Microbiology

• organisms that are invisible to the naked eye
• Virus
• Fungi
• Protozoa 
• Bacteria
• Archaea
• Algae
• Helminths

The first person to report seeing microbes under the microscope was an Englishman

• 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

smallpox inoculation

• •Disadvantage: Cause disease (flu, STD, infection) and basis for bioterrorism (anthrax)
• •Benefit: Digestion, synthesis of vitamins, and production of antibiotics

• •Maintain balance of environment (microbial ecology)
• •Basis of food chain
• •Nitrogen fixation
• •Photosynthesis

• •Bioremediation: use microbes to remove toxins (oil spills)
• •Recycling sewage

• •Genetic engineering
• •Synthesis of chemical products
• •Manufacture of food and drink

• •Use of microbes to control crop pests
• •Increase livestock
• •Food spoilage

A stain, or dye, is a molecule that can bind to a structure and give it colo

cationic (positively charged), or basic dyes, such as methylene blue, crystal violet, or safrannin

anionic dyes (negatively charged), or acidic dyes, such as nigrosin or India ink

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
• eosin-).

is a fluorescent red dye resulting from the action of bromine on fluorescein. It can be used to stain cytoplasm

• do not stain the bacterial cell → they can stain the background material with a contrasting
• color

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 are much smaller and simpler constructed than eukaryotes
• –Membrane bound organelles
• –Nucleus
• –Reproduction
• –Linearvs circular DNA
• –Size

• Cell membrane
• Have nucleic acid (DNA)
• Hace cytoplasm

• •Single-celled(unicellular)
• 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

• •capsule: slimy outer coating
• •cellwall: tougher middle layer
• •cell membrane: delicate inner skin
• Flagella

Peptidoglycan

refers to all of the chemical processes that occur inside living cells

• •ATP is a molecule with stored energy
• •Biological reactions require energy to proceed.

adenosine (adenine + ribose) and a triphosphate group

• •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

• •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

• •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

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.

•the growth of cells in the population

• •Nutrients
• •Environmental conditions: temperature, pH, osmotic pressure
• •Generation time

• •Temperature
• •O2 
• •pH
• •Osmotic Pressure (tonicity)
• •Moisture
• •Hydrostatic pressure
• •Radiation
• •Nutrients

•  bacteria acquire new DNA by
• transformation
• conjugation
• transduction

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