Presentation on theme: "Types of Heterotrophic Nutrition Methods of Feeding 1.Saprophytic Nutrition –feed on dead organic matter, get energy from it, and recycle it back into."— Presentation transcript:
Types of Heterotrophic Nutrition
Methods of Feeding 1.Saprophytic Nutrition –feed on dead organic matter, get energy from it, and recycle it back into the environment. decomposers. 2.Parasitism –organism (parasite) feeds off of another (host) at the expense of the host. 3.Predation –- organism (predator) hunts, kills, and eats another organism (prey). 4.Scavenging – feed on organisms killed by something else.
What are Bacteria? Bacteria are PROKARYOTES –The smallest known living cells They are found everywhere!! Bacteria on head of a pin Starr, 317 Bacteria in dental plaque microbeworld.org Did you know? There are over 80 species of bacteria in your mouth!
Obtaining Energy Autotrophs (make energy) –Photoautotrophs- capture energy from light Ex- cyabobacteria –Chemoautotrophs- obtain energy from chemical reactions with inorganic molecules (ammonia, hydrogen sulfide, nitrites, sulfur, Iron) make glucose using energy from chemical compounds Ex. Ocean vent bacteria
Obtaining Energy cont… Heterotrophs- most bacteria obtain their energy from organic molecules –These bacteria are often feeding in, on and around us… Some bacteria are photoheterotrophs –Capture sunlight and digest organic molecules
Releasing Energy Bacteria can use both cell respiration and fermentation Many bacteria have different oxygen requirements: –Obligate aerobes- must have oxygen for respiration –Facultative anaerobes- can function with or without oxygen –Obligate anaerobes- poisoned by oxygen (use fermentation)
Three basic shapes of Bacteria Spherical – coccus Rod – bacillus Coiled - spirillum Schraer, 633
Shapes of Bacteria
Coccus Spheres Cocci (plural) a variety of arrangements
Diplobacillus (paired) Bacillus Cylindrical or rod-shape Bacilli (plural) Variations in cell arrangement
Spirillium Spiral or “squiggle” shaped bacteria Vibrio Spirillum Spirochete
Simple Colonies Staphylo = clusters Strepto = chains Staphylococcus wisc.edu Diplo = double Diplococcus cat.cc.md.us Streptobacillus Bacterial colony shapes have specific names that are used as A prefix that combines with the name of their shape.
Some have flagella - made of rope-like proteins, not microtubules. Some slide on a slimy secretion. Many can form dormant cells called endospores to survive harsh conditions. Salmonella Streptomyces spores Many can MOVE
Bacterial Reproduction Bacterial cells reproduce asexually through fission which is the splitting of a cell into two new cells.
Bacterial Reproduction cont… Some bacteria utilize conjugation to exchange pieces of genetic information to increase variation –*Not considered sexual reproduction- not complete exchange of DNA, no offspring made
Bacterial Cells Their Structure
Structure of a Bacterial Cell Cell Wall Outside membrane- maintains cell structure May have cell wall + capsule (second wall) Protects the cell Eubacteria-composed of peptidoglycan, a polymer of sugars and amino acids Plasma Membrane Controls what enters and exits, selectively permeable phospholipid bilayer surrounding cell contains proteins that play a role in transport of ions, nutrients, and wastes Flagella (not found in all bacteria) tail-like structure used for locomotion
Structure of a Bacterial Cell Nucleoid region DNA is found in prokaryotes single double-stranded circular chromosome Contains all genetic information Plasmid (some bacteria) small circular chromosome carrying special genes may carry an antibiotic resistance gene Can be exchanged through conjugation Ribosomes site of protein synthesis (translation) Life Sciences-HHMI Outreach. Copyright 2008 President and Fellows of Harvard College.
Bacterial Structure Respiratory Enzymes –Use enzymes in the cytoplasm to undergo respiration Cytoplasm –Fluid filling cell
Two Kingdoms of Bacteria Kingdom Archaebacteria - “Ancient”, most primitive earliest known form of life - Kingdom Eubacteria - includes bacteria and cyanobacteria (blue-green) Fluorescent micrograph of an archaeon microbeworld.org
EUBACTERIA the “true” bacteria- more common
Cell Walls eubacterial cells have two different cell wall structures. A technique called gram staining can distinguish between: –Gram-positive: cell wall containing mainly peptidoglycan- stains purple –Gram-negative: bacterial cell has a second, outer layer of lipids and carbs- stains pink
Kingdom Eubacteria Photosynthetic – 2 groups 1) cyanobacteria (aerobes) –Have chlorophyll a and phycocyanin (blue) –Other colors, too –Most live in fresh water –Others live in salt water, soil and lichens Starr, 315 Nostoc Schraer, 637
More photosynthetics 2) green-sulfur and purple bacteria - anaerobic - colors range from pink to black - photosynthesize without water - make no oxygen - live in pond and sea mud
Cyanobacteria This is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond. Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria.
Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere.
Biologic Importance of Bacteria 1)Essential to nutrient cycling 2)Decomposers – in soil, inside animals 3) Enterobacteria – live inside us, break down waste, make vitamins vitamin K is essential to blood clot formation. 4)Process foods – cheese, yogurt etc.. 5)Some MAKE antibiotics (streptomyacin)
Bacterial uses cont. 6) Help with sewage treatment –Break down wastes 7) Can be utilized in genetic engineering, molecular research… –Insert foreign genes into new organism –Can be used to make specialized products like insulin 8) Indicate pollution levels –Provide visual clue to presence of pollution
9) Nitrogen Fixation –Still other Bacteria live on the roots of certain plants, converting atmospheric nitrogen into a usable form.
Some cause disease We call these “pathogens” Anthrax, as seen by Koch microbeworld.org But most are beneficial Bacteria ferment cheese Schraer, 641
Kingdom Archaebacteria Why a separate kingdom? Archae differ chemically from other bacteria. 1) cell wall - different amino acids and sugars. Eubacteria have peptidoglycan Archaebacteria have varied polysaccharides but not peptidoglycan. 2) unique membrane lipids 3) ribosomes 4) enzymes > 5) gene sequences... And MORE RNA polymerase
Archaebacteria Lack important carbohydrate found in cell wallsLack important carbohydrate found in cell walls Have different lipids in their cell membraneHave different lipids in their cell membrane Different types of ribosomesDifferent types of ribosomes Very different gene sequencesVery different gene sequences Archaebacteria can live in extremely harsh environmentsArchaebacteria can live in extremely harsh environments They do not require oxygen and can live in extremely salty environments as well as extremely hot environments.They do not require oxygen and can live in extremely salty environments as well as extremely hot environments.
Archae are extremophiles Live in habitats like early earth Too harsh for most organisms 1) methanogens – decomposers, live in intestines, swamps & bogs sewage treatment 2) Halophiles – “love salt” Great Salt Lake, Dead Sea 3) Thermophiles – hot springs, geysers 4) Acidophiles – acidic environments Starr,635
Archaea, the “extremophiles” methanogens, thermophiles, halophiles
Nitrogen-fixing Fix nitrogen in special cells called heterocysts Chemosynthetic make glucose using energy from chemical compounds **Mostly archae Starr, 745 Legume roots – nodules contain nitrogen-fixing bacteria Tube worms at ocean vent Fed by chemoautotrophs Starr, 314 Eubacteria and Archaebacteria