Overarching Theme – Unity and Diversity MICROORGANISMS – How do the structures and functions of Eubacteria, Archaea and Protists

show similarities and differences? Big Idea – Even though there is such great diversity among microorganisms,

ranging from habitat, the type of cell wall it has, and how it obtains its food, there is a strong similarity in the types of structures many microorganisms have.

PROKARYOTES = before a nucleusSome thoughts on Unity and Diversity

“The stunning variety of living systems belies a striking similarity. The common use of DNA and the genetic code by all organisms underlies one of the most powerful discoveries of the past century—namely, that organisms are remarkably uniform at the molecular level. All organisms are built from similar molecular components distinguishable by relatively minor variations. This uniformity reveals that all organisms on Earth have arisen from a common ancestor. A core of essential biochemical processes, common to all organisms, appeared early in the evolution of life. The diversity of life in the modern world has been generated by evolutionary processes acting on these core processes through millions or even billions of years.” (Berg JM, Tymoczko JL, Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002. Section 1.2, Biochemical Unity Underlies Biological Diversity. Available from: http://www.ncbi.nlm.nih.gov/books/NBK22462/)

“The small size, ubiquity, metabolic versatility and flexibility, and genetic plasticity (horizontal transfer) of microbes allow them to tolerate and quickly adapt to unfavorable and/or changing environmental conditions. Prokaryotes are endowed with sophisticated cellular envelopes that contain molecules not found elsewhere in the biological world. Although prokaryotic cells lack the organelles that characterize their eukaryotic counterparts, their interiors are surprisingly complex. Prokaryotes sense their environment and respond as individual cells to specific environmental challenges; but prokaryotes also act cooperatively, displaying communal activities.” (Kluyver, A.J. 1959: Unity and diversity in the metabolism of micro-organisms. In: Albert Jan Kluyver, His Life and Work: Biographical Memoranda, SelectedPapers, Bibliography and Addenda. A. F. Kamp, J. W., M. La Reviére, and W. Verhoeven, eds., NorthHolland Pub. Co., Amsterdam, 186–210.)

Unity – What characteristics do all Prokaryotes share?- are micro-organisms, living cells that can only be seen under a microscope- unicellular, but some join into colonies of individual cells- three basic shapes

i) spherical (coccus) forms, may be single or in pairs (diplococci), in chains (streptococci) or in clumps (staphylococci), e.g. bacterial pneumonia, scarlet fever, boilsii) rod-shaped (bacillus) forms, may be single, in pairs (diplobacillus) or in chains (streptobacilli), may have a gelatinous covering, e.g. tuberculosis, cholera, typhoid, tetanusiii) spiral (spirilla) forms, rarely in clusters or colonies

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- lack a nucleus and other membrane-bound organelles, but have DNA condensed into a nucleoid (though usually only 1 chromosome and little loops called plasmids) and ribosomes - SOME have flagella or pili for movement and/or slime capsule for protection and attachment- have a cell wall that is very strong and helps keep their shape in hypotonic environments- need to fulfill all requirements of life; made of cells, grow and develop, respond to stimuli, reproduce, obtain energy, and change over time – how they perform these tasks is incredibly diverse- likely were the first living things on Earth

Taxonomy- divided into two Domains

i) Eubacteria - the larger of the two groups of prokaryotes- most diverse group of organisms on Earth- found everywhere on Earth, from polar ice to deep oceans to rainforest soil- cell walls contain peptidoglycan, a strong carbohydrateii) Archaea - live in ‘extreme’ environments; no oxygen, high salt, no light, high temperature (e.g. hydrothermal vents near mid ocean ridges)- many are obligate anaerobes (=cannot live in presence of O2) that use CO2 during respiration to obtain energy and give off methane gas as a waste product- lack peptidoglycan in cell walls- DNA sequences of key genes are more like those of eukaryotes than eubacteria

Diversity – What different strategies have prokaryotes developed to fulfill the requirements of life?Growth and Reproduction, Baby!-Four conditions needed for bacterial growth

