Topic 10: Prokaryotes Flashcards
Prokaryotes
Are small and unicellular cells, lacking a nucleus, with circular genetic material, and membrane-bounded organelles.
What are the 4 Structural and Functional Adaptation?
Cell-surface structures
Metabolically inactive endospores
Motility
Simple Internal organization and DNA
Cell-surface structures
Has a cell wall made that maintains shape, provides protection, and prevents lysing
What is the cell wall difference between Bacteria and Archaea?
Archaea LACKS Peptidoglycan.
Gram Stain
used to differentiate bacteria by cell wall composition.
Gram-positive Bacteria
Have simple thick peptidoglycan layers and retains the violet stain.
Gram-negative Bacteria
Have thin peptidoglycan layers and an outer lipopolysaccharide member; doesn’t retain violet stain.
Metabolically inactive endospores
Endospores are a dormant state that is formed to survive extreme conditions for long periods.
Motility
They posses the ability to move in response to stimuli using flagella.
Capsules
A sticky layer of polysaccharides or proteins that help surfaces stick together and protect against desiccation.
Fimbriae
short, hair-like structures that help cells adhere to surfaces
Pili
Exchange DNA between cells
Simple Internal Organization and DNA
There is no complex compartmentalization, there is only a region for the chromosomes called Nucleoid.
Prokaryote Reproduction
The use asexual, binary fission that results in genetically identical copies of the original cell. It is rapid due to the small cell size.
How do prokaryotes have genetic diversity?
1) Rapid Reproduction
2) Mutations
3) Genetic Recombination
Rapid Reproduction
Through Frequent division many generation occur in a short time
Mutations
Low in binary fission, but the the rapid rate allows for mutation accumulation in a population
Genetic Recombination
Genetic material is exchanged between individual cells.
Horizontal Gene Transfer
Genetic transfer between individuals from different species.
Three Main methods for Genetic Recombination
1) Transformation
2) Transduction
3) Conjugation
1) Transformation
bacteria takes up and integrates DNA from their external environment.
2) Transduction
The transfer of DNA via bacteriophages (viruses)
3) Conjugation
Direct transfer of DNA via a pilus, involving plasmids.
Photoautotrophs
Energy = light
Carbon - Direct CO2 consumption
Chemoautotrophs
Energy = Inorganic chemicals
Carbon = Direct CO2 consumption
Photoheterotroph
Energy = Light
Carbon = organic compounds
Chemoheterophs
Energy = Organic compounds
Carbon = Organic Compounds
Archaea
Are extremophiles; thrive in extreme environments
