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