intro to micropbiologosoo Flashcards
nomenclature is
labeling/naming of the groups and the members of organisms
Binomial system
- Genus and species names – should be universal around the globe
- Both components are either italicised OR underlined
First letter of genus is always Capitalised
• Species designation is always lowercase
• Genus may be abbreviated to first letter i.e. S.aureus after first full use in text
• Species name is never abbreviated
% of organisms harmless
est 87%
what is opportunistic
under certain conditions and environment they can be harmful
% of organisms that are opportunistic
10%
% of organisms are considered to be overtly pathogenic
3%
Normal flora is
he microbes that naturally inhabit surfaces of the human body
normal flora occur at sites
exposed to, or that communicate with the external environment
e.g. skin, nasal passages, mouth, throat, urogenital tract, intestinal tract
– Blood, tissues, lower respiratory tract are regarded as sterile
– Includes bacteria, fungi, protozoa and viruses
where can most normal flora be found
large intestine
Robert Hooke (1665)
– Wrote first book detailing observations with a microscope
– First person to describe a ‘cell’
potentially plant or skin cell (large one)
Antoni van Leeuwenhoek (1673)
– Developed a microscope with a moveable stage
– First to describe bacteria including their shapes
– Very secretive, knowledge lost for over 100 years
Louis Pasteur (1861)
Disproved theory of spontaneous generation (Abiogenesis)
– Discovered pasteurisation (originally used to prevent spoilage of wine)
debunked the idea peps got sick spontaneously
Joseph Lister (1870)
Credited with developing antisepsis for surgery
– Experimented with dressings soaked in carbolic acid (used as an antiseptic)
Robert Koch (1883)
First to study Anthrax and Tuberculosis (bacteria that cause them)
– Found that microorganisms can invade other organisms and cause disease
• Koch’s postulates - germ theory of disease
– Contributed to developing staining methods for microbes
- certain microbes cause certain diseases
Ignaz Semmelweis (1847)
First to use handwashing in clinical practice
In 1847 in Vienna, he introduced handwashing – reduced obstetrics mortality from 18% to <1%
Physicians continued to refuse to wash hands….came from high society so essentially low society is the problem not them
Hand washing only accepted years later after work by Pasteur, Lister, Koch
Koch’s Postulates (Germ Theory) steps
- The specific causative agent must be found in every case of an infectious disease
- The disease organism must be isolated in pure culture (prove its there)
- Inoculation of a sample of the culture into a healthy, susceptible animal must produce the same disease
- The disease organism must be recovered from the infected animal
Summary: A specific infectious disease is caused by a specific microbe
3 domains classification of life
Eubacteria (same as bacteria)
– Gram positive/negative bacteria
– Cyanobacteria
– obtain energy through photosynthesis
Archaea (specialised single cell organisms that resemble bacteria)
– Methanogens – grow in the absence of O2 and produce methane (CH4)
– Halophiles – grow/live in areas of high salt concentration (>5 times ocean 3.5%, >17%)
– Thermophiles – grow in areas of high temperature (45 ̊C to 122 ̊C)
Eucarya
Protozoa – Algae – Fungi – Plants – Animals
classifications of microorganism
prokaryotes
eukaryotes
prokaryotes structure + types
• Archaea • Bacteria lack a nuclei in cell No nucleus - DNA unenclosed No nuclear membrane Smaller 0.1 – 10 μm Complex cell walls e.g. peptidoglycan
capsule - nucleoid - cell wall + membrane - ribo - flag - fimbriae
eukaryotes structure + types
- Fungi
- Protozoa
- Algae
DNA inside nucleus surrounded by a Nuclear membrane
cell membrane NB: Not a cell wall
Larger 10 – 100 μm
Animals and Protozoa lack cell walls • Have a cell/plasma membrane contain a nuclei in cell
Plants, algae and fungi = simple cell walls
golgi = nucleus with nucleolus - ER - ribo
Algae
• Eukaryotes
• Photosynthetic (contain chlorophyll like plants)
– Obtain energy from sunlight
• Produce most of the world’s O2
• Food for water life (phytoplankton) •
Unicellular or multicellular
- Multicellular e.g. large algae - seaweed, kelp - Unicellular - ponds, lakes, oceans e.g. diatoms
Protozoa
Single celled Eukaryotes
Most are motile (can move by themselves)
– Psuedopodia, cilia or flagella
Live mostly in water, some in animal hosts & cause disease
e.g. malaria and several that cause diarrhoea
fungi differs from animals and plants and types
Differ from plants because fungi do not use photosynthesis to obtain energy
Differ from animals because fungi have a cell wall
Two types:
Moulds
Yeasts
mould
fungi
– multicellular
– produce hyphae (filaments)
– reproduce sexually and asexually (spores)
