all human diseases
prokaryotes include
bacteria and archaea
some bacteria have surface appendages such as ________, which help stick to surfaces and to each other
fimbriae
the major source of variation in the prokaryotes is
mutation
True/False: cyanobacteria are considered autotrophs because they can photosynthesize
true
special cells of the cyanobacteria which are capable of nitrogen fixation are called
heterocysts
the term ______________ is used for bacteria involved in chemical or oil clean up
bioremediation
which of the following is not an importance of the prokaryotes?
A. bioremediation
B. disease causing
C. nitrogen fixation
D. cause red tides
D
Archaea which are found in extreme salty environments are called ___________
halophiles
prokaryotes can exchange genetic material with other prokaryotes by direct transfer using pili. This process is called:
A. transformation
B. binary fission
C. conjugation
D. transduction
C
bacteria can resist harsh environmental conditions by forming resistant
endospores