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Prokaryotes and eukaryotes 1 lack

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Unformatted text preview: es and eukaryotes (1) Lack compartmentalization by internal membranes nothing inside cells (2) Many have infolded regions of the plasma membrane increase surface area for chemical reactions to take place (invagination) (3) Smaller simpler genomes ~1/1000 as much DNA double-stranded circular DNA nucliod single, circular DNA have smaller rings of DNA - plasmids needed for special contingencies genes for antibiotic resistance replicate independently metabolize organic material-some sort of sugar? can be transferred between partners take bacteria-place into plasmids-able to transfer (4) Ribosomes smaller & differ in protein content can be selectively targeted because they differ expressing proteins-assembled on ribosome Certain antibiotics such as erythromycin and bind to prokaryotic ribosomes and block protein synthesis. Reproduction Reproduce asexually by binary fission no mitosis or meiosis grows and splits in half NOT ACTUAL SIZE Growth- refers to increase in population size With unlimited resources growth is geometric Generation times:1-3 hours; some double every 20 min. Can reach incredible densities - 100x109/ mL in human colon VERY successful because of diversity Mutation is major source of genetic variation Short generation times and large populations - favorable mutation can propagate rapidly depends of mutation rates Very rapid adaptation to environmental change Horizontal Gene Transfer - Bringing together DNA from different individuals transfer between different prokaryotes - facilitates rapid evolution Prokaryotes have 3 mechanisms that can function to transfer genes between individuals. (1) Transformation - cell takes up genes from surrounding environment (one strain transformed into another) relationship between DNA and genetic material; showed strep bacteria- one dead and one alive; can transfer the dead one to alive one and picks up bacteria (2) Conjugation - direct transfer of genes from one prokaryote to another usually between same species (3) Transduction - viruses transfer genes from one prokaryote to another viruses that affect only bacteria - bacteria fages? virus transfer via one bacteria to another Prokaryotes can withstand harsh conditions Some form resistant cells – endospores, when essential nutrient in environment is lacking. Endospores can withstand boiling water and can everything dies but endospore and can stay in remain dormant for centuries. condition for hund...
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