Bio ch 25
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Bio ch 25
bio ch 25
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
and have fewer protiens and RNA molecules
what does prokayotes cytoplasm made 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?
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
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 CO
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 CO
Use e- they remove in oxidations to make organic molecules by reducing CO
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 CO
What are Photoheterotrophs?
Use light as ultimate energy source
Obtain carbon in organic form other then CO
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 (NH
Only process for replenishing nitrogen sources used by plants and animals
What is Nitrification?
The conversion of ammonium (NH
+) to nitrite(NO
-) 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?
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
ex. treponema pallidum which causes syphilis
Name some features of Chlamydias
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
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
Some extreme thermophiles
List some characteristics of Methanogens
Represent about half of all known species of Archaens
live in reducing environment
List some characterisitcs of Halophiles
All belong to Euryarchaeota
need min. conctration of 1.5M NaCl to live
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