Microorganisms Microbes • too small to be seen with the naked eye • aggregations or colonies can be seen without the aid of a microscope.
Download ReportTranscript Microorganisms Microbes • too small to be seen with the naked eye • aggregations or colonies can be seen without the aid of a microscope.
Microorganisms Microbes • too small to be seen with the naked eye • aggregations or colonies can be seen without the aid of a microscope Microbes • are found almost anywhere • are more abundant than any other life form • they are forms on which all others depend. Recycle elements required for life • N - Nitrogen • O - Oxygen • P - Phosphorus • S - Sulfur • C - Carbon Microbes produce • food • fuel • air 4 major categories • bacteria • fungi • protists • viruses Pathogens • disease causing agents • AIDS - Acquired Immune Deficiency Syndrome • Botulism - food poisoning • Tuberculosis • Polio Pathogens • Typhoid Fever Syphilis Disease • Microbes cause disease by directly damaging tissues and weakening bodily functions or by producing toxins that do. Pathogenic microbes • the proportion of pathogenic microbes on earth is very small Producers • produce carbohydrates • break down starch into sugar • convert sugars into alcohol Water Dwelling microbes • algae and bacteria • largest producers of carbon containing compounds through photosynthesis Some microbes • are unable to take in Carbon Dioxide from the air. • They get Carbon from bicarbonate in the water Ion • an atom that carries a positive (+) or a negative (-) charge • carries the charge because it has gained or lost one or more electrons Microbes use CHO’s (carbohydrates) • synthesized during photosynthesis (Ps) to make cell structures and as an energy source • Provide food for larger organisms Single Celled Fungi • Yeasts • Producers in wine making, bread baking or beer brewing. • Convert sugar to alcohol in fermentation process Cheese Making • bacteria convert lactose (milk sugar) to lactic acid Contribute to production • of food and other substances by their enzymes Enzymes • organic molecules that speed up biochemical reactions without being used up or becoming part of the end product. • A catalyst - causes a reaction to take place Examples • foods • medicines • vitamins • leather processing • textile production Decomposers and Recyclers • world’s greatest recyclers • Keep elements like C and N cycling through the environment • Used to treat sewage, clean up toxic wastes, processing Recyclers • more than one type of bacterium is needed to convert atmospheric N into a form useable by plants. • Requires three different chemical reactions. Production through decomposition • Methane - decomposition of organic matter • Methanogens - swampy areas, land fills, digestive tract of ruminants. Production through decomposition • Linen fabric is made from flax stems • Stems are immersed in water • Bacterium digests pectin that makes the stalks stiff Linen Fabric Production • remainder is washed dried and spun into thread and then woven into fabric Basic features of MO’s (microorganisms) • 4 major groups –bacteria, fungi, protists, viruses • Viruses are not made up of cells and are not considered organisms by many Bacteria, fungi and protists • have a cellular structure, a membrane surrounding cytoplasm Protists • have an inner compartment nucleus • DNA in non circular chromosomes • unicellular or multicellular • protozoans, algae, others Fungi • have cellular structure • non circular chromosomes • in fungi with many cells, walls between cells are sometimes not complete • cytoplasm and nuclei can Fungi • have cellular structure • non circular chromosomes • in fungi with many cells, walls between cells are sometimes not complete Fungi • cytoplasm and nuclei can stream from one cell to another within slender filaments of cells called hyphae Yeasts • unicellular Molds • have many cells Fungi • visible to the naked eye –mushrooms –bracts –puffballs –toadstools Viruses • not cellular • particles made up of nucleic acid and protein • Include short length of DNA or RNA - never both! Viruses • On their own they cannot reproduce at all • Inject their nucleic acid into a host cell Viruses • Injected DNA or RNA tricks host cell into using the viruses chemical instructions to make substances needed for the virus to reproduce Viruses • Host cell is damaged when newly reproduced virus particles break out of cell (lyse) What does it take to keep a microbe alive? • Lots of variation in environmental and nutritional condition requirements Nutritional needs • energy sources • basic elements to make and replace cell structures Heterotrophs • organic compounds to meet energy needs • Carbon source to make own organic molecules • get energy from sugars, starches, fats and other organic Saprobes • live in soil, get nutrients from dead organic matter • Clostridium botulinum botulism, food poisoning Autotrophs • build their own organic compounds if they have an available source of inorganic compounds Phototrophs • generate their own food using sunlight and inorganics such as carbon dioxide Chemotrophs • don’t require sun • get energy from carbon dioxide, salts, water and others Nitrosomonas bacteria • live in soil • use ammonia (NH4) as energy hetero, chemo and phototrophs • use energy from the environment • light and heat energy from the sun • energy stored in chemical bonds or organic or inorganic Six major elements in cells • C - Carbon • H - Hydrogen • N - Nitrogen • O - Oxygen • P - Phosphorus • S - Sulfur Also • K- potassium • Ca - Calcium • Fe - Iron • Na - Sodium Trace elements • Co - Cobalt • Zn - Zinc • Mo - Molybdenum • Cu - Copper • Mn - Manganese • Si - Silicon hetero, chemo, and phototrophs • some require organic compounds that they cannot make themselves • must be added to culture in isolation - called growth factors • Vitamins Microbial nutrition in the lab • hardened gel - called agar • nutrients are added to the agar • called growth medium Pure Cultures • Grow only one kind of microbe • Must use aseptic technique to avoid contaminating the culture Mixed cultures • may be grown on selective media • nutritious to some and not to others • allows researchers to isolate a certain species of microbe Environmental conditions for microbial growth • Oxygen - require Oxygen aerobic • some microbes live in Oxygen poor environment - anaerobic Anaerobic processes • fermentation • O2 atoms in compounds are rearranged and made available to microbes Anaerobes • made up of molecules containing O2 but don’t produce free or gaseous O2 Anaerobes • free oxygen may be toxic pH • favorable range - 6-8 • acidophillic - acid loving used in mining operations. • Oxidize Cu, Fe and other metal sulfides in the process of pulling out the ore Temperature • 37 degrees C (98 degrees F) • some can survive a wide range of temps ranging from 32 degrees F to 212 degrees F Moisture • dissolve minerals, ions, gases and organic compounds Moisture • in extremely dry conditions microbes form spores that hold the genetic information and some cytoplasm. Spores • when moisture is added the spore breaks down and bacteria resume their normal activity Salt concentrations • most microbes can’t survive in high salt or sugar concentrations Microbe sex • or - how microbes reproduce • process is known as binary fission Binary fission • increase in size, extend cell wall material down center and divide in two. Speed of reproduction • in 24 hours some species of bacteria can go from one cell to 16,777,216 cells Single celled protists • have a more difficult reproductive process • DNA in nucleus is fist replicated then divided into 2 identical sets (mitosis) continued • cytoplasm of cell then divides to form 2 identical daughter cells. Fungi • reproduce by a number of methods • yeasts - budding - cytoplasm pinches off on one side of cell to form a new cell • or fuses with another cell Fungi • after fusing with a cell, nuclei fuse and divide to form spores when released from the cell Yeast • spores become cells on their own Many celled fungi • hyphae or filaments fuse to form sporagia • cases in which nuclei from 2 parent molds excahange pieces of chromosomes • a type of sexual reproduction Microbial populations • can and do change over time • bacterial populations adapt to changes in the environment Mutations • change in DNA • alteration of base sequence • occur spontaneously Genetic recombination • exchanging or recombining genetic information • two bacterial cells become connected by a thin strand of cell material called a pilus Genetic recombination • DNA can travel from one microbe to another • gene enters a microbe that did not initially have it