Option F – Microbes and Biotechnology

The three Domains of Life: Archaea Prokaryotes Eukaryotes This distinction was made using rRNA – Ribosomal RNA! F.1.1 F.1.2 Why do we need to differentiate organisms into three domains?

BACTERIAARCHAEAEUKARYOTA HISTONES ASSOCIATED WITH DNA AbsentProteins similar to histones bond to DNA Present PRESENCE OF INTRONS Rare or absentPresent 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 filaments Prefix “ staphylo-”  form clusters Ex: 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 Life Source: 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?

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. 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.1.6 Vibrio fischeri a Gram - negative bacterium found in sea water that is able to bioluminiscence once a population reaches a certain density

Gram-positive vs Gram-negative What’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.1.8 Viral 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 Inquiry You 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: Domain Nutrition Locomotion Cell Wall? Gram +/- Chloroplasts? Cilia/Flagella Interaction with humans? Once you have orally checked off, add your data to the class set on the SMARTBoard. F.1.9

Genus Saccharomyces AmoebaPlasmodium Paramecium Euglena Chlorella NutritionHeterotrophic: 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 Photohetero trophic: they possess chloroplasts and take organic matter by endocytosis Autotrophic: they possess chloroplasts and synthesize organic compounds by photosynthe sis LocomotionNon- motileMove 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 wallMade of chitinabsent Made of cellulose Human Interaction? Beer, WineFresh Water Environments Infections - MalariaMarine Environments Alertness to pollution Used in Medicine Comparing Microbes F.1.9