Bio ch 25
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What are the 3 common shapes of prokaryotes?
what shape does cocci mean?
what shape does bacilli mean?
what shape does Spirilla mean?
What are plasmids?
contain genes with functions that supplement those in nucleoid
what is the internal structure of prokaryotes?
- small circles of DNA called plasmids
- Ribosomes that are smaller than eukaroytes
- and have fewer protiens and RNA molecules
what does prokayotes cytoplasm made of?
- granules of:
What is the primary structural molecule of bacteria cell wall?
what is peptidoglycan?
a polymer formed from a polysaccharide backbone with polypeptides
What are the steps of the Gram stain technique?
- Treat bacteria with crystal violet dye, then iodine
- bacteria then washed with ethanol, then with fushin or sfranin
If a bacteria tests gram positive it means?
the cell wall consists of a thick peptide layer and will be stained purple
If a bacteria is Gram negative it means?
that the cell has a thin peptide layer and will be stained pink
Concerning prokaryotic cell walls, the outermembrane covers what layer?
What consists of the outer membrane? What does it do?
- consists of lipopolysaccharides
- and protects Gram Negative bacteria
walls of Gram positive and Gram negative bacteria are coated with an external layer of...?
what is Glycocolyx?
- 2 forms
- The "slime layer" when it's diffuse and lossely associated with the cells
"Capsule" when it's gelatinous and more firmly attached to the cells
What is the most common mechanism for movement in bacteria and archaens to allow them to move through liquids and wet surfaces?
What aspect of the flagella differs from tht of eykaryotes and prokaryotes
- Eukaryotes have micotubles in flagella
- Prokaryotes have no micotubles
What is Pili? What is it used for?
- Rigid, hairlike shfts of a
- protein = pili
Maybe be used for sexual reproduction I.E. genetic transfer
Do Prokaryotes have the greatest metabolic diversity of all living organisms?
What is an Autotroph?
Obtain carbon from CO2
What is a Heterotroph?
Obtain carbon from organic molecules of living hosts, or from products, wastes, or dead organisms
What is a Chemoautotroph?
- Obtain energy from inorgainc substances
- ex. H, Fe, S, Nitrites
- Obtain carbon from CO2
- Use e- they remove in oxidations to make organic molecules by reducing CO2 or provide energy for ATP synthesis
What are Chemoheterotrophs?
- Oxidize organic molecules as their energy source
- Obtain carbon in organic form
What are Photoautotrophs?
- Photosynthetic (light as energy source)
- Carbon from CO2
What are Photoheterotrophs?
- Use light as ultimate energy source
- Obtain carbon in organic form other then CO2
What are Aerobes?
Require oxygen for cellular respiration (oxygen is final electron acceptor)
What is an obligate aerobe?
Cannot grow without oxygen
What is an anarobe?
Do not require oxygen to live
What is an obligate anarobe?
- Poisoned by oxygen
- survive by fermenting in which organic molecules are final e- acceptor
What are facultive anarobes?
- Use oxygen when it's present
- Under anaerobic conditions they live by fermentation
What is Nitrogen fixation?
- Process in which atmospheric nitrogen to ammonia (NH3 )
- Only process for replenishing nitrogen sources used by plants and animals
What is Nitrification?
The conversion of ammonium (NH4
+) to nitrite(NO2
-) which is carried out in 2 steps
- 1 type converts ammoium to nitrite
- Other type converts nitrite to nitrate
- Both are usually present in soils and water
What is the normal mode of reproduction in prokaryotes?
What is binary fission?
during asexual reproduction the parent cell divides into 2 daughter cells that are exact genetic copies of the parent
What is conjugation?
during sexual reproduction, exchange genetic material when 2 parent cells join or mate
What does Biofilm consist of?
A complex aggregation of microorganisms attached to a surace
What are the 5 major evolutionary groups of Bacteria?
- Gram-positive bacteria
Name some features of Proteobacteria
- Highly diverse group
- largest of all groups
- ex. myxobacteria which has a fruiting body
Name some features of Spirochetes
- Gram negative bacteria
- Helically or spiralled bodies
- linear chromosomes
- ex. treponema pallidum which causes syphilis
Name some features of Chlamydias
- Gram-Negative bacteria
- Have cell walls with a membrane outside of them
- Are Obligate intracellular parasites=only reproduce within other cells
- Causes various diseases within animals
- Ex. trachomatis = urinary tract infection
Name some features of Gram-Positive Bacteria
- Gram Positive
- live primarily as chemoheterotrophs
- Thick cell walls
- Some are beneficial to humans
- ex. lactobacillus cary out lactic acid fermentation used in production of pickles
Name some features of Cyanobacteria
- Live and photoautotrophs
- Have chlorophyll = their pigment
- use same pathway for phtosynthetic plants and algae
- Release oxygen as a byproduct of photosynthesis
What are exotoxins?
Toxic proteins that are secreted from the bacterium
what are endotoxins?
Toxic protenins secreted from bacteria after they have died
What are Exoenzymes?
Enzymatic proteins that digest plasma membranes and cause cells of infected host to rupture and die
Name some basic features of the domain Archaea
- Found in estrmem environments such as hot springs, thermal vents, and salt lakes
- many are chemoautotrophs
- many are chemoheterotrophs
What are the 3 evolutionary branches in the archaea
What are the 3 found in Euryarchaeota
- Extreme Halophiles
- Some extreme thermophiles
List some characteristics of Methanogens
- Represent about half of all known species of Archaens
- obligate anaerobes
- live in reducing environment
List some characterisitcs of Halophiles
- Salt loving
- All belong to Euryarchaeota
- need min. conctration of 1.5M NaCl to live
- aerobic chemoheterotrophs
List some characteristics of Extreme thermophiles
Need environment of 70-95 Celsius for maximum growth
List features of Crenarchaeota
- Contains most of the extreme thermophiles
- temp range 75-105
- Psychrophiles = cold loving
- grow optimally in range of -10 to -20
List some things about Korchaeota
- recognized by analyzing rRNA sequences in DNA from marine and terrestrial environments= hydrothermal
- Oldest lineage in domain Archaea
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