MODULE 3 (L18-21)
18A+B – Microbiology and ‘One Health Concept’ Part 1+2
Diversity of Increasing scale of complexity (from the least complex to most complex)
Micro-
organisms 1. Viruses
- The smallest & simplest biological entities
- Dp on host cell for replication & metabolism
- Small in size & genome content but have large effects on other
organisms & ecosystems
- Virus replication – viruses have to be inside another host cell to
replicate
- Do not have their own metabolism – need to steal energy &
materials from the host cell to make more virus particles
- e.g., Common human viruses that cause diseases:
2. Bacteria
- Sometimes aka prokaryotes
- Unicellular structure
- Smallest free-living organisms
- Have own metabolism & replication (unlike viruses)
o They can make copies of themselves
- Dif morphologies of bacteria
,- Simple morphologies of bacteria conceal complex biochemistry and
interactions
- Some bacteria (chemolithoautotrophs) can even grow on inorganic
compounds
o They don’t need organic materials to make more copies of
their cells
- Bacteria responsible for ecosystem processes – primary pd &
decomposition
3. Fungi
- Large complex cells (Eukaryotes); nucleus, mitochondria
o Eukaryotes = having membrane bounded nucleus
o Their DNA organised in nucleus
o Eukaryotes have other complex organelles – mitochondria,
Golgi apparatus, endoplasmic reticulum, etc
- Can be unicellular (e.g., yeasts/multicellular; e.g., moulds)
o Two kinds of fungi: yeasts & moulds
- Some fungi can have both macroscopic & microscopic parts (e.g.,
fruiting body vs. Spores of mushrooms)
o Can be classified as microbes bc they have some microscopic
structures like spores, individual filaments, hyphae
o May have macroscopic structures (e.g., fruiting body of a
mushroom)
- Diverse morphologies of fungi
,Some are beneficial (as it can be used in food manufacture like fermented
pd) while some are harmful/causing diseases
4. Protists
- Extremely diverse in morphology, lifestyle, & their evolutionary
histories
o Difficult to classify due to huge diversity
- Large complex cells (Eukaryotes); nucleus, mitochondria
- Protozoa: protists that are animal-like (predatory)
5. Algae
- Other kind of Protists
- Large complex cells (Eukaryotes); nucleus, mitochondria
- Algae: plant-like protists; photosynthetic eukaryotes
- Algae have chloroplast (KEY distinction between algae & fungi)
- Some protists cannot easily be classified as ‘algae’ or ‘protozoa’
- Exceptions to rules are v common in
, - Unicellular; they don’t make large multicellular macroscopic forms
- At cellular level, they the same as seaweeds
History of IMP Hooke - English scientist
ideas, - The idea of ‘cells’
discoveries, - 1664 – Robert Hooke describes microscopic structure
scientists in of blue moulds, using a 30x magnification microscope
microbiology - First to use the word ‘cell’ - his book “Micrographia”
(1665) v influential due to the excellent artwork
Van - Discovers bacteria + protists
Leeuwen - 1684 – Antonie van Leeuwenhoek develops powerful
hoek microscopes (300x mag.), discovers “wee
animalcules” - first evidence of bacteria & protists
- He is considered the ‘father of microbiology’
18A+B – Microbiology and ‘One Health Concept’ Part 1+2
Diversity of Increasing scale of complexity (from the least complex to most complex)
Micro-
organisms 1. Viruses
- The smallest & simplest biological entities
- Dp on host cell for replication & metabolism
- Small in size & genome content but have large effects on other
organisms & ecosystems
- Virus replication – viruses have to be inside another host cell to
replicate
- Do not have their own metabolism – need to steal energy &
materials from the host cell to make more virus particles
- e.g., Common human viruses that cause diseases:
2. Bacteria
- Sometimes aka prokaryotes
- Unicellular structure
- Smallest free-living organisms
- Have own metabolism & replication (unlike viruses)
o They can make copies of themselves
- Dif morphologies of bacteria
,- Simple morphologies of bacteria conceal complex biochemistry and
interactions
- Some bacteria (chemolithoautotrophs) can even grow on inorganic
compounds
o They don’t need organic materials to make more copies of
their cells
- Bacteria responsible for ecosystem processes – primary pd &
decomposition
3. Fungi
- Large complex cells (Eukaryotes); nucleus, mitochondria
o Eukaryotes = having membrane bounded nucleus
o Their DNA organised in nucleus
o Eukaryotes have other complex organelles – mitochondria,
Golgi apparatus, endoplasmic reticulum, etc
- Can be unicellular (e.g., yeasts/multicellular; e.g., moulds)
o Two kinds of fungi: yeasts & moulds
- Some fungi can have both macroscopic & microscopic parts (e.g.,
fruiting body vs. Spores of mushrooms)
o Can be classified as microbes bc they have some microscopic
structures like spores, individual filaments, hyphae
o May have macroscopic structures (e.g., fruiting body of a
mushroom)
- Diverse morphologies of fungi
,Some are beneficial (as it can be used in food manufacture like fermented
pd) while some are harmful/causing diseases
4. Protists
- Extremely diverse in morphology, lifestyle, & their evolutionary
histories
o Difficult to classify due to huge diversity
- Large complex cells (Eukaryotes); nucleus, mitochondria
- Protozoa: protists that are animal-like (predatory)
5. Algae
- Other kind of Protists
- Large complex cells (Eukaryotes); nucleus, mitochondria
- Algae: plant-like protists; photosynthetic eukaryotes
- Algae have chloroplast (KEY distinction between algae & fungi)
- Some protists cannot easily be classified as ‘algae’ or ‘protozoa’
- Exceptions to rules are v common in
, - Unicellular; they don’t make large multicellular macroscopic forms
- At cellular level, they the same as seaweeds
History of IMP Hooke - English scientist
ideas, - The idea of ‘cells’
discoveries, - 1664 – Robert Hooke describes microscopic structure
scientists in of blue moulds, using a 30x magnification microscope
microbiology - First to use the word ‘cell’ - his book “Micrographia”
(1665) v influential due to the excellent artwork
Van - Discovers bacteria + protists
Leeuwen - 1684 – Antonie van Leeuwenhoek develops powerful
hoek microscopes (300x mag.), discovers “wee
animalcules” - first evidence of bacteria & protists
- He is considered the ‘father of microbiology’
