Module 3: Structure And Biology Of Prokaryotes Flashcards
What are exotoxins?
Exotoxins are usually proteins and are secreted.
They are among the most potent poisons known.
What are endotoxins?
Endotoxins are components of outer cell membranes and cells walls of bacteria.
They trigger the immune response: causing fevers and aches.
What is an endospore?
A dormant dehydrated structure formed by bacteria.
How is an endospore formed?
Certain gram-positive bacteria undergo unequal cell division and produce the highly stable dormant endospore. The bacterium then disintegrates, releasing the spore.
When is an endospore formed?
Endospores are formed in adverse conditions. E.g. unsustainable temperatures, pH or salinity.
How do endospores survive?
Endospores are resistant to heat, cold and lack of nutrients.
They can remain viable and dormant for many years.
Antiseptic methods of sterilisation cannot kill endospores.
What are the domains of life?
Bacteria,
Archaea,
Eukarya
How can bacteria be indentified?
- Observing shape and size under a microscope.
- Differential structure, e.g. gram staining.
- Metabolism - anaerobic or aerobic.
- Nutrient requirements.
- Chemical assays that detect unique molecular structures.
What is the process of binary fission?
- Genome (chromsome) is replicated.
- As the cell grows, the two chromosomes separate to opposite ends of the cell.
- When the chromosomes are completely separate, the cytoplasm splits the cell into two.
- There are now two daughter cells that are identical to the original cell.
How are scientific names written?
Genus species
Or, if written, the words are underlined. Capitalisation of the Species and lowercase of the genus is important.
What are the prokaryotic domains?
Bacteria,
Archaea
What are the eukaryotes domains?
Eukarya
What is an antibiotic?
Any substance produced by an organism that is antagonistic to the growth of prokaryotes.
The lipopolysaccharide layer (LPS) is characteristic of…?
Gram-negative bacterial cell walls.