1) Suitable temperatures, usually 25-38 degrees Celsius, though some Archaea can live anywhere between 0-300 degrees Fahrenheit! - when we have a fever, this is our body’s way of making it too hot for bacteria to survive2) Moisture3) Low light, since they have very little protection from UV damage4) Suitable food source

-spore formation is sometimes used in unfavourable conditions, tetanus and anthrax are examples, -the bacterium produces an extremely thick cell wall to enclose its DNA and cytoplasm

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-it can survive in this dormant condition for years, spores are not killed by normal disinfectant methods, but may be killed by pressurized steam (autoclave)-they reproduce asexually, usually by binary fission (essentially splitting in 2)-in ideal conditions (see above), this can happen every 15-20 minutes (that means 1 becomes approx. 260,000 in 6 hours!)-some prokaryotes exhibit a form of reproduction called conjugation, during which some genetic material is exchanged to ensure genetic diversity in a population -see diagram – A) conjugation tube/bridge forms between donor and recipient

B) donor DNA is replicated C) replicated DNA is transferred to recipient

D) conjugation tube/bridge disappears: segments of replicated DNA incorporated into recipient’s chromosomesE) when recipient cell undergoes binary fission, passes on new genetic combinations to daughter cells

Learning Activity – Bacterial Populations sheet, Bacterial Growth Lab

Methods of Obtaining Energy - No characteristic of prokaryotes shows their diversity better!i) Heterotrophs-Most prokaryotes obtain food from other organisms or organic material-parasites – live on/in a host and obtain food from it, e.g. E. coli lives on sugars in the human digestive tract-saprophytes (decomposers) – obtain food from dead or decaying matter, e.g. soil bacteria, which are very important to us because they make sure nutrients are recycledii) Autotrophs

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-can make their own food and ATP -photoautotrophs carry out photosynthesis (e.g. blue-green ‘algae’ = cyanobacteria)-chemoautotrophs breakdown and release inorganic compounds in process of chemosynthesis (e.g. Methanococcus lives deep in the ocean near hydrothermal vents and uses methane to synthesize food)

Respiration-some need oxygen to live and are called obligate aerobes (= “needing oxygen”)-some CANNOT exist in the presence of oxygen and are called obligate anaerobes (=needing no oxygen) e.g. Clostridium botulinum that can cause botulism, a potentially deadly form of food poisoning and are injected into cells to selectively paralyze muscles to temporarily relieve muscle function a.k.a. Botox!-most are fine with or without oxygen, when O2 is present, these facultative anaerobes (=can work with no oxygen) use it to respire, but when no O2 is available, the bacteria undergo fermentation

What Does This Have To Do With Me? Bacteria Can Cause Disease!-happens in one of two ways; either bacteria damage tissues of infected organism directly or they release toxins that harm the body.

-Methods of bacterial infectioni) contaminated food and water e.g. Coliform bacteria can cause dysenteryii) air-borne droplets, e.g. Bacillus anthracis (anthrax)iii) direct contact with open wounds or sores, e.g. many STD’s such as Neisseria gonorrhea and

Spirilla spp. (syphilis)iv) wound infectionsv) insect carriers, e.g. flies walk on rotten things and then their feet transfer bacteria to you

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Learning Activity – Food Poisoning Case Study

Some Bacteria are Helpful Thoughi) like dairy products? used to make cheese and yogurt, bacteria coagulate milk protein and

yield distinctive flavoursii) wine, beer and spirits made through fermentationiii) also, Kim chi, soy sauce, tofu, miso, sauerkraut…iv) some can be used to clean-up oil spills, others remove waste products and poisons from

water

Yuck! Kill them! Kill them!-But remember, all are not bad.-We can prevent infection through first line of defense (skin, sweat, tears…) and second line of defense (WBC and antibodies, some actually disintegrate bacterial walls, while others neutralize bacterial toxins)-also body creates fevers to try to kill bacteria-can also take antibiotics prescribed by doctor-food preservationi) sterilization by heating or treating with chemicals to kill bacteria (canning, pickling, cooking…)ii) cold storage, bacteria become dormant and cannot multiplyiii) storing in airtight containers, since most forms need O2 iv) pasteurization, heat to 140oF for 30 min., then cool quickly, kills most harmful forms

