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Where are Microbes found and what are microbes?
- organisms that are invisible to the naked eye
The first person to report seeing microbes under the microscope was an Englishman
Anton van Leeuwenhoek
- Father of microbiology
- Although not the FIRST TO DISCOVER THE MICROSCOPE or to use magnifying lens, he
- was the first to see and describe bacteria.
- Disproved Spontaneous Generation
- By proving maggots are not spontaneously produced in rotten meat
- Important founder of medical microbiology
- Breakthroughs in the causes and preventions of diseases
- Microbes are everywhere - even in the air and dust
- The Germ Theory of Disease
- Microbes (germs) cause disease and specific microbes cause specific diseases
How are microbes impt? Impact on Human Health
- •Disadvantage: Cause disease (flu, STD, infection) and basis for bioterrorism (anthrax)
- •Benefit: Digestion, synthesis of vitamins, and production of antibiotics
How are microbes impt? Balance of Nature
- •Maintain balance of environment (microbial ecology)
- •Basis of food chain
- •Nitrogen fixation
How are microbes impt? Environmental
- •Bioremediation: use microbes to remove toxins (oil spills)
- •Recycling sewage
How are microbes impt? Industrial
- •Genetic engineering
- •Synthesis of chemical products
- •Manufacture of food and drink
How are microbes impt? Agricultural
- •Use of microbes to control crop pests•Increase livestock•Food spoilage
What are stains
A stain, or dye, is a molecule that can bind to a structure and give it colo
Most microbial stains are cationic
cationic (positively charged), or basic dyes, such as methylene blue, crystal violet, or safrannin
Some microbial stains are Anionic dyes
anionic dyes (negatively charged), or acidic dyes, such as nigrosin or India ink
Stains → combine chemically with the
the bacterial protoplasm.
- colored cation + colorless anion
- e.g. methylene
- blue (methylene blue chloride)
MB+ + Cl-
An ion or group of ions having a positive charge
a negatively charged ion
- colored anion + colorless cation e.g. eosin ( Na+ plus
is a fluorescent red dye resulting from the action of bromine on fluorescein. It can be used to stain cytoplasm
Acidic dyes do not stain the
- do not stain the bacterial cell → they can stain the background material with a contrasting
use one dye and reveal basic cell morphology.
use two or more dyes and distinguish various properties or organisms
color the background around cells and their parts, which resist taking up the stain. (acidic dyes will “stick” to the glass slide since glass has a + charge).
include all bacteria, FREE DNA no nucleus
include all organisms other than bacteria, HAVE NUCLEUS
prokaryotes and eukaryotes What is the difference?
- •Prokaryotes are much smaller and simpler constructed than eukaryotes
- –Membrane bound organelles
- –Linearvs circular DNA–Size
Prokaryotes and Eukaryotes are similiar in
- Cell membrane
- Have nucleic acid (DNA)
- Hace cytoplasm
- or Filamentous (strings of single cells)•Collective prokaryote biomass outweighs all eukaryotes combined by at least tenfold. •They exist almost everywhere, including places where eukaryotes cannot
Prokaryote cells are simply built
- •capsule: slimy outer coating
- •cellwall: tougher middle layer
- •cell membrane: delicate inner skinFlagella
Almost all prokaryotes have cell walls external to the plasma membrane composed of
What is metabolism?
refers to all of the chemical processes that occur inside living cells
What is ATP?
- •ATP is a molecule with stored energy
- •Biological reactions require energy to proceed.
ATP consists of
adenosine (adenine + ribose) and a triphosphate group
Difference between aerobic and anaerobic metabolism.
- •Aerobic respiration (in the presence of oxygen) - A large amount of ATP is made during aerobic respiration. •Anaerobic respiration (in the absence of oxygen). - NAD+ is recycled during the anaerobic process of fermentation
In aerobic respiration, ATP forms as
- •ATP forms as electrons are harvested, transferred along the electron transport chain and eventually donated to O2 gas.
- –Oxygen is required!
- –Glucose is completely broken-down
Glycolysis – coupled reactions used to make
- •used to make ATP.
- –Occurs in cytoplasm
- –Doesn’t require O2
- •harvests electrons and uses their energy to power ATP production.–Only in mitochondria–More powerful
- •Anaerobic respiration occurs in the absence of oxygen.•Different electron acceptors are used instead of oxygen (sulfur, or nitrate).•Does not ATP
The term microbial growth refers to
to the growth of a population (or an increase in the number of cells), not to an increase in the size of the individual cell.
Cell division leads to
•the growth of cells in the population
Factors Regulating Growth
- •Environmental conditions: temperature, pH, osmotic pressure
- •Generation time
How do bacteria acquire new DNA?
Environmental Factors Influencing Growth
- •Temperature•O2 •pH•Osmotic Pressure (tonicity)•Moisture•Hydrostatic pressure•Radiation•Nutrients
How do bacteria acquire new DNA?
- bacteria acquire new DNA by
DNA transformation involves the transfer of naked DNA into a recipient cell
The transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells
Is the process by which DNA is transferred from one bacterium to another by a virus