DIVERSITY!!! Bacteria and Archaea

eukaryotes prokaryotes bacteria archaea

Bacteria & Archaea All Prokaryotes First appeared on earth 3.4 bya (~1.7 by before eukarya) Incredibly numerous and diverse

Bacteria & Archaea: Trivia ~You have more bacterial cells in your body than your own cells: ______% of cells in your body are bacterial ~Estimated that the total # of bacteria (and archaea) alive today to be 5 x If lined up end to end would make a chain longer than Milky Way Galaxy (587,460,167,340,730 miles). ~Make up half of the biomass on earth *only 9-10,000 of them identified!* ~One ml of sea water contains about 1 million bacteria

Why should you care about prokaryotes? Bacteria keep you going – Mouth: Compete with pathogenic bacteria and yeast for food (ECOLOGY at work ) – Large intestine 100 billion Produce vitamins

Why should you care? Bioremediation: microorganisms return environment altered by contaminates back to original condition ‘seeding’

Why should you care? Biofuels: fuels produced from living organisms that contain over 80% renewable materials Scientists on quest to discover new bacteria that can use alternative electron acceptor or donor and convert it to a useable energy source (

Bacteria introduction activity One per person, but you can work in teams. 15 minutes

Why should you care? Nutrient Cycling: Without bacteria, you would have no nitrogen

Based on what you know about carbon, Where do you get your nitrogen (directly) from? A.The air you breathe (about 78% of atmosphere is N2) B.The plants you eat (which get it from the air) C.The plants you eat (which get it from the soil) D.The animals you eat (which get it from the air) E.The animals you eat (which get it from the plants)

Nitrogen makes up 78% of our atmosphere (as N 2 ), however, atmospheric nitrogen is: N 2 is triple-bonded N very stable difficult to cleave very stable and can’t be broken down to a usable form A.The air you breathe (about 78% of atmosphere is N2) B.The plants you eat (which get it from the air) D. The animals you eat (which get it from the air) Nitrogen from the air? So, plants and animals cannot use N 2 directly from the air

How does all of this unusable nitrogen get converted into something plants and animals can use? BACTERIA!

Lithotrophs Organisms that use inorganic compounds as their energy source Many microbes including Bacteria and Archaea

C. Nitrogen from eating plants which get it from soil and from E. eating animals that eat those plants We want to know: 1.How does the Nitrogen get to the soil? 2. Does all of that atmospheric nitrogen just go to waste b/c it can’t be directly taken in by plants and animals? Nitrogen from soil via plants and animals? YES

Nitrogen in soil comes from: Animals excreting ammonia => usable nitrogen Dead Plants and animals decompose=> biomolecules broken down to smaller molecules =>usable nitrogen

How do bacteria supply us with nitrogen? I.Nitrogen fixation II.Nitrification III.Denitrification Rhizobium: N-fixing bacteria that lives symbiotically in the roots of certain plants like beans and peas

(e.g. Rhizobium) bacteria also get organic N from dead matter, break it down to amino acids and nucleotides and then to NH 4 NH 4 still not usable by plants Atmospheric (inorganic) N 2 taken in by plants then converted to NH 4 by bacteria in plant root nodules or soil Nitrogen Fixation Nitrification NH 4 converted to NO 3 (only form plants can use) Nitrogen Cycle This NO 3 now taken up by plants (and used it to build amino acids) & converted back to atmospheric N 2 via denitrification

This is just one example of bacteria’s role in nutrient cycling Different species of bacteria cycles other inorganic molecules of carbon, phosphorous and sulfur similar to the nitrogen cycle This is not just a good example of how necessary Bacteria are but also a good example of their diversity (endless variety of metabolic pathways) Nitrogen fixation activity: one per person, but you may work in groups- due today

Why should you care? Taq polymerase – PCR reactions => amplify DNA from very small amount – Heat to denature DNA, copy, anneal Repeat – Copying DNA requires polymerase, a protein – High temperature environment denatures proteins. – NOT proteins adapted for high temperatures though!!!!

Speaking of “extremophiles”… Astounding diversity of prokaryotes – Habitat – Nutrient acquisition – Metabolism

Trivia: Habitat As a group, archaea and bacteria can live just about anywhere Acidic mud in yellowstone (pH 1) Glaciers, Arctic ocean (~1ºC) Hot Springs (100ºC) Salt Lakes (Salt conc. 10x higher than ocean) Soda lakes (pH 9-10)

Trivia: Nutrient acquisition Bacteria/Archea activity question 2. Prokaryotes Energy source Light Carbon Source CO2 Mode of nutriti on photoauto troph

Recall Aerobic Cell Respiration: C 6 H 12 O 6 + O 2 6 H e- donore- acceptor ADP + P i + energy  ATP energy CO 2 + By-products For most organisms, cell respiration means: Sugar is consumed: electron donor Oxygen is taken in: electron acceptor Fermentation & Aerobic and Anaerobic cellular respiration Trivia: Metabolism (cellular respiration and alternatives)

Bacteria & Archaea can use a wide variety of molecules as e- donors and e- acceptors in cell respiration (anaerobic respiration) The use of various molecules as electron donors and acceptors results in bacteria 1. “cleaning up each other’s mess” 2. Co-existing in one type of environment without competing for the same energy resources. Trivia: Metabolism

ACTIVITY: METABOLIC DIVERSITY TO ECOLOGICAL DIVERSITY