Week 3 - Intro to Microbiology and Bacteria Flashcards
What are the types of Microbes
- Bacteria
- Viruses
- Parasites
- Fungi
- Prions
What’s the difference between Prokaryotes and Eukaryotes
- Prokaryotes are always unicellular while eukaryotes are often multi-celled organisms.
- Eukaryotes are more complex and larger cells than prokaryotic cells
- DNA in eukaryotes is stored within a nucleus while DNA is just floating freely in the cytoplasm of prokaryote cells
What is bacteria
Bacteria are small prokaryotic organisms that are found in every habitat on earth
Example of bacteria
E. Coli
Strep mutans
What are the main characteristics of bacteria
- capsules
- endospores
What is this structure and its function
Flagellum
Acts like a tail and propels the bacteria through substances
What is this structure and its function
Capsule
- Serves as a shield which protects the cell from physical evade the host immune system.
- The ‘stickiness’ of the capsule promotes cell adhesion to surfaces, a survival advantage.
What is this structure and its function
Cell Wall
- Complex semi rigid structure used to separates the exocellular and intracellular environments
- It’s also important in maintaining osmotic pressure and prevent the cell from popping
- Gram positive cell walls
- Gram negative cell walls
What is this structure and its function
Cell membrane
Flexible semipermeable phospholipid bi layer which regulates the transfer of particles into the cell
What is this structure and its function
Fimbriae
Fimbriae are long filamentous polymeric protein structures located at the surface of bacteria cells. They enable the bacteria to bind to specific receptor structures and thereby to colonies specific surfaces.
What is this structure and its function
Plasmids
Additional genetic information which can be used by the bacteria or transferred to another bacteria through congregation. This can provide a survival advantage.
What are endospores
Endospores are formed by certain bacteria. They are released when environmental conditions are unfavourable which forces the bacteria into a dormant state that lasts until conditions become favourable again.
E.g. Clostridium tentani (Tetanus)
What’s the structure of a gram positive cell wall
- A thick layer of peptidoglycan
- Plasma membrane
- Has teichoic acid
- Turns purple after gram stain due to the thick peptidoglycan which can hold the stain well
What’s the structure of a gram negative bacterial cell wall
- Thin layer of peptidoglycan
- Outer cell membrane
- Porins
- Lipopolysaccharides (LPS)
- Turns pink after gram stain because the thin peptidoglycan layer doesn’t hold the purple stain well.
What are the Macromolecules of the Cell Wall
- Peptidoglycan
- Teichoic Acid (only in gram positive)
- Lipopolysaccharides (LPS) (only in gram negative)
What are the different shapes of bacteria
- Coccus (sphere)
- Bacillus (rod)
- Spirochete (spiral) - don’t really need to know
What macromolecule is found in gram indeterminant bacteria cell wall
Mycolic Acid
What are the phases of bacteria growth
- Lag time
- Exponential phase
- Stationary phase
- Death phase