IM Flashcards
a systematized body of knowledge based on factual evidence comes from the Latin word scientia meaning “to know”
Science
study of microorganisms
Microbiology
are organisms too small to be seen by the unaided eye.
Microorganisms (mo’s)
Microbiology revolves around 2 interconnected themes:
(1) understanding the living world of microscopic organisms; and
(2) applying our understanding of microbial life processes for the benefit of humankind and planet Earth
is defined as the study of how microbial cell’s structures, growth and metabolism function in living organisms. It includes the study of bacteria, fungi, viruses and parasites.
Microbial physiology
is a subject area within microbiology and genetic engineering. Also, studies microorganisms for different purposes using the organisms’ whole genome or some specific genes.
Microbial genetics
comprises of biochemical reactions in microbial growth, various modes and mechanisms of pathogenesis required in causing infection/ diseases within the host. It focuses on the study of microbial growth, microbial cell structure, microbial metabolism, advanced functions as well as interactions of biological macromolecules like proteins, fatty acids and nucleic acids which are the fundamental aspect and basis of functions sustaining life.
Microbial biochemistry
Studies natural
phenomena
Natural Science
Social life and relations
between human beings
Social Science
study of inorganic
phenomena
Physical Science
study of organic or living
phenomena
Biological Science
Basic Science
Cytology
Histology
Anatomy
Morphology
Physiology
Taxonomic Science
Botany
Bacteriology
Mycology
Virology
Zoology
Applied Biology
Medicine
Nursing
Dentistry
Veterinary Med
Horticulture
‒Microbiology uses and develops tools
for probing the fundamental
processes of life
‒ Model organisms/systems
As a basic biological science
‒microbiology is at the center of many
important aspects of human and
veterinary medicine, agriculture, and
industry.
✓soil fertility and domestic animal welfare
✓production of antibiotics and human
proteins
As an applied biological science
•Smallest forms of life but constitute bulk of
biomass of earth.
Microorganisms
• Carry out many necessary chemical reactions
for higher organisms
Microorganisms
•Evolution of oxygen
Microorganisms
• Proposed the theory of
spontaneous generation
• Also called abiogenesis
• Idea that living things can arise
from nonliving matter
• Idea lasted almost 2000 years
Aristotle (384 –322 BC)
• For centuries, people based their beliefs on their
interpretations of what they saw going on in the world
around them without testing their ideas
• They didn’t use the scientific method to arrive at
answers to their questions
• Their conclusions were based on untested
observations
Spontaneous Generation
Observation: Every year in the spring, the Nile River flooded
areas of Egypt along the river, leaving behind nutrient-rich mud
that enabled the people to grow that year ’ s crop of food.
However, along with the muddy soil, large numbers of frogs
appeared that weren’t around in drier times.
• Conclusion: It was perfectly
obvious to people back then
that muddy soil gave rise to
the frogs
Observation: In many parts of Europe, medieval farmers stored
grain in barns with thatched roofs (like Shakespeare’s house).
As a roof aged, it was not uncommon for it to start leaking. This
could lead to spoiled or moldy grain, and of course, there were
lots of mice around.
Conclusion: It was
obvious to them that the
mice came from the
moldy grain.
Observation: In the cities centuries ago, there were no
sewers, no garbage trucks, no electricity, and no refrigeration.
Sewage flowed down the streets, and chamber pots and left
over food were thrown out into the streets each morning. Many
cities also had major rat problems and a disease called
Bubonic plague.
Conclusion: Obviously, all the
sewage and garbage turned
into the rats.
Observation: Since there were no refrigerators, the
mandatory, daily trip to the butcher shop, especially in
summer, meant battling the flies around the carcasses.
Typically, carcasses were “ hung by their heels, ” and
customers selected which chunk the butcher would carve off
for them.
Conclusion: Obviously, the
rotting meat that had been
hanging in the sun all day was
the source of the flies
• Recipe for bees:
➢Kill a young bull, and bury it in an upright position
so that its horns protrude from the ground. After a
month, a swarm of bees will fly out of the corpse.
Abiogenesis Recipes
• Recipe for mice:
➢Place a dirty shirt or some rags in an open pot or
barrel containing a few grains of wheat or some
wheat bran, and in 21 days, mice will appear. There
will be adult males and females present, and they will
be capable of mating and reproducing more mice.
Abiogenesis Recipes
• In 1668, _________, an Italian
physician, did an experiment with
flies and wide-mouth jars containing
meat
Francesco Redi (1668)
• Redi used open & closed jars which contained meat.
• His hypothesis was that rotten meat does not turn into
flies.
• He observed these jars to see in which one(s) maggots would
develop.
