This document provides information about microbes and biotechnology for an IB Biology internal assessment. It discusses the diversity of microbes, including the three domains of life and distinguishing characteristics. Key dates are provided for experimental trials, final drafts, and an upcoming quiz. The document then covers the nitrogen cycle, sewage treatment, uses of microbes in food production, gene therapy, and epidemiology. Details are given on the domains of Archaea, Eubacteria, and Eukaryota. Characteristics like cell structure, membrane lipids, and ribosome size are compared. Examples of extreme archaea that live in salty, hot, or anaerobic conditions are described. The document concludes with assignments on gram staining of bacteria and

1. OPTION F:
MICROBES AND
BIOTECHNOLOGY
IB BIO

2. 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
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Next Wednesday! 29 JAN

3. MICROBES &
BIOTECHNOLOGY
-
Diversity of microbes
-
The nitrogen cycle
-
Sewage treatment
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Beer, wine, and bread
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Gene therapy
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Disease and Epidemiology

4. DIVERSITY OF
MICROBES
Objectives for today:
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Differentiate between the 3 domains of microbes
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Be able to identify gram-positive vs gram-negative bacteria
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Understand why single-celled organisms form clusters

5. 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

6. EUKARYOTA
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Most “complex” organisms
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Usually have larger genomes
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- Only domain to have genes with introns
Largest ribosomes: 80s

7. EUBACTERIA
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These are the single-celled organisms you are most
familiar with
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Have cell walls made of peptidoglycan
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70s ribosomes
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Have no histone proteins

8. ARCHAEA
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Formally classified in the same domain as eubacteria
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Single-celled organisms that look and act almost identical
to eubacteria
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Cell membranes have different biochemical structure
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Eukaryotes/Eubacteria have ester bonds in membrane
lipids
Archaea have ether bonds in membrane lipids

9. ESTER VS ETHER
LINKAGES
Image: http://classconnection.s3.amazonaws.com/865/flashcards/553865/png/ester_vs_ether1306815819523.png

10. ESTER VS ETHER LINKAGES
Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg

11. ESTER VS ETHER LINKAGES
Image: http://cnx.org/content/m44605/latest/Figure_22_02_07f.jpg

12. ARCHAEA
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70s ribosomes (same as eubacteria)
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Genes do not contain introns
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Some species have histone proteins
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Occupy extreme environments

13. Image: wikimedia.org

14. Image: ucmp.berkely.edu

15. XXXTREME ARCHAEA
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Halophiles
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- 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

16. DISTINGUISHING THE
THREE DOMAINS
Characteristic
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?
Archaea
Eubacteria
Eukaryota

17. DISTINGUISHING THE
THREE DOMAINS
Characteristic
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
A few
None
All
How many species
have histone
proteins?

18. DIVERSITY OF
EUBACTERIA

19. 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 filaments
Prefix “staphylo-”  form clusters
Ex. Staphylococcus form spherical clusters

20. 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

22. 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.

23. Image: bioart.co.uk/lux/vib.jpg

24. 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

25. DISTINGUISHING EUBACTERIA
- GRAM STAINING
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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

26. Image: http://pathmicro.med.sc.edu/fox/gram-st.jpg

27. GRAM- VS GRAM+

28. Image: http://4.bp.blogspot.com/gramposandneg.jpg

29. EXAMPLE OF GRAM
STAINED EUBACTERIA
Image: wikipedia.org