Q What are cell? A: Cells are basic units of life that cannot ne seen with naked eye.
Microorganisms Microbes too small to be seen with the naked eye aggregations or colonies can be seen...
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Transcript of Microorganisms Microbes too small to be seen with the naked eye aggregations or colonies can be seen...
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 FeverSyphilis
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
• Replenish Oxygen supply
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 materials
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 microbiologists.
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 resemble fungi
Fungi
• have cellular structure
• non circular chromosomes
• in fungi with many cells, walls between cells are sometimes not complete
• cytoplasm and nuclei can stream from one cell to another within slender filaments of cells called hyphae
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 compounds
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 compounds
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