Bio 1215-chapter 2
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who came up with the first hierarchical system?
degree of relatedness can be estimated by comparing what four things?
- embryonic or juvenile development
- similarity of sequence of DNA/RNA
- appearance of novel features (ex.milk production)
what are the 3 domains of life?
what are viruses?
microscopic entities that attack living cells
Each particle of a virus is called a _______. Describe this particle.
- nucleic acid in a protein bag
viruses copy by _________ a living cell
what do viruses use to make more virions?
use the host cell's enzymes and raw materials
virion must bond to _______________ of a host cell. Then the viral nucleic acid enters the host.
what 3 things might suggest that viruses are alive?
- have protein
- carry nucleic acid
- use same genetic code as all life
what 2 things suggest that living things are NOT alive?
- no metabolism
- cannot reproduce independently
viruses probably descended from?
how are prokaryotes considered diverse?
diverse in terms of metabolism and habitats
what are the 3 general features of bacteria?
- lack nucleus and membrane-covered organelles
- unicellular but may form clonal colonies or biofilms
what is an example of a prokaryote?
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
Bacteria cell walls contain ____________. Describe it.
- combinations of sugar and peptides
describe gram-positive bacteria.
have many peptidoglycans (purple)
describe gram-negative bacteria.(2)
- have few peptidoglycans (pink)
- have a second outer membrane
what are the 3 bacteria cell shapes?
- spheres (cocci)
- rods (bacilli)
- corkscrews (spirilla)
Many bacteria also secrete an outer, sticky capsule, for what function?
for adhesion and protection
Bacteria cells may have hairlike extensions, for what function?
fasten to host and attach for conjugation.
what are 3 ways bacteria are motile?
- slime gliding
- spinning helical filaments
what is the term used for the movement towards or away from certain stimuli?
what are chemotaxis and phototaxis?
- chemotaxis: movement to and from chemicals
- phototaxis: movement to and from light
Most DNA of bacteria are in one ring-shaped chromosome. They may also contain smaller rings of DNA called?
- replicate independently
- can be transferred/traded between cells
- genes are not essential but may be useful in certain conditions (antibiotic resistance)
Bacteria reproduce via___________ or some produce dormant _______________.
- Binary fission
- resistant endospores
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
what are the 5 main groups of bacteria?
- gram-positive bacteria
Describe 2 things about cyanobacteria.
- capable of fixing nitrogen
Describe 2 things about proteobacteria. Give an example.
- gram-negative eg. salmonella
- includes facultative anaerobes eg. E.Coli
Describe 2 things about chlamydia.
- intracellular animal parasites
- can cause STD and blindness
Describe 2 things about spirochetes.
- corkscrew-like movements,
- eat dead stuff or are parasites
Describe a thing about gram-positive bacteria.
mostly harmless but includes causes of tuberculosis, leprosy, and botulism
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)
what are the difference between thermophiles and halophiles?
- thermophiles: live in hot water
- halophiles : live in very salty water
Prokaryotes "invented" most ________________.
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
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
how can some prokaryotes cause many diseases? (2)
- some through growth and invasion
- some produce toxins
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