Microbiology
Are viruses living?
In my opinion viruses are non-living. Viruses have the ability to be completely dehydrated, require a host cell, and have no organelles. These points clearly confirm that viruses are unlike any living thing on Earth. Viruses don't contain the 'machinery' for reproduction and must find a host cell, making viruses parasitic. However, our classification of living things is artificial which makes room for error. Viruses in my opinion are still non-living, the crucial turning point for me is that they need a host cell to survive.
Form and arrangement of bacteria
3. Spirillum
Form: long and curved Arrangement: usually found in single arrangements |
How do bacteria obtain carbon and energy?
Energy:
1. Phototrophic-bacteria that use light energy
2. Chemotrophic-uses chemicals, either from a C based source or a non-C based source
Carbon: bacteria are either a heterotroph or an autotroph
1. Autotrophic: requires an inorganic C source, CO2
2. Heterotrophic: Requires an organic C source like glucose (C6H12O6)
1. Autotrophic: bacteria that make their own food
a) Photoautotroph-use light energy with CO2 to make organic compounds
e.g. cyanobacteria
b) Chemoautotroph-use CO2 and energy from inorganic molecules
e.g. nitrogen fixing bacteria using NH3
2. Heterotrophic: requires an organic C source
a) Photoheterotroph- uses light and an organic food source to make ATP; very few prokaryotes do this
e.g. purple non-sulphur bacteria
b) Chemoheterotroph-consume organic C sources for carbon and energy; most commonly used method
e.g. salmonella
1. Phototrophic-bacteria that use light energy
2. Chemotrophic-uses chemicals, either from a C based source or a non-C based source
Carbon: bacteria are either a heterotroph or an autotroph
1. Autotrophic: requires an inorganic C source, CO2
2. Heterotrophic: Requires an organic C source like glucose (C6H12O6)
1. Autotrophic: bacteria that make their own food
a) Photoautotroph-use light energy with CO2 to make organic compounds
e.g. cyanobacteria
b) Chemoautotroph-use CO2 and energy from inorganic molecules
e.g. nitrogen fixing bacteria using NH3
2. Heterotrophic: requires an organic C source
a) Photoheterotroph- uses light and an organic food source to make ATP; very few prokaryotes do this
e.g. purple non-sulphur bacteria
b) Chemoheterotroph-consume organic C sources for carbon and energy; most commonly used method
e.g. salmonella
How bacterial reproduction, antibiotic resistance, and evolution are all related
Since antibiotics are so excessively used, bacteria have been able to evolve to resist the effects of antibiotics. This is an example of directional selection, with the desirable extreme being antibiotic resistance. Bacterial reproduction will occur, allowing the gene for antibiotic resistance to pass down to the next generation. As more bacteria are overexposed to antibiotics, the next generation of bacteria will be so well refined they may not be so easy to get rid of.
What is the purpose of gram staining and what can we learn from it?
The purpose of a gram stain is to determine if bacteria are present and also to allow bacteria to be viewed under a microscope. We can determine if bacteria are gram positive or gram negative which is helpful in curing bacterial infections. We can also learn bacterial form and arrangement bacteria using gram staining.