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
Peptidoglycan mankes a structure look like _____?
Net
Desribe Gram Positive Cell Wall
- Made up of 40 layers of Peptidoglycan
* Rest made up of polysaccharides ( aka Techoic Acid)
In the gram positive cell wall, what is the purpose of the Techoic Acid?
Connects layers of the Peptidoglycan together and the liptechoic acids anchor the peptidoglycan to cytoplasmic membrane. Retains crystal violet die in gram staining procedure ( appears PURPLE)
Desribe Gram Negative Cell Wall
- Outer membrane = thin layer peptidoglycan
- Cell membrane is b/w outer membrane/peptidoglycan.
- Cell membrane is the periplasmic space
- only a thin layer Peptidoglycan
- Peptidoglycan is covered by other membrane composed of phospholipids integral protiens and lipoplysaccharides ( LPS)
What is the space called that is jelly like in nature. Located b/w the outer membrane and the cell membrane that contains Peptidoglycan, H2O, enzymes, nutrients & other substances. Gram staining appears PINK.
Periplasmic Space
Chemicals produced by the pathogen that harm tissues or trigger host immune responses that cause damage
TOXINS
What are 2 types of toxins?
Exotoxins & Endotoxins
EXTOXINS
- gram +ve and gram -ve
- most often released by gram + organisms
- protiens are actively secreted by a pathogen-usually enzymes
- destroy cellular & extra cellular structures- can affect NS and cause paralysis
