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NadiaA

Microbial Diversity
LO:
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Understand metabolic diversity and (microbial diversity)

Microorganisms can be classified according to their nutritional pattern;
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Where do they get their carbon from?
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autotrophs
 self-feeders
 e
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chemoautotrophs, photoautotrophs
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g
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8 billion years
Prokaryotes

No true nucleus
Genetic material consists of ‘naked’ DNA;
Single circular chromosome not associated with
histone proteins in bacteria, but associated with
histones in archaea
Smaller cells;
Average cell diameter of rods are 0
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g
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g
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g
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g
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E
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in plants the material is cellulose
Fungi- chitin cell wall
Cell division by mitosis
Sexual recombination does occur- meiosis

Cell wall material is different and complex e
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Eubacteria has cell wall made of peptidoglycan
Archaea has a cell wall made of pseudomurein
Cell division by binary fission NOT MITOSIS
No sexual recombination occurs- there is only
the transfer of DNA
e
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bacteria, archaea

e
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fungi, protozoa, algae

Note that chloroplasts and mitochondria are a form of prokaryotes that live in us- eukaryotes
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It is the DNA that is wrapped around histone proteins, allowing it to tightly coil
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g
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Usually has 1 circular chromosome that is haploid
Some contain plasmids
Naked DNA- DNA is not associated with histones
Genes do not contain introns
Some have flagella
Reproduce by binary fission
70S ribosomes
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NadiaA
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Enclosed by a cell membrane and ridged cell wall
Cell wall contains peptidoglycan (sugar polymer)
The chemical composition of the cell wall varies e
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many have a lot of peptidoglycan and
some have few and, this affects the ability to take up certain stains/ dyes
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Archaea
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Live in extreme environments
3 groups;
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Extreme halophiles- salt living
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g
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g
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g
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g
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They form spores to help them in such situations
Multicellular fungi e
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moulds, mushrooms
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They form mycelia/ hyphae
Largest
Fungi reproduce by several mechanisms e
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Dimorphic fungi= fungi that don’t know if they want to be unicellular or multicellular-e
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these can grow into mould or yeast depending on environmental stimuli (such as
temperature, CO2)

E
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Blastomyces dermatitidis
Protozoa
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Protozoa are chemoheterotrophs
unicellular
Some are free living and some are parasites
Have typical eukaryotic features e
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 Membrane bound organelles
 Multiple linear chromosomes
 DNA associated with histones
 Genes contain introns and exons
 80S ribosomes
Don’t have a cell wall
Have 3 mechanisms of movement

Some divide asexually and others divide sexually;

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o They can reproduce asexually;
 Binary fission- one cell splits into two
 Schizogony- nucleus divides many times before cell divides, the single cell separates into
daughter cells
 Budding- bud forms and pinches off parent cell
o Or they can reproduce sexually by fusion of gametes e
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plasmodium
Some produce cysts

Algae
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Are photoautotrophs
They are oxygenic
derived from cyanobacteria
They have different pigmentation
Have many eukaryotic features; organelles, multiple linear chromosomes, genes have
introns and exons, DNA associated with histones, 80S ribosomes
cellulose cell wall
unicellular or multicellular
Live in water e
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snow, freshwater, marine
lack organs found in plants such as roots
There is a debate to whether viruses are living or not
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