Structure & Function of Bacteria Flashcards
All cellular life have the following characteristics in common:
- Cell membrane (regulates flow of nutrients/waste in/out)
- DNA (genetic material)
- RNA (molecules)
- Protiens (enzymes)
- Basic chemicals(carbs,lipids,vit,minerals)
- Reproductive
- Energy
What are the 2 different types of cells? Explain the difference between the them.
PROKARYOTIC- no nucleus, no RNA processing, no organelles, has a cell wall
EUKARYOTIC- Contains a nucleus, RNA processing, organelles. Does not have a cell wall ( only in animals)
What is function/characteristics of Flagellum?
- Helps bacteria move from one place to another
- Long structures that extend beyond the surface of the cell
- Responsible for movement—>rotation propels bacterium thru environment
- Used in chemotaxis - movement towards/away from subtances & phototaxis( toward/away from light)
- Receptors for light/chemicals on surface of cell send signals to flagella, adjust speed/direction of rotation
Characteristics of Axial Filaments
- Type of Flagellum
- Simular function to flagella
- Run lengthwise along cell
- Snake like movements
What is the function of Fimbria?
- Sticky projections used by bacteria to adhere toeachother
- 100s of cells
- Shorter than flagella
- Evenly distributed over entire surface used for
attachment to host & substances - Bacteria may use fimbriae to move across a substrate or toward another bacterium via a process similar to
pulling an object with a rope
What is the function of Pili
- long hollow tubules
- 1/2 cell longer then fimbriae, Shorter then flagella
- Typically 1 or 2 per cell
- Join 2 bacteria cells & mediate transfer of DNA from 1 cell thru another ( conjugation)
- Ecoli 0157 has very strong fimbria ( walkerton, organ fail)
Characteristics of Capsule/Slime layer
- Cover bacteria in nature (lakes)
- Sticky substance surrounding outside of cell
- Composed of Polysaccharides, polypeptides, glycoprotiens
Describe Capsule
- THICK layer of cell FIRMLY attached to the cell surface
* Composed of organized repeating units of organic chemicals firmly attached to the cell surface.
What is a THINNER layer then capsule and LOOSELY attaches to the cell surface?
Slime layer
What is the function of the Capsule/ Slime Layer
- Mediate adherance of cells to eachother/surfaces
- Protect cells from engulfment
- Protect from drying
- Are used a carbohydrate reserves
A cell wall allows bacteria to resist osmotic stress T/F
True
Complex aggregation of microorganisms growing on a solid substrate mediated by fimbriae and capsule
What is Biofilm
List some characteristics of Prokaryotic cell wall
- Allows bacteria to resist osmotic stress
- Provides structure/shape ( cocci, strep, staph, bacilli )
- Asst. cells in attach to other cells/resisting anti bac drugs.
- Target cell wall of bacteria with anitbiotics
What are bacterial cell walls composed of?
Peptidoglycan
This single macromolecule is highly crosslinked, surrounds the cell complex polysacaccride and provides ridgity.
Peptidoglycan