Is it that easy?-not quite, bacteria can develop resistance to antibioticsi) antibiotics (in blood, soap, medicine, etc.) kill MOST bacterial cellsii) any left are usually engulfed by WBC or destroyed by antibodies, BUT some may surviveiii) those that are left have some genetic mutation that has resisted antibiotics, antibodies, etc. so they are ‘more fit’ and go on to reproduce offspring that will infect other organismsiv) since these bacteria are resistant to further treatment by the same antibiotic, stronger/different antibiotics must be used, eventually creates (by accidental selection) a superbug

EUKARYOTES - Eu=good, Karyon = nut/kernelUnity - What characteristics do all Eukaryotes share? -in terms of numbers, there are far fewer eukaryotic than prokaryotic organisms, but are generally larger in size -contain a nucleus and other structures (organelles) enclosed within membranes-cell division occurs via mitosis or meiosis (required for sexual reproduction)-includes all members of Domain Eukarya (plants, animals, fungi and protists)

KINGDOM PROTISTA – Protistos = the very firstUnity – What characteristics do all Protists share?

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-unicellular eukaryotes that either exist as independent cells, or if they occur in colonies, do not show differentiation into tissues (i.e. only cellular level of organization) -can only be seen under a microscope-respiration is by diffusion (gases pass through cell membrane)-were first eukaryotic organisms to appear on Earth, mitochondria and chloroplasts found in eukaryotic cells may have descended from aerobic and photosynthetic prokaryotes that lived in larger cells in a symbiotic relationship

Diversity – What different strategies have Protists developed to fulfill the requirements of life?Taxonomy- this kingdom contains ‘leftovers’ of Animalia, Plantae and Fungi, this is why this kingdom is so

diverse- are three major divisions within this kingdom, defined by mode of obtaining food – Ingestive,

Photosynthetic and Absorptive- molecular information has been used to redefine this group in modern taxonomy as diverse and

often distantly related phyla; protists are now considered to mean a group of diverse phyla that are not closely related through evolution and have different life cycles, trophic levels, modes of locomotion, and cellular structures

- some Biologists classify algae as Protists- it is likely that classification systems for Protists will change at some point in the future, dividing the

one Protist Kingdom into several smaller ones

Ingestive Protists (Animal-Like)General Characteristics-most have ability to move (exception are Sporozoa)-lack cell walls-sometimes called protozoa=first animals-most are aquatic, living in fresh or saltwater at least part of their life-cycle-reproduction usually asexual by binary fission, except in adverse conditions such as starvation, heat stress or lack of O2

-four main phylao Zoomastigina – e.g Giardia intestinaliso Ciliophora –e.g. Paramecium spp.o Sarcodinia – e.g. Amoeba spp.o Sporozoa – e.g. Plasmodium falciparum

1. Zoomastiginia-move using a flagellum, so are called flagellates-able to absorb food through their cell membrane-live in lakes and ponds, also can be found on/in a host, so these forms are considered to be parasitic2. Ciliaphora-have hair-like structures called cilia all over body, these are synchronized for movement, like oars-movement is by trial and error-sometimes cilia used for attachment to a substrate

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-reproduction is usually asexual by binary fission, but can undergo conjugation, which is not really sexual reproduction since no new cells are made, however genetic material is exchanged and this helps to ensure genetic diversity of the species-found in both fresh and marine water environments, but in quiet, not turbulent water-Example = Paramecium (genus)-observe the following specialized cell structures on diagram below (label the letters, from top to bottom)A. Pellicle – flexible and elasticB. Contractile Vacuole – to get rid of excess water C. Feeder/Radiating Canal – leads into contractile vacuole, so that water can collect D. Cilia –small hairs, synchronized for movementE. Trichocysts – contain barbed threads that may be fired in defense or attackF. Oral Groove – line with beating cilia to draw food in G. Micronucleus – supervises reproductionH. Macronucleus – oversees all metabolic processesI. Cell Mouth – food enters here!

