BM1022 Flashcards
(20 cards)
Paul enrlich
Discovered chemotherapeutic agent to treat syphilis
Edward Jenner
He pioneered the vaccination before world war 2 (1940s)
Successes of treatment and prevention
Small pox virus no longer exists in a viable form
Vaccination programmes for polio have all but eliminated the disease form the wesern world
Classification of life
Archaea
Bacteria
Eucarya
Prokaryote
Pro (primitive) karyote (nucleus)
Bacteria alone possess this cell type
No membrane apart from cytoplasmic
Are very small bc the cell structures required to function are minimal
Eukaryotes
Ey (true/normal)
Microbes with this cells are fungi
Protozoa, and multicellular parasites
Have membrane bound structure
Viruses
Not cells
Must associate with a living cell in order to reproduce
Carry genetic info, have no membranes and can’t generate energy
Prions
Only protein, no cellular structure
No nucleic acid
Basic principles of microbial physiology related to smallness
The smaller the cell the greater the surface volume ratio
Small cells have more efficient exchange with the environment
Cell size is said to be inversely related metabolic rate and thus growth
Infection must be taken seriously and treated IMMEDIATELY
Prokaryote cytoplasmic membrane
No sterols generally
Respiration is associated with the bacterial plasma membrane. Respiration is a process which consumes oxygen and gives off carbon dioxide and results in the liberation of energy
Cell walls
Most microbes possess a cell wall, expectioms include mycoplasma and Protozoa
Cell wall of bacteria
Function; confers rigidity, shape and integrity
Lysozyme removes cell wall- leads to lysis
Gram-positive
Gram-negative
Possess a thicker and simpler wall than gram negative
Wall is structurally complex with a thin layer of peptidoglycan and an outer layer of lipopolysaccharide
Gram staining reaction and therapy
Antibiotics like penicillin inhibit synthesis of new cell wall material by preventing cross-linking chemical bridges forming between adjacent peptidoglycan chains. Gram negative organisms are insensitive to penicillin- outer membrane responsible
Bacteria
Prokaryotic cells which generally lack membrane bound organelles
Small, simple felled, shapes described as bacillus, coccus, and spiral
Cell walls: are mostly rendered rigid by a complex carb termed peptidoglycan
They decide by binary fission (two equal daughter cells produced ) sexual reproduction rare
Classification of bacteria
Within the prokaryotic kingdom, bacteria are assigned two names, a genus and a species
E.G. Staphylococcus aureus
Structure of bacteria
The cell wall structure of bacteria is differentiated into 2 groups by the gram stain- as either having s thick layer of peptidoglycan rich in teichoic acids (GP-blue) or thin layer of peptidoglycan with an outer membrane of lipopolysaccharides (GM-red/pink)
Extra cellular structures enable motility, attachment and transfer of genetic material
Which may enhance virulence and include dim raw, pili, flagella and capsule
Morphology of bacteria
Cocci (round)
Bacilli (rod)
Spiral (corkscrew)
Bacteria growth requirements
Aerobes- those that require oxygen for growth
Facultative anaerobes - those that can grow in the presence or absence of oxygen
Anaerobes- those that are inhibited by oxygen
Diagnosis of bacterial infection
Relies of culturing the bacteria from a clinically infected site using a medium with nutrients solidified by agar
Specific antibody detection in the patient is also utilised but is of limited value because of the general similarity between bacteria
