Chapter 27 Bacteria and Arches Flashcards
Cocci
Circle or Spherical prokaryote
Bacill
Rod- shaped prokaryote
Spirochetes
Spiral shaped prokaryote
what are Bacteria Cell Walls made of
Made up of peptidoglycan (sugars+peptides)
what are Eukaryote cell walls made of
made up of chitin
Gram Positive bacteria
have cell walls made up of a thick layer of peptidoglycan
Gram Negative bacteria
has an outer membrane made of lipopolysaccharides (carbohydrates + lipids) with a thin layer of peptidoglycan
Capsule
a dense, sticky layer of polysaccharides that surrounds the cell wall of a prokaryote to prevent dehydration and protect against pathogens
Slime layer
a sticky, thin, unorganized layer that protects cell wall against pathogens and dehydration
Endospore
resistant cells produced by a bacteria cell when exposed to harsh environments
- lack of water or extreme heat. (can survive in temps up to 121)
Fimbriae
hair like appendages of prokaryotes that help attach to substrates or other cells
Fimbriae characteristics
- can survive being boiled in temps to121
- contains no plasmids and little peptidoglycan
- helps cells adhere to human intestines to protect against pathogens
Pili
helps pull cells together
- longer than fimbriae
- less numerous than fimbriae
Taxis
Movement towards or away from a stimuli
Positive taxis
towards
ex: positive phototaxis is movement towards light
Negative taxis
away
ex: negative phototaxis is movement away from light
Flagella
tail like structure used for movement. - can be many all over the cell or can be few on either ends
Parts of Flagella
Motor(rotates tail), Hook(attaches to motor), Filament (tail)
Aerobic prokaryote
Respiratory membrane(infolding of the plasma membrane)
Photosynthetic prokaryote
Thylakoid membrane
How do prokaryotes reproduce?
Binary Fission
Binary Fission
- Duplicate DNA/ chromosomes
- chromosomes attach to one side of the cell wall
- cell lengthens and cell wall forms to split the cell in to two cells.
Importance of mutations in Binary Fission
Rare but when it occurs genetic diversity increases which leads to rapid evolution
Genetice recombination
combining DNA from two different sources
Transformation
Prokaryotic cell is altered by the uptake of DNA from its surrounding
Transduction
phages carrying viruses carry prokaryotic genes from a host cell to another
Conjugation
two prokaryotic cells are temporarily joined and DNA is transferred via membrane. One cell is the receiving cell and one cell gives
F- factor
the ability to form a pili between cells which is used to transfer DNA
F-plasmids
F-factor in plasmids
F+ cells
Donors during conjugation
F- cells
Recipients during conjugation
F-factor in chromosomes
Hfr are donors during conjugation
R Plasmids
bacterial plasmids that carry resistance genes of certain bacteria cells. Can carry up to 10 resistance genes
Phototrophs
organisms that get their energy from light
chemotrophs
organisms that obtain there energy from chemicals
Autotrophs
can make their own food
Heterotrophs
organisms that require on organic nutrient.
- can’t make their own food
Obligate aerobe
Needs O2 for cellular respiration
Obligate anaerobe
poisoned by O2
Facultative anaerobe
Can use O2 if present but not necessary
Nitrogen fixation
process of converting N2 to NH3
Heterocyst
engages in nitrogen fixation
Biofilms
colony of species that engage in metabolic cooperation
Extremophiles
organisms that thrive in extreme environments
Extreme halophiles
organisms that live in extremely salty environments
Extreme thermophiles
organisms that live in extremely hot environments
methanogens
release methane as a by-product
decomposers
break down dead organisms and convert to inorganic forms
cyanobacteria
can make sugars and produce O2
Symbiosis
two different species live together in close contact
Host
provides home and food for a smaller organisms
symbiont
smaller organism living in a host
Commensalism
one species benefits while the other is neither helped nor harmed
parasitism
parasite benefits while the host is harmed
mutualism
both organisms benefit
exotoxins
toxic proteins that are secreted by certain bacteria which causes symptoms even when bacteria is no longer there
endotoxins
toxic component that is releases only when bacteria die and cell walls break down
antibiotic resistance
evolution of bacteria resistance to antibiotics
how do we use bacteria today
- used to convert milk to cheese and yogurt
- modify bacteria to produce vitamins and antibiotics
- used to detoxify and restore polluted ecosytems= bioremediation
