Prokaryotes Flashcards
What are the key features of a prokaryote?
- Has all the common features of ALL cells
- Has DNA in a singular continuous loop
- Many have extra-cellular DNA (plasmids, capsules, fimbriae)
- NO nucleus
- NO membrane-enclosed organelles
What is metabolic cooperation?
The exchange of molecules between cells through direct cell-to-cell contact which allows them to use environmental resources they could not use as individual cells
What 4 characteristics enabled prokaryotes to reach huge population sizes and thrive in diverse environments?
- Small size
- Rapid reproduction
- Mutations produce high genetic diversity –> rapid evolution
- diverse adaptations to live in a wide range of environment
What are the 2 ways that prokaryotes attach to structures?
Fimbriae and capsules
How are prokaryotes motile?
Flagella/flagellum embedded in both the cell membrane and cell walls.
How do prokaryote cells reproduce?
Binary fission
What is binary fission?
A type of asexual reproduction where a single-celled organism divides into two identical daughter cells (exact copies of the parent cell)
What are the 3 main prokaryote reproductive structures?
- Nucleoid
- A main circular chromosome
- Has plasmids
What are the 3 ways that bacteria can share DNA (i.e. horizontal gene transfer)?
- Conjugation
- Transformation
- Transduction
What is conjugation?
The process where genetic material is transferred between 2 prokaryote cells (usually of the same species) that are temporarily joined
What is transformation?
The development of new genetic traits in a cell after taking in foreign DNA from the environment
What is transduction?
A process in which viruses carry bacterial DNA from one bacteria to another.
What is Nitrogen Fixation?
The conversion of atmospheric nitrogen to ammonia that only occurs in the absence of oxygen.
What is mutualistic bacteria?
Bacteria that benefit from a relationship with another species, and that relationship also benefits the other species (e.g. human intestines)
How are pathogenic bacteria symptoms induced by?
- direct parasitic effects (e.g. destruction of tissue)
- toxins (exo/endotoxins)
- food poisoning
- bacterial diseases
What are antibiotics?
Produced naturally by microbes to reduce competition for resources.
How do bacteria support the biosphere?
Chemical recycling (decomposing, increasing/decreasing the availability of nutrients, global nitrogen cycle)
What is pathogenic bacteria?
Bacteria that cause illness usually with toxins (exo-/endo toxins)
What are exotoxins?
Proteins secreted by certain bacteria and other organisms
What are endotoxins?
Toxins release when the bacteria die and their cell walls break down.
What are some beneficial uses of bacteria for humans?
- used in the production of milk, cheese, beer, wine
- modified bacteria to produce vitamins, antibiotics, hormones
- Some bacteria can be used to produce a natural plastic
What are the key structures of bacteria?
- cell membrane
- DNA material in a nucleoid
- Sits within the cytoplasm
What are the 3 main unicellular shapes of bacteria cells?
- cocci
- bacilli
- spiral
What is a key role of Archaea in the environment?
To release methane as a by-product of how they obtain energy.
