Midterm Flashcards
Antonie van Leeuwenhoek
1650, 200x microscope, described animalcules
Robert Hooke
1635, cork, named cells, micrographia
Francesco Reid
Attacked spontaneous generation with cheesecloth on meat experiment
Pasteur used
Swan neck flasks to prove spontaneous generation wrong
Germ theory of disease
Defining there is an etiological agent that causes disease
Etiological agent
Something that fits Kochs postulates
Robert Koch
Defined the postulates and discovered tb bacterium
Kochs postulates
Present in all cases, can be cultivated in pure culture away from the body, cells then cause disease in healthy individual, organisms can be reisolated and shown to be the same
Beijerick
Created selective plates
Fleming
Discovered penicillin
Edward Jenner
Small pox vaccine
first genome sequenced
1995
Coccus
Round
Filamentous
Long and thin
Spirochete
Long thin and waved
Spirrilium
Long but fatter
Rod
Rod
Size of bacteria
0.2-700um
Phosphatidylethanolamine
Fatty acid with glycerol and ethanolamine chains
Bacterial bilayer strengthened by
Hopanoids
Archaea membrane are different because
No fatty acids, have phytanyl instead which forms biphytanyl
Secretion sequence to leave cell
SecA
Secretion sequence to insert protein in membrane
Signal recognition particle
Bacterial cell wall made of
Peptidoglycan
Peptidoglycan is made of
4 amino acids and a carbohydrate hexose
Bonds in peptidoglycan
Peptide bonds across the wall and glycosidic bonds along it
LPS
Lipopolysaccharide
Head group of bacteria LPS
Lipid A
Carbohydrate group of bacteria LPS
O-specific polysaccharides
Gram positive
Purple
Gram negative
Pink
Bacterial capsule role
Pathogenesis and biofilm formation
Bio films contain
75% glycocalyx matrix and 25% bacterial cells
Formation of a biofilm
Attachment, colonisation and growth
Peritrichous
Uniform distribution all over the body
Polar flagella
1 at one end
Lophotrichous
Multiple flagella at one end
Amphitrichous
2 flagella- one at each end
Endo spore
Dormant stage of life cycle of bacteria
Layers of endo spore
Exosporium and spore coat surround it
Antibiotic
A naturally occurring antimicrobial
Endospore formers
B serius and c diff
Naturally occurring antibiotics
Aminoglycosides, macrolides, tetrocyclines, penicillin g
Aminoglycosides
Inhibit 30s ribosome, toxic
Glycosides
Hexose and pentode groups
Macrolides
Lactone ring, eg. Erythromycin
Tetracyclines
Broad spectrum, 4x6 carbon rings and side chains
Penicillin g
Cell wall synth, destroyed by betalactamases
Synthetic antimicrobial drugs
Synthetic penicillins, quinolones, ciprofloxacin
Semisynthetic penicillins
Adding a different R group to make them beta lactamase resistant
Semisynthetic penicillin examples
Methicillin, oxacillin and ampicillin
Quinolones
Inhibits DNA gyrase
Ciprofloxacin
Part of fluoroquinilines
Bacteriostatic
Targets protein synthesis
Bactiocidal
Kills cells (cells still there but not viable)
Bactiolytic
Lyse the cells
Vancomycin
Inhibits cell wall synth, used against c diff
Methicillin
No longer used, inhibits cell wall synth, MRSA
MRSA
Methicillin resistant s. Aureus
Mechanisms of resistance
Lack structure to inhibit, impermeable, inactivate the antibiotic, modification of target, effluent of antibiotic
Penicillin resistance
Beta lactamase
Streptomycin resistance
Phosphorylation
Spread of antibiotic resistance
On R plasmids
RTF
Resistance transfer factor
Central dogma
DNA to mRNA to protein
2 methods of classifying bacteria
Baltimore method and ICTV method
ICTV
International committee on taxonomy of viruses
Virus nucleocapsid
Capsid and nucleic acid
Virus genome
5kb to 1.2mbp
Virophage
Virus that infects the mimivirus
Bacteriophage
Virus that infects bacteria
Virulent bacteriophage
Kills the cells
Temperate bacteriophage
Can follow lytic or lysogenic pathway
Lysogen
A state where most virus genes are not expressed and the pro phage is replicated in synchrony with the host chromosome
Pro phage
Viral genome
Lysogens
Cells that harbour a temperate virus
Virus lifecycle
Attachment, penetratin, synthesis, assembly, lysis
Bactiophage lambda
Infects E. coli
Gene for the lysogenic pathway
cL
Gene for the lytic pathway
Cro
The lytic pathway
Cells lysed. Cro dominates.
Phage proteins formed and burst from cell
N protein
An antiterminator that means cII and cIII and Q proteins are formed
Q protein
An antiterminator that allows the phage proteins to be transcribed in the lytic cycle
Lysogenic pathway
Phage DNA integrates with bacterial chromosome via recombination.
Domination by cL
CII is transcribed from
Pe site
CL
Lambda repressor prtoein that blocks synthesis from Pr
Binding of cro to the operator
Inhibits CL formation so no promotion of lysogeny
Binding of CL
Inhibits Pr= no cro so blocks lytic pathway
To maintain lysogeny
CL needs to be constantly present
Taxonomy
Science of classification