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What are prokaryotes?
- -most primitive organism on earth
- - unicellular
- - smallest living organisms (bacteria ) - one tenth the size of eukaryotic cells
- - lack membrane bound organelles
What is the structure of Prokaryotes?
- has ribosomes, DNA, cell wall
why does the ribosomes and DNA have a unique structure?
Ribosomes: chemical composition different, very specific, nucleotides and amino acids different
DNA: haave a single strand of DNA, double helix- 2 ends connected, only 1 DNA molecule on one bacterium
what is the function of cell wall of prokaryotes? compare to cell wall of plants.
offers protection from viruses and maintains cell shape
Cell wall of bacteria: composed of peptidoglycan(small proteins, made of amino acids)
cell wall of plants: has cellulose ( straight strands of sugar, usually parallel )
How do antibiotics selectively destroy bacteria?
1. penicillin: turns off enzyme that makes peptidoglycan- can't grow, divide, cant make cell wall, cell wall becomes too thin and structure breaks POPS!
2. streptomycian: targets ribosomes(suppose to make proteins), shuts off ribosomes so can't make proteins and shuts off
Structure of prokaryotes:
what does the capsule do?
- -slimy polysaccharide or protein coat
- -allows bacterium to attach on to places, can absorb nutrients from cells
what are Fimbriae?
- -numerous, protein containing hair-like projections; allows bacteria to attach to surfaces for nutrients
- ex. intestinal tract
what is flagellum?
stiff, cockscrew shaped protein; attachments that rotate to propel them forwards
what are endospores? example.
consist of a copy of the genetic info surrounded by a thick, protective wall, takes DNA and makes copy, builds coat around it
ex. Bacillus Antracis endospore, used as tactic, most dangerous, inhale and lands in trachea, bacteria produces toxin (millions) and kills you
what is binary fission? explain the steps.
- grows in size and splits- very rapid
- 1. replication of DNA
- 2. separation of DNA
- 3. inward movement of plasma membrane (membrane pinches off)
- 4. new cell wall forms (genetically identical)
whats the difference btwn the copies of the genetic material of prokaryotes to eukaryotes?
Pro: no microtubules
Eu: has microtubules
what is conjugation?
the transfer of a copy of small, circular DMA molecule (plasmid) through a tube like connection (pilus) from one bacterium to another
What is the process of conjugation?
1.donor cell attaches to a recipient cell with its pilus, pilus draws cells together
2. cells contact one another
3. one strand of plasmid DNA transfer to the recipient
4. recipient sythesizes a complementary strand to become an F+ cell; donor sythesizes a complementary strand, restoring its complete plasmid
why conjugation? (benefits)
- -one way transfer
- -release chemicals in environment (communication)
- - when transferred, can code for genetic variation
- -helps with resistance to antibiotics
Classification of Prokaryotes based on SHAPE
- Cocci (coccus)-round
- Bacilli (bacillus)- rod-shaped
- Spirochetes- have flexible cell walls with internal flagella
- Spirilla: have rigid cell walls with external flagella
- Vibrios: comma shaped
Classification of Prokaryotes based on ARRANGEMENT
Diplo- exist in paris
Strepto- exist in chains
Staphylo- exist in clusters or groups
Classification based on STAINING
what color does gram negative stain and why?
Stains pink because of the think cell wall, 2 plasma membranes, (internal and external)
what color does gram-postive stain? why?
staions purple because it has thicker peptodogylcan layer
Why is gram-negative more dangerous than gram-positive?
b/c it has 3 layers of protection
Classification based on METABOLISM
name 3 of them
- 1. heterotropic
- 2. phtoautotropic
- 3. chemoautotropic
What is heterotropic? example.
breakdown organic material of "other" organisms
ex. clostridium botulism, used in botox, produces endosopres
what is photoautotropic? example.
make "own" organic matter using sunlight and in the process, release oxygen; helped with land/diversity of earth
ex. cyanobacteria (blue/green)
what is chemoautotropic? examples.
oxidize inorganic compunds to obtain their energy (only in prokaryotes)
ex. sulfolobales, found near volcanos, in sulfate high environments
Define obligate aerobes, obligate anaerobes and facultative anaerobes
aerobes- survive only in oxygen
anaerobes- can only survive in absence of oxygen
Facultative anaerobes- can survive in presence or absence of oxygen
decomposers of dead organic materials
An organism that lives in or on another organism(its host) and benefits by deriving nutrients at the hosts expense
Diseases caused by prokaryotes
lyme disease, necrotizing fascitis and tetanus
What is lyme disease?
caused by spirochete bacterium carried by ticks
symptoms: red rash, red circles
what is necrotizing fascitis?
-flesh eating disease, caused by streptococcal bacterium, spread in soils, toxin dissolves tissues and muscles
what is tetanus?
- caused by obligate anaerobic bacillus bacterium and thrives in deep wounds
symptoms: spazams, lock jaw, permanant muscle contractions
Symbiotic relationships with prokaryotes
what are the 2 ?
nitrogen fixation and bioluminescent
what is nitrogen fixation?
carried out by backteria in root nodules - convert N2 (nitrogen) in atmosphere to NH3 (ammonia)
where do prokaryotes breakdown the cellulose of plant cell walls?
in the digestive tract of herbivores
* plants produce enzyme called cellulase that break down cellulose into glucose
whats the role of bacteria in our digestive tract?
take waste in colon and make it useful, vitamin K for blood clotting and vitamin B12 - important for RBC's to be mature, produces more surface area so can squeeze through capillaries
what are bioluminescent prokaryotes? purpose?
- live within organs in deep sea marine life, production and emission of light by a living organism,
- - purpose is to attract mates and distract enemies
importance of prokaryotes
saprophytic bacteria are used in biomediation. how?
when they use micro-organisms to clean up pollutants in environment (natural way)
ex. oil spills
what is the ecological importance of saprophytic?
decompose soil, encouraging them to grow, decomposing organic material
why do bacteria produce antibiotics?
for protection, to get rid of competition
bacteria can convert milk sugar(lactose) to .....? and for what?
to lactic acid to produe the sour flavor of yogurt and pickles, and the flavours of any cheeses
use of prokaryotes in biological engineering.
what is it?
humans can now modify bacteria to prduce vitamins, antibiotics, hormones and other products
what is the process of biological engineering?
- 1.desired gene(codes for protein) is inserted into a plasmid
- 2. plasmid(circular strand of DNA) is inserted into a bacterium
- 3. bacterium divides and makes muliple copies of the gene
- 4. gene can be inserted into plants to make them resistant to spoilage and disease
- - can also be used to alter bacteria for cleaning toxic wastes
- - or can be expressed to produce a protein for the treatment of disease ex. dwafism: give growth hormones
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