Size of Living Things
1 m = 100 cm = 1,000mm = 1,000,000 µm = 1,000,000,000nm
1mm = 1000 µm = 1000000nm
1 µm = 1000nm Click link for an interactive
“Size of Microscopic Things”
animation on Cells Alive. From the Virtual Microbiology Classroom on ScienceProfOnline.com
Two Basic Types of Cells
EukaryoteProkaryote
Images: Prokaryotic cell diagram & Eukaryotic cell diagram, M. RuizFrom the Virtual Microbiology Classroom on ScienceProfOnline.com
Separates the cell from its environment.
Phospholipid molecules oriented so that hydrophilic water-loving heads directed outward and hydrophobic water-hating tails directed inward.
Proteins embedded in two layers of lipids (lipid bilayer).
Membrane is semi-permeable.
Plasma Membrane
From the Virtual Microbiology Classroom on ScienceProfOnline.comDiferencias de las archaeas
Prokaryotes - Cell Wall Gram-Positive & Gram-Negative
Images: Sources UnknownFrom the Virtual Microbiology Classroom on ScienceProfOnline.com
From the peptidoglycan inwards all bacteria are very similar. Going further out, the bacterial world divides into two major classes (plus a couple of odd types). These are:
Gram Positive Gram Negative
Prokaryotes - Cell Wall
Images: Staph, Gram Stain, SPO Microbiology Images, T. Port; E coli, Y tambeFrom the Virtual Microbiology Classroom on ScienceProfOnline.com
Prokaryotes – Plasma Membrane as a Barrier
Passive Diffusion
Is the diffusion of water across a semi-permeable membrane.
Environment surrounding cells may contain amounts of dissolved substances (solutes) that are…
- equal to- less than
- greater than
…those found within the cell.
Images: Osmosis animation; Osmosis with RBCs, M. Ruiz
CELL
Plasma membrane
Liquid environment
outside the cell.
Liquid environment
inside the cell.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Plasma Membrane as a Barrier
ACTIVE TRANSPORT
• How most molecules move across the plasma membrane.
• Analogous to a pump moving water uphill.
• Types of active transport are classified by type of energy used to drive molecules across membranes.
• ATP Driven Active TransportEnergy from adenosine triphosphate (ATP) drives substances across the plasma membrane with the aid of carrier molecules.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Prokaryote Genetics
Nucleoid
•Region of cytoplasm where prokaryote’s genome is located.
•Usually a singular, circular chromosome.
Plasmid
•Small extra piece of chromosome/genetic material.
•5 - 100 genes
•Not critical to everyday functions.
•Can provide genetic information to promote:
- Antibiotic resistance
- Virulence factors (molecules produced by pathogen that
specifically influence host's function to allow the pathogen to thrive)
- Promote conjugation (transfer of genetic material between
bacteria through cell- to-cell contact)
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Prokaryotes Cell Division
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Prokaryotes - Endospores
Dormant, tough, non-reproductive structure produced by small number of bacteria.
Resistant to radiation, desiccation, lysozyme, temperature, starvation, and chemical disinfectants.
Endospores are commonly found in soil and water, where they may survive for very long periods of time.
Image: Bacillus subtilis, SPO Science Image Library, Endospore stain from Dr. Ronald E. Hurlbert,
Microbiology 101 lab manualFrom the Virtual Microbiology Classroom on ScienceProfOnline.com
An endospore stained bacterial smear of Bacillus subtilis showing endospores as green
and vegetative cells as red.
Cell Shapes (Morphology)
Most bacteria are classifies according to shape:
1. bacillus = rod-shaped
2. coccus = spherical
3. Spiral Shaped
a. spirillum = spiral with rigid cell wall, flagella
b. spirochete = spiral with flexible cell wall, axial filament
There are many more shapes beyond these basic ones. A few examples:
– Coccobacilli = elongated coccal form
– Filamentous = bacilli that occur in long threads
– Vibrios = short, slightly curved rods
– Fusiform = bacilli with tapered ends
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Acidithiobacillus
Archaea
Leptospirillum
Sulfobacillus
Crecimiento Microbiano
• Refers to increase in the number of microbes (reproduction) rather than an increase in size of the microbe.
• Result of microbial growth is the colony = aggregation of cells arising from single parent cell.
• The time required for growth and reproduction is known as the doubling or generation time.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Doubling Time in Cell Count From Binary Fission
Generation Cell Number Count
0 11 22 43 84 165 3210 1,02420 1,048,576
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Bacterial Population Growth Curve
Image: Bacterial growth phases, Michal KomorniczakFrom the Virtual Microbiology Classroom on ScienceProfOnline.com
Generation Time Under Optimal Conditions
Organism Generation Time
Bacillus cereus 28 min
Escherichia coli 12.5 min
Staphylococcus aureus (causes many types of infections) 27-30 min
Acidithiobacillus ferrooxidans 10-12 hrs
Archaea (Acidianus, Sulfolobus, Metallosphaera) 10-30 hrs
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Microbial Nutrition
• Organisms use a variety of nutrients for:– their energy needs – to build organic molecules & cellular
structures.
• Most common nutrients contain necessary elements:
– Carbon– Oxygen– Nitrogen– Hydrogen
• These 4 elements make up 95% of dry weight of bacterium.
• The other 5% is composed of Calcium, Copper, Iron, Magnesium, Manganese, Phosphorus and Iron.
• Other elements that are needed are ___________ __________.
• These elements are needed in extremely small amounts, can be obtained through water intake.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Factors Influencing Microbial Growth
•Nutrition
•Oxygen
•Temperature
•pH
•Osmotic Pressure
From the Virtual Microbiology Classroom on ScienceProfOnline.com
La vida en mundo desde 3.8 Ba
18Los tres dominiones de vida
Microbes & Temperature
Proteins Three-dimensional shape because of the
temperature sensitive hydrogen bonds.
These bonds will usually break at higher temperatures, and protein become unfolded.
Denatured proteins lose function.
Cell Membrane
Also temperature sensitive.
Become brittle if temperature is too low.
If temperature too high, lipids will be more liquid in form.
Outside membrane cannot preserve the integrity of the cell and it will disintegrate.
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Categories of Microbes Based on Temperature Range
Ambientes frios
Transporte de equipo a Glaciar de Fremont
Taladro de hielo con equipo termal
Glaciar de Fremont
Meet the Microbe!
Psychrophilic Alga: Chlamydomonas nivalis
Largest Image: Watermelon snow, Will Beback
From the Virtual Microbiology Classroom on ScienceProfOnline.com
Ambientes de alto calor
Mt. Soufriere, Montserrat
Calcite Springs, Yellowstone
Obsidian Pool, Yellowstone
Realgar Springs, Yellowstone
Ambientes de bajo pH
Mina Morenci, ArizonaMina Blackbird, Idaho
Mina Parys, Gales Roaring Mountain, Yellowstone
Distribuicion de algunos microorganismos segun su pH(Adaptado de Madigan et
al., Brock Biology of Microorganisms, 2003)
How does the geology influence the microbiology (or is it the other way around?)
El geiser ‘Cinder Pool’
Ambientes radioactivos
QuickTime™ and aTIFF decompressor
are needed to see this picture.
INTEC-666 pool
Dual corrosion cells
Biofilm on AL-6061
Acridine orange-stained AL
Al fondo de los oceanos
JAPEX sampling in the Nankai Trough, Japan
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