Redi’s Experiment
• Evidence against spontaneous generation:
1. Unsealed – maggots on meat
2. Sealed – no maggots on meat
3. Gauze – few maggots on gauze, none on meat
Redi’s (1626-1697) Experiments
Disproving Spontaneous
Generation
Louis Pasteur
Disproving Spontaneous
Generation of Microbes
Anton van Leeuwenhoek (1674)
- began making and looking through simple
microscopes
• He examined water and visualized tiny animals, fungi, algae,
and single celled protozoa; “animalcules”
• By end of 19th century, these organisms were called
microbes
Anton van Leeuwenhoek (1674)
• Showed that microorganisms flourished in various
soups that had been exposed to the air
• Claimed that there was a “life force” present in the
molecules of all inorganic matter, including air and
the oxygen in it, that could cause spontaneous
generation to occur
John Needham (1745)
Chicken Broth
Needham’s Experiment
• Needham’s experiments seemed to support the idea
of spontaneous generation
• People didn’t realize bacteria were already present
in Needham’s soups
• Needham didn’t boil long enough to kill the
microbes
Needham’s Results
• Boiled soups for almost an hour and
sealed containers by melting the slender
necks closed.
• The soups remained clear.
• Later, he broke the seals & the soups
became cloudy with microbes.
Lazzaro Spallanzani’s (1765)
Conclusion of Spallanzani’s Results
• Critics said sealed vials did not allow enough air for organisms
to survive and that prolonged heating destroyed “life force”
• Therefore, spontaneous generation remained the theory of
the time
the debate had become so heated that the
Paris Academy of Sciences offered a prize for any
experiments that would help resolve this conflict
• The prize was claimed in 1864 by Louis Pasteur, as he
published the results of an experiment he did to disprove
spontaneous generation in microscopic organisms
By 1860
Pasteur’s Problem
•Hypothesis: Microbes come from cells of organisms on dust
particles in the air; not the air itself.
• Pasteur put broth into several special S-shaped flasks
(swan-necked flask)
• Each flask was boiled and placed at various locations
• Pasteur’s S-shaped/swan-necked flask kept microbes
out but let air in.
• Proved microbes only come from other microbes (life
from life) - biogenesis
The Theory of Biogenesis
Francisco Redi filled jars with decaying meat.
1668
Lazzaro Spallanzani boiled nutrient solutions in
flasks.
1765
Louis Pasteur demonstrated that microorganisms
are present in the air.
1861
Beginnings
• The Universe (maybe)
• Primitive Earth—Not paradise as we know it—much different
than Earth today
How could these simple molecules be made into
more complex ones?
Abundant energy sources, lots of time.
— a Russian
biochemist
➢published ‘The Origin of Life’ in Nov. 1923
➢‘ life arose gradually from inorganic
molecules, with “building blocks” like
amino acids forming first and then
combining to make complex polymers’
Alexander Oparin (1938)
➢showed organic compounds could be
synthesized under primitive conditions
• Miller’s atmosphere was not correct
• Fumarolic gases (volcanic activity)
‒ CO2, N2, SO2, H2S
• UV light was intense
• Heat (volcanic activity)
• Organic compounds synthesized as well
• Organic compounds brought by meteorites
• Mineral surfaces as catalyzers
Stanley Miller (1953)
➢represent some of the most pristine
matter known
➢chemical compositions match the
chemistry of the Sun more closely
than any other class of chondrites
Carbonaceous chondrites
➢”seeds everywhere”
➢states that the “seeds” of life exist
all over the Universe and can be
propagated through space from
one location to another
➢Life brought in on asteroids and
comets
Panspermia
Abiotic Chemical Evolution
• Synthesis and accumulation
• Polymerization
• Aggregation
• Origin of heredity
➢protobiont
➢precursors to the first true cells
➢a self-organized, endogenously
ordered, spherical collection of
lipids proposed as a stepping-stone
to the origin of life
Protocells
• believed to be the origin of
all life on earth
Evolution from the Last
Universal Common
Ancestor (LUCA)
-LUCA or progenotes-
Cell membranes of Eukarya and Bacteria are similar
• Fatty acids linked to glycerol by ester linkages in Eukarya and Bacteria
• Archaea do not produce long chain fatty acids (ether-linked isoprenoids)
• Chloroplast derived from a Cyanobacterium
• Mitochondrion from another Bacterium
Endosymbiotic evolution theory (Lynn Margulis)
Percent total of Marine Subsurface
66
Percent total of Terrestrial Subsurface
26
Percent total of Surface soil
4.8
Percent total of Oceans
2.2
Percent total of all other habitats
1.0
