Option F – Microbes and Biotechnology
The three Domains of Life: Archaea
Prokaryotes
Eukaryotes
This distinction was made using rRNA – Ribosomal RNA!
F.1.1F.1.2Why do we need to differentiate organisms into three
domains?
BACTERIA ARCHAEA EUKARYOTA
HISTONES ASSOCIATED WITH DNA
Absent Proteins similar to histones bond to DNA
Present
PRESENCE OF INTRONS
Rare or absent Present in some genes
Frequent
STRUCTURE OF CELL WALLS
Made of chemical called petidoglycan
Not made of peptidoglycan
Not made of peptidoglycan; not always present
CELL MEMBRANE DIFFERENCES
Glycerol-ester lipids; unbranched side-chains, d-form glycerol
Glycerol-ether lipids; unbranched side-chains, I-form of glycerol
Glycerol-ester lipids; unbranched side chains: d-form of glycerol
Key distinguishing factors between the domains…. F.1.3
• Found in a broad range of habitats:- Ocean surface- Deep ocean sediments- Oil deposits
They are always found in extreme conditions. Examples include:• Halophiles - water with high salt concentrations• Thermophiles - Close to boiling water Tº• Methanogens - anaerobes, give off methane in
cattle’s intestine
Archaea F.1.4
Some bacteria can group together to form AGGREGATES:
Prefix “strepto-” form filamentsPrefix “ staphylo-” form clustersEx: Staphylococcus form spherical
clusters.
Some types - • Coccus: spherical bacteria• Baccilus: rod-shaped bacteria• Vibrio: comma shaped rods• Spirilli: twisted bacteria
Diversity of Eubacteria
Look at all the shapes!
Bozeman video on diversity of LifeSource: http://www.dnatube.com/video/28855/Diversity-of-Life-on-Earth
F.1.5
Biofilms are a surface - coating colony of organisms.Biofilms are found in burned patients and in patients with cystic fibrosis. P. aeruginosa is the most commom cause of death of patients with cystic fibrosis
Example: Pseudomonas aeruginosa
F.1.6
Staphylococcus
What benefits do you think it offers for bacteria to form an aggregate?What is common among patients who are at risk for Biofilms formation?
https://www.youtube.com/watch?v=J_81F2TUHJs
What’s the downside?
Check out this video and outline the ways in which Biofilms are worse than a regular infection.
Also take note of the ways in which Biotech companies can detect and start to treat Biofilms.
https://www.youtube.com/watch?v=QU1UCz6Kp_I
F.1.6
Check out this video on the life-cycle of a biofilm.
Autoinducers: help coordinate the action of a group of bacteria. F.1.6Vibrio fischeri a Gram - negative bacterium found in sea water that is able to bioluminiscence once a population reaches a certain density
https://www.youtube.com/watch?v=9jIxuS9Skgg
Gram-positive vs Gram-negativeWhat’s the big deal?
Take a look at the differences between the cell wall structure –
What are some key differences?• Think about
Lipopolysaccharide content• Think about Thickness of
peptidoglycans
F.1.7
F.1.8Viral Structure
Key Components:• Capsid - with or without envelope
surrounding• DNA or RNA • dsDNA or ssDNA• dsRNA or ss RNA
Consider all of the diversity present in such a small organism – how does this contribute to the difficulty we have treating them?
IB Practice Questions(a) Identify the type of pathogen shown on the
electron micrograph, giving reasons for your answer. [2]
(b) Label the parts of the cell walls in Gram-positive Eubacteria and Gram-negative Eubacteria shown to the right.[3]
(b) I. peptidoglycan;II. outer membrane/layer of
lipopolysaccharide and protein;III. peptidoglycan;
(a) virus;protein coat;RNA/riboprotein; 2 max
In-class InquiryYou and a partner should research one of the following microbes:• Saccharomyces• Amoeba• Plasmodium• Paramecium• Euglena• Chlorella
You should model your organism (think paper/clay) and be able to describe orally the following functions of your organism:
DomainNutritionLocomotionCell Wall?Gram +/-Chloroplasts?Cilia/FlagellaInteraction with humans?
Once you have orally checked off, add your data to the class set on the SMARTBoard.
F.1.9
Genus Saccharomyces Amoeba Plasmodium Paramecium Euglena Chlorella
Nutrition Heterotrophic: feed on glucose and other organic compounds absorbed from their surroundings
Heterotrophic: feed on smaller organisms and detritus by endocytosis
Heterotrophic: feed parasitically on red blood cells by digesting the hemoglobin
Heterotrophic: feed on smaller organisms and detritus by endocytosis
Photoheterotrophic: they possess chloroplasts and take organic matter by endocytosis
Autotrophic: they possess chloroplasts and synthesize organic compounds by photosynthesis
Locomotion Non- motile Move by a flow of cytoplasm to form outgrowths
Some stages in the life cycle can glide over surfaces
Move by beating their cilia rhytmically
Move by beating their flagellum
Non-motile
Cell wall Made of chitin absent absent absent absent Made of cellulose
Human Interaction?
Beer, Wine Fresh Water Environments
Infections - Malaria Marine Environments
Alertness to pollution
Used in Medicine
Comparing Microbes F.1.9
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