J. Gullet – vacuoles form hereK. Anal Pore – wastes evacuated L. Food Vacuole Forming – food particles trapped in vacuole and pinch off into cytoplasmM. Food Vacuole Circulating– as it travels around inside (see arrows), fuse with lysosomes with digestive enzymes, food is digested, and cell obtains nutrients

N. Ectoplasm – thin and clearO. Endoplasm – thick and granular

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3. Sarcodinia-most have an extremely flexible plasma membrane that is necessary for movement-move using pseudopods (= false feet), these form fingerlike projections of cytoplasm that help with movement and food capture-capture food by surrounding it with their pseudopods and taking it inside to form food vacuoles

-wastes excreted in same way, but in reverse!-some have shells (e.g. foraminiferans) but still use pseudopods for movement and food capture-in unfavourable conditions they can form a cyst, essential cell components become packed into a very tough little ball that will ‘hatch’ out in more suitable conditionsExample = Amoeba (Ameba) (genus)- observe the following specialized cell structures on diagram below (label the letters clockwise, starting a 2 o’clock)A. Cytoplasm being pushed into pseudopod (creating fingerlike projection)B. Food Vacuoles – temporarily store food particles and then digested rapidly C. Mitochondrion – site of cellular respirationD. Pseudopod – temporary projection of cytoplasm

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E. Plasma Membrane – fluid cell membrane to allow shape-shifting, made of endoplasm (very fluid outer membrane) and ectoplasm (inner, thickened cytoplasm)F. Nucleus – controls cell activitiesG. Nucleolus – where ribosomes are madeH. Contractile Vacuole – gets rid of excess water

4. Sporozoa- lack independent locomotion- exclusively parasitic- have very complex life cycles- example = Plasmodium falciparum, which causes malaria- totally dependent on hosts for food, locomotion, respiration, etc.

Learning Activity – Malaria Life-Cycle Sheet

Photosynthetic Protists (Plant-Like)General Characteristics-autotrophic, all possess photosynthetic pigments -most live as producers in aquatic habitats-3 main phyla

o Euglenophyta – e.g. Euglena spp.o Bacillariophyta – e.g. Diatomso Pyrrophyta – e.g. Dinoflagellates

1. Euglenophyta- have flagellum for locomotion, so are called flagellates

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-since they can move, are closely related to ingestive protists, but also can make own food so also related to photosynthetic protists-can live as heterotrophs and absorb food through cell membrane or mouth when needed-have an eyespot = an area that is light sensitive, this is important in photosynthesis as it needs to be able to find the brightest, sunniest spot in its environment to successfully photosynthesize-no cell wall, but has an outer coat with contractile fibres called a pellicle-Example = Euglena (genus)-observe the following specialized cell structures on diagram below (label the letters, from top to bottom)A. Flagellum – at anterior (head) end of body, whips back and forth moving the organism forwardB. Mouth – where food enters body if habitat has low lightC. Eyespot – usually red, helps organism move to area of lightD. Gullet – where both flagella are attachedE. Contractile Vacuole – formed by small water-filled vesicles fusing together, removes excess water to prevent lysisF. Paramylum Granules – starch storage for energy when food sources and light are lowG. Ectoplasm – thin, gelatinous layer of cytoplasmH. Chloroplast – green, site of photosynthesisI. Endoplasm – thin, granular, inner cytoplasmI. Nucleus – controls all cell activitiesJ. Myoneme – fibres that act like muscles, allowing organism to contractK. Pellicle – cell membrane, flexible, grooved and fibrous, permits absorption and diffusion, is tough to resist osmotic pressure (prevents lysis)

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2. Bacillariophyta -most species are diatoms-silica (main element in glass) cell wall with many pores-live in fresh and marine environments-are the most abundant plant-like protists-are enclosed within two valves (shells), a top and a bottom that fit snugly together-store food as oil rather than carbohydrate, enhances their buoyancy so tend to float close to surface of water, which helps with capturing light for photosynthesis-are used in toothpastes and polishing agents due to their silica shells

