Intro To Bacteriology Flashcards
5 essential elements of prokaryotes
And the other elements
- cell wall
- cell membrane
- nucleoid / genetic material
- ribosomes
- capsule / slime layer
- mesosome
- inclusions
- pili
- flagella
- periplasmic space
List the 3 architectural regions of prokaryotes and describe
1 cell envelope
-cell wall, membrane and capsule
2 cytoplasm
-mesosome , nucleoid , ribosomes, inclusion
3 appendages
- flagella
- pili
Function of nucleoid , ribosomes and membrane
- dense region in cyto with genetic material
- controls cellular biological activities
-protein synthesis
- selective barrier
- maintains cell ionic contant
- set up and maintain cell polarity
Describe the capsule / slime layer structure, characteristics and function
-gelatinous polysaccharide or peptide
/outer covering of cell
-called capsule is firmly attached to cell and slime layer is loosely attached
-has glycocalyx layer
- attachment to surfaces
- protect against phagocytosis
- nutrient reserve
Antigenic designation of capsule and appearance on microscope
- K
- unstained halo surrounding cell
Where isn’t capsule found
-mycoplasma and thermoplasma
Outcome of digestion of cell wall
Cell wall lost and in
- in gram positive becomes protoplast
- in gram negative spheroplasts
Two types of cell wall and describe
1 gram positive
- has thick peptidoglycan layer with techoic acid and lipotechoic acid attached
- in contact with cell membrane
- stains blue
2 gram negative
- has thin peptidoglycan layer and outer membrane
- in contact with cell membrane
- outer membrane has porins and polysaccharides
- stains red
What is mesosome and what is bacteria membrane lacking ( diff from eukaryotes)
- inward intrusions of membrane
- cholesterol
Size of prokaryotic and eukaryotic ribosomes
- 30S and 50S to make 70S
- 40S and 60S to make 80S
Types of prokaryotic inclusions and function and common function of all
1 volutin- ( Barnes Ernst ) energy and phosphate storage
2 lipid granules - carbon and energy storage
3 polysaccharide granules - glucose monomers source of carbon and energy storage
-nutrients reserve
Plasmids structure, characteristics and function
- extra chromosomal DNA
- found in both pro and eukaryotes
- larger ones found in gram negatives
Cell well function
- protect against osmotic lysis
- prevent excessive intake of water
- confer rigidity and strength
What is a bacteriophage
-virus particle which parasitizes bacteria by infecting it
Describe bacteriophage cycle ( both roots )
Lysis root
- bacteriophage attaches to cell wall of uninfected host on phage receptor using attachment proteins
- penetration: vital dna injected into bacteria
- maturation and replication : bacterial cell machinery used to replicate vital dna and to make more viruses
- lysis of cell : release
Lysogenic cycle
- after injected viral DNA incorporates into bacteria dna
- replication of lysogenic bacteria
- prophage separates from bacteria dna
- prophage causes replication or re-incorporates into bacteria dna
What is a bacteria endospore and function
- unique structures found on some genera
- responses to environmental stimuli
- resistant to heat, radiation and harsh chemicals
What is flagella and function ( including structure)
- long filamentous Axial structure made of fibrillin protein surrounded by cell membrane
- responsible for bacteria motility
- has filament attached to hook attached to basal body ( inside cell wall in contact with membrane)
Types of flagella and description
- atrichous no flagella at all
- monotrichous : 1 flagella protruding at one end
- lophotrichous : numerous flagella protruding at one end
- amphitrichous : numerous flagella protruding at opposite ends
- peritrichous : numerous flagella protruding at all ends
Describe pili / fimbrilae structure and function
-made of fibrillin but less motile , thinner and shorter but more numerous than flagella
- sex pili used in conjugation
- used to attach to surfaces
- protect against phagocytosis
List the 3 types of genetic exchange in prokaryotes
1 transduction
2 conjugation
3 transformation
Describe transformation
- recipient DNA takes up donor DNA fragments
- recombination occurs ( joining of fragments to recipient DNA
- recipient DNA genetically transformed and unrecombined fragments are degraded
Describe conjugation
- donor Bacteria with plasmid extend sex pili to recipient without and attached then fuses
- relaxasome , DNA polymerase and transferasome replicated the plasmid and transfer to recipient bacteria
- bacteria beak off and now both have plasmid and sex pili l
List the two types of transduction
1 general
2 specialized
Describe general transduction
- phage infects bacteria
- host DNA hydrolyzed and phage DNA and proteins made by cell.
- occasionally bacterial DNA packed in phage caspid which now becomes transducing phage which infects new host
- recombination occurs and recombinant has diff genotype from donor or recipient
Describe specialized recombination
- bacterial cells has prophage ( viral DNA ) integrated between genes
- occasionally prophage exits incorrectly taking adjoining genes with it
- phage carries bacterial and phage DNA
- infect new host and recombination occurs and recombinant has diff genotype from donor or recipient
