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OPTION F: MICROBES AND BIOTECHNOLOGY
IB BIO
IMPORTANT BUSINESS- Internal Assessment
- Should finish experimental trials by THURSDAY 30 JAN - If you need to schedule time with the instruments, please
sign up on the sheet on the door- Final Drafts due FRIDAY 7 FEB
- Quiz – Diversity of Microbes
- Next Wednesday! 29 JAN
MICROBES & BIOTECHNOLOGY- Diversity of microbes
- The nitrogen cycle
- Sewage treatment
- Beer, wine, and bread
- Gene therapy
- Disease and Epidemiology
DIVERSITY OF MICROBES
Objectives for today:
- Differentiate between the 3 domains of microbes
- Be able to identify gram-positive vs gram-negative bacteria
- Understand why single-celled organisms form clusters
DIVERSITY OF MICROBES
All living things can be classified into 3 different domains
1. Eubacteria
2. Archaea
3. Eukaryota
Image: http://www.learner.org/courses/envsci/visual/img_lrg/common_ancestor.jpg
EUKARYOTA- Most “complex” organisms
- Usually have larger genomes
- Only domain to have genes with introns- Largest ribosomes: 80s
EUBACTERIA- These are the single-celled organisms you are most
familiar with
- Have cell walls made of peptidoglycan
- 70s ribosomes
- Have no histone proteins
ARCHAEA- Formally classified in the same domain as eubacteria
- Single-celled organisms that look and act almost identical to eubacteria
- Cell membranes have different biochemical structure
- Eukaryotes/Eubacteria have ester bonds in membrane lipids
- Archaea have ether bonds in membrane lipids
ESTER VS ETHER LINKAGES
Image: http://classconnection.s3.amazonaws.com/865/flashcards/553865/png/ester_vs_ether1306815819523.png
ESTER VS ETHER LINKAGES
Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg
ESTER VS ETHER LINKAGES
Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg
ARCHAEA- 70s ribosomes (same as eubacteria)
- Genes do not contain introns
- Some species have histone proteins
- Occupy extreme environments
Image: wikimedia.org
Image: ucmp.berkely.edu
XXXTREME ARCHAEA- Halophiles
- Live in habitats with extremely high salt content- Found in saline lakes, e.g. Dead Sea
- Thermophiles
- Live in very hot habitats, up to 100C in some cases- Hot springs, volcanic areas, geothermal vents (black
smokers)- Methanogens
- Live in anaerobic habitats where organic matter is available
- Swamps, waterlogged soils, gut of cattle, landfills
DISTINGUISHING THE THREE DOMAINSCharacteristic Archaea Eubacteria Eukaryota
Are cell walls made of peptidoglycan?
What are the bonds in membrane lipids?
What size are the ribosomes?
Do most genes contain introns?
How many species have histone proteins?
DISTINGUISHING THE THREE DOMAINSCharacteristic Archaea Eubacteria Eukaryota
Are cell walls made of peptidoglycan?
None All None
What are the bonds in membrane lipids?
Ether Ester Ester
What size are the ribosomes?
70s 70s 80s
Do most genes contain introns?
No No Yes
How many species have histone proteins?
A few None All
DIVERSITY OF EUBACTERIA
DIVERSITY OF EUBACTERIA
1) Coccus: spherical bacteria
2) Baccilus: rod-shaped bacteria
3) Vibrio: comma-shaped rods
4) Spirilli: twisted bacteria
Some bacteria can group together to form AGGREGATES:Prefix “strepto-” form filamentsPrefix “staphylo-” form clusters
Ex. Staphylococcus form spherical clusters
COOPERATING BACTERIA – POWER TO THE PROLETARIAT MASSES
Biofilm a surface-coating colony of organisms
Pseudomonas aeruginosa produces biofilms in burned patients and in patients with cystic fibrosis. It is easier for bacteria to acquire resistance to antibiotics b/c they can cooperate and interact in different ways
COOPERATING BACTERIA – POWER TO THE PROLETARIAT MASSES
Autoinducers help coordinate the action of a group of bacteria
Vibrio fischeri is a bacterium found in sea water than is able to emit light in a process called bioluminescence. Individuals do not emit light unless they become part of a population of certain density.
V. fischeri releases an autoinducer into its surroundings. In a dense population, the concentration of the inducer becomes high enough to trigger bioluminescence.
Image: bioart.co.uk/lux/vib.jpg
ASSIGNMENT
Find one example of an archaea, eubacteria, and eukaryota that you find interesting and create a 3-6 slide powerpoint with the following:
1) Scientific name
2) Habitat/Growing conditions
3) Shape (e.g. coccus, bacillus)
4) Gram-positive or negative (if eubacteria)
5) At least one picture
6) E.C. available for going above and beyond the call of duty
DISTINGUISHING EUBACTERIA - GRAM STAINING- Eubacteria can be classified into 1 of 2 categories based
on their cell wall structure:
- Gram-positive (thick peptidoglycan cell wall)- Gram-negative (thin peptidoglycan cell wall, thin outer
layer of lipopolysaccharide and protein)
- Using a series of chemicals, we can identify the cell wall structure of eubacteria by the color they stain
- Gram-positive stains purple (POSITIVELY PURPLE)- Gram-negative stains red
Image: http://pathmicro.med.sc.edu/fox/gram-st.jpg
GRAM- VS GRAM+
Image: http://4.bp.blogspot.com/gramposandneg.jpg
EXAMPLE OF GRAM STAINED EUBACTERIA
Image: wikipedia.org