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CanuckGirl
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who came up with the first hierarchical system?
Linnaeus
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degree of relatedness can be estimated by comparing what four things?
- anatomy
- embryonic or juvenile development
- similarity of sequence of DNA/RNA
- appearance of novel features (ex.milk production)
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what are the 3 domains of life?
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what are viruses?
microscopic entities that attack living cells
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Each particle of a virus is called a _______. Describe this particle.
- virion
- nucleic acid in a protein bag
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viruses copy by _________ a living cell
hijacking
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what do viruses use to make more virions?
use the host cell's enzymes and raw materials
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virion must bond to _______________ of a host cell. Then the viral nucleic acid enters the host.
surface protein
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what 3 things might suggest that viruses are alive?
- have protein
- carry nucleic acid
- use same genetic code as all life
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what 2 things suggest that living things are NOT alive?
- no metabolism
- cannot reproduce independently
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viruses probably descended from?
escaped genes
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how are prokaryotes considered diverse?
diverse in terms of metabolism and habitats
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what are the 3 general features of bacteria?
- lack nucleus and membrane-covered organelles
- unicellular
but may form clonal colonies or biofilms
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what is an example of a prokaryote?
bacteria
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what is the advantage of bacteria having lots of membrane?
more membrane means there is more surface area to undergo reactions such as photosynthesis and cellular respiration
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Bacteria cell walls contain ____________. Describe it.
- peptidoglycans
- combinations of sugar and peptides
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describe gram-positive bacteria.
have many peptidoglycans (purple)
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describe gram-negative bacteria.(2)
- have few peptidoglycans (pink)
- have a second outer membrane
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what are the 3 bacteria cell shapes?
- spheres (cocci)
- rods (bacilli)
- corkscrews (spirilla)
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Many bacteria also secrete an outer, sticky capsule, for what function?
for adhesion and protection
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Bacteria cells may have hairlike extensions, for what function?
fasten to host and attach for conjugation.
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what are 3 ways bacteria are motile?
- flagella
- slime gliding
- spinning helical filaments
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what is the term used for the movement towards or away from certain stimuli?
taxis
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what are chemotaxis and phototaxis?
- chemotaxis: movement to and from chemicals
- phototaxis: movement to and from light
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Most DNA of bacteria are in one ring-shaped chromosome. They may also contain smaller rings of DNA called?
plasmids
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Describe plasmids.(3)
- replicate independently
- can be transferred/traded between cells
- genes are not essential but may be useful in certain conditions (antibiotic resistance)
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Bacteria reproduce via___________ or some produce dormant _______________.
- Binary fission
- resistant endospores
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what are the 3 ways that bacteria reproduce?
- transformation: taking in external DNA from the surroundings
- conjugation: a direct transfer of DNA from once cell to another
- transduction: accidental transfer by viruses
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what are the 5 main groups of bacteria?
- cyanobacteria
- proteobacteria
- chlamydia
- spirochetes
- gram-positive bacteria
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Describe 2 things about cyanobacteria.
- photosynthetic
- capable of fixing nitrogen
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Describe 2 things about proteobacteria. Give an example.
- gram-negative eg. salmonella
- includes facultative anaerobes eg. E.Coli
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Describe 2 things about chlamydia.
- intracellular animal parasites
- can cause STD and blindness
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Describe 2 things about spirochetes.
- corkscrew-like movements,
- eat dead stuff or are parasites
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Describe a thing about gram-positive bacteria.
mostly harmless but includes causes of tuberculosis, leprosy, and botulism
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Describe 4 things about archaea.
- look like bacteria but are closely related to eukaryotes
- no peptidoglycans in cell wall
- unique lipids in membrane
- many live in anaerobic or extreme environments (extremophiles)
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what are the difference between thermophiles and halophiles?
- thermophiles: live in hot water
- halophiles : live in very salty water
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Prokaryotes "invented" most ________________.
metabolic pathways
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what are 5 things that show the "importance" of prokaryotes?
- cycle of chemicals
- many symbiotic relationships with other species
- some of the toxins produced by some species are used for antibiotics
- genetically-engineered bacteria used to produce insulin + other drugs
- help produce yogurt and cheese
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what is an example of how prokaryotes cycle chemicals? what are they useful for?
- photosynthetic cyanobacteria that 'fix" carbon (construct organic molecules from CO2); only nitrogen fixers
- useful for sewage plants; oil spill clean ups
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how can some prokaryotes cause many diseases? (2)
- some through growth and invasion
- some produce toxins
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