3. Pyrrophyta-dinoflagellates-usually move using two flagella, one wrapped around its middle and the other trailing behind like a tail-some are surrounded by thick plates of cellulose that serve as protection-are a major component of ocean phytoplankton-many species can produce bioluminescence, when agitated by the movement of a boat oar or person swimming they give off a blueish light, causing the dark water around them to shimmer, hence their name, Pyrrophyta, which means ‘fire plants’

Learning Activity – Protist Microscope Lab

Absorptive Protists (Fungi-Like)General Characteristics-commonly called Slime Molds-are heterotrophs that live on and breakdown dead or decaying organic matter and absorb nutrients into their cells-lack chitin cell walls of true fungi-play key role in recycling organic material-go through two stages in life cycle-reproduce by spores borne on fruiting bodies-slime mold masses not microscopic, can be several metres in diameter-2 main phyla

o Acrasiomycota = cellularo Myxomycota = acellular

1. Acrasiomycota

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-begin their life as amoeba-like creatures-spend most of life in ‘feeding stage’ as individual free-living cells that live in soil and absorb food-when food supply runs low, they release a chemical that causes them to group together in large masses and begin to function as a single organism-they look like slime but can actually move several centimetres at a time (slowly!) looking for food-the slimy mass forms a reproductive structure called a fruiting body that produces spores by mitosis-these spores land in nearby areas and grow into individual amoeba like cells, thus repeating the cycle

2. Myxomycota-begin life as flagellated cells that fuse and develop into amoeba-like cells-‘feeding stage’ occurs when amoeba-like cells aggregate (due to chemical signal) together as a large multinucleated mass called a plasmodium = thousands of nuclei enclosed in a single cell membrane with no internal cell walls-when food or moisture become limited, fruiting bodies spring from the plasmodium (note – do not confuse the structure plasmodium with Plasmodium falciparum, the protist species that causes malaria) and produce spores that go on to germinate into flagellated cells, thus repeating the cycle-what similarities does this life cycle have to others you have learned?

Ecological Role of ProtistsHelpful-vital to food chains-most of world’s photosynthesis performed by photosynthetic aquatic protists, provide much of O2 in Earth’s atmosphere-many mutualistic relationships, e.g. a type of Zoomastigina lives in termite digestive systems, helps them digest wood and obtain nutrients

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-slime molds play vital role as decomposers in ecosystems, release nutrients so that they can be recycledHarmful-some are disease causing, e.g. Plasmodium falciparum that causes malaria, Giardia intestinalis that causes giardia or ‘beaver fever’ (=intestinal distress after consuming untreated water containing feces from vertebrates), tse tse fly carries Zoomastigina species Trypanosome which causes sleeping sickness,-some Pyrrophyta species can cause red tide when they mass in large numbers and create lethal levels of toxins, filter feeders such as mollusks ingest toxins and store in muscle tissue. Can cause death and paralysis in humans if this shellfish is consumed.

Confirm Your Learning – Pathogenic Microorganisms Project, due ________________

Connections to Biological Theme – Describe three ways that prokaryotes show unity and three ways they show diversity. Name three ways that eukaryotes show unity and three ways they show diversity.__________________________________________________________________________________________Prokaryotes Unity- Three basic shapes (spherical, rod-shaped, spiral)- No nucleus or membrane-bound organelles- cell wall- similar reproduction through binary fissionProkaryotes Diversity- Variety of ways to get food- Variety of ways to respire- Cause variety of different diseasesEukaryotes Unity- Nucleus and membrane-bound organelles- Respiration by diffusion- Unicellular but some form colonies- Only cellular level of organizationEukaryotes Diversity- Different ways to obtain food- Many different cellular structures- Exist in many different trophic levels

Prokaryotes sense their environment and respond as individual cells to specific environmental challenges. Use evidence from what you have learned to back up or refute this statement. Explain your reasoning.

-endospore formation-type of reproduction depending on whether conditions are suitable or not

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