intro To Microorganisms Flashcards
What is a cell ?
Cells are the fundamental units of life
All living organisms are composed of cells
All cells come from pre-existing cells
All living organisms are made of cells;studying cells can provide info about life
What are eukaryotes
The eukaryotic cell have membrane bound compartments within the cells
Nucleus-contains DNA
What are prokaryotes ?
Have no nucleus but DNA is found in the nucleoid
No membrane bound organelles
What are microorganisms
Any organisms that cannot be seen by the naked eye.
Examples of eukaryotic microorganisms
Protista
Fungi
Plantar
Animalia
Both Protista and fungi kingdoms contain single celled organisms which are microscopic
What are viruses ?
Not microorganisms because NOT CELLULAR
So not alive but are infectious agents
Add
Pro vs Euk cells
Pro. Euk
Cell membrane Yes. Yes
Nucleus. No. Yes
Organelles. Few. Yes
Size. 1-10 mm. 10-100mm
Multicellular. No. Yes
Although may form
Chains/clusters
Cell bio and microbiology shaking hands
All prokaryotes are microorganisms
Yeast are microorganisms
Protists are microorganisms
What are prokaryotes divided into ?
Are divided into 2 groups
-archae
-bacteria
Hugely abundant on earth
Can be found everywhere
Still little knowledge
Archae
Not very well studied
Live in a range of environments
4 groups of archae
-Crenarchaeota
-Eukarchaeota
-Karoarchaeota
-Nanoarchaeota
What are Crenarchaeota ?
-can survive in environments where other organisms can’t
-either thermophillic ,acidophillic or both
-grow best at pH 2-3
Maintain internal pH of 5.5-7
What are Euryachaeota ?
-Some Euryachaeota prod methane by reducing CO2 (methanogens)
-a 1/3 of methane in the atmosphere comes from methanogens living in the guts of ruminants (cow)
-some are extreme halophiles (love salt)
-Live in all types of salty solutions (dead sae)
-contain pink pigment easy to see
Korachaeotes and Nanoarchaeotes
Korachaeotes DNA isolated from marine hydrothermal vents and freshwater hot springs
-none grown n pure cultures
Nanoarchaeotes are parasites living in Ignicoccus calls
-both organisms cultured together
Types of bacteria
Proteobacteria (e.g. Escherichia)
•Largest group
•Gram negative
Firmicutes (e.g. Staphylococcus, Bacillus)
•Mostly Gram positive but some stain Gram negative
•Have low GC to AT ratio in DNA base pairs
Actinobacteria (Mycobacteria)
•Gram-positive bacteria
•High GC to AT ratio in their DNA
Non-proteobacteria, Gram negative (e.g. spirochetes))
Gram classification
-most bacteria are divided into 2 groups based on cell wall
-different cell walls stain diff
Either
Gram positive or negative
