List characteristics of Prokaryotes
- Small and primitive
- All bacteria
- No membrane bound organelles but has ribosomes
- No nucleus, but has nucleoid
- Cell wall with peptidoglycan
- One circular chromosome
List characteristics of Eukaryotes
- Large and complex
- All other organisms
- Membrane-bound organelles
- Nucleus and nuclear membrane
- No cell wall, but has cell membrane
- Many chromosomes, not circular
How is bacteria classified?
- Structure and shape: Cell wall, Antigens, Morphology
- Metabolic processes: Aerobic / anaerobic / facultative, Fermentation of sugars
- Other biochemical reactions / production of specific enzymes or toxins
- DNA sequence
Is a baterium a prokaryote or eukaryote?
prokaryote
Is a fungus a prokaryote or eukaryote?
eukaryote
How is a fungus classified?
It has its own kingdom
What are the 3 different types of fungi?
yeasts, mould, dimorphic (yeast/mould depending on temperature)
What is distinctive of fungi?
- distinct cell membrane: ergosterol
- distinct cell wall
What is the difference between yeasts and moulds in terms of how long they take to grow?
- Yeasts: 2-3 days
- Moulds: days-weeks
What is the difference between yeasts and moulds in terms of temperature?
- Yeasts: grow best at 35°C
- Moulds: variable temperatures (often 25°C)
What is the difference between yeasts and moulds in terms of colonies?
- Yeasts: colonies look like bacteria
- Moulds: “fluffy colonies”
What are examples of yeasts?
Candida spp, Cryptococcus
What are examples of moulds?
Aspergillus, Penicillium
Define parasite
An organism that lives on or in a host and gets its food from or at the expense of its host, not a specific class of organism.
List characteristics of protozoa
Eukaryotic
Unicellular
Multiple classes
What are examples of protozoa?
Malaria, Trichomonas, Giardia, amoebae
Name characteristics of metazoa
- Trematodes, nematodes, cestodes etc.
- Eukaryotic
- Multicellular
- Multiple classes
What are examples of metazoa?
Hookworm, whipworm, bilharzia
Name important facts about bacteria nomenclature
- Genus and species usually tells you something about the organism, the disease it causes or the person who discovered it.
- Often derived from Latin or Greek
- Either underlined or written in italics.
- Only the first letter of the genus is written in uppercase, and you may use this first letter as an abbreviation (eg. E. coli).
In the example: Entamoeba coli, which one is the genus name and which one is the species name?
- Entamoeba: genus name
- coli: species name
What are the 4 groups of bacteria?
- Mycobacteria
- Gram positive
- Gram negative
- Atypical bacteria
What is the structure of Gram positive bacteria?
- Stain purple
- Thick peptidoglycan layer with no outer membrane
- Cross-linking between peptidoglycan molecules: some antibiotics target cross-link sites
What is the structure of Gram negative bacteria?
- Stains pink
- Thin peptidoglycan layer with outer membrane
- Contains lipopolysaccharides: endotoxins in endotoxic shock
- Periplasmic space contains β-lactamase enzymes
Describe the structure of mycobacteria
Rod- shaped organisms with complex cell wall, acid-fast stain
