Lecture One Flashcards
Microbiology is the study of?
organisms too small to be seen without magnification
Microorganisms include what?
All prokaryotes (