Can be distinguished by the shape of their cells, and the colonies they form ∙ Spirochete (spiral) ∙ Bacillus (rodshape)
Capsule
a sticky layer that surrounds the cell walls of some prokaryotes, protecting the cell surface and sometimes helping to glue the cell to surfaces.
Cell wall
a protective layer external to the plasma membrane in plant cells, prokaryotes, fungi, and some protists.
Plasma membrane
the membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell’s chemical composition
Pili
a long, hairlike prokaryotic appendage that functions in adherence or in the transfer of DNA during conjugation; help bacteria adhere
Plasmid
a small ring of DNA that carries accessory genes separate from those of bacterial chromosome; also found in some eukaryotes, such as yeast
Ribosomes
a cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.
Bacterial flagellum
taillike structure; enable bacteria to move; evolved independently of eukaryotic flagella.
Nucleoid (circular DNA)
a dense region of DNA in a prokaryotic cell. Prokaryotic, unicellular, various nutritional modes
Cell walls made of peptidoglycan
Bacterial chromosome is a single circular piece of DNA
Have small extrachromosomal DNA segments called plasmids
Some bacteria have a capsule outside their cell wall making them more pathogenic.
Bacterial cell membrane is the major organelle used for bacterial metabolism
Bacteria have evolved all major forms of metabolism.
Bacterial ribosomes are smaller than eukaryotic ribosomes, which makes them a good target for antibiotics. Binary fission: bacterial reproduction
∙ The cell copies the chromosomes and splits in half.
∙ Asexual, and can happen very fast
∙ 1 bacterium can reproduce every 20 minutes
Þ cell (chromosomal)à DNA replicationàsegregationà cytokinesis
what creates antibiotics resistance and why they are affected?
∙ Antibiotic penicillin mold, the thing that kills bacteria isolate that protein to kill it;
∙ Antibiotics kill bacteria by interrupting cell wall synthesis or interfering with vital processes like protein synthesis, all while leaving human cells unharmed.
∙ Ampicillin resistance can kill bacteria and the bacteria can’t fight.
∙ Individual bacteria can undergo random mutations, which can help bacteria from being killed by antibiotics; natural selection. Vocab
horizontal transfer exchange of genetic information between bacterial cell; increases and spreads genetic diversity.
∙ Examples of “recombination” of DNA from 2 sources
Transformation bacteria take in plasmids from the environment
Conjugation bacteria exchange DNA through a direct connection
Transduction bacteria acquire new DNA from a phage (bacterial virus) Viruses: DNA vs. RNA
Viruses consists of : gene information and a protein coat (capsid)
Are not traditionally considered to be alive because they can not carry out their life cycle independent of a host cell.
Prokaryotic viruses:
∙ Known as PHAGES: virulent phages and temperate phages
∙ Virulent phages: “classic” viral life cycle
Infection, synthesis, assembly release
Assembly is autocatalytic
∙ Temperate phages: “the lysogenic” cycle
Phage DNA splices in to bacterial chromosome.
When cell replicates, phage DNA is replicated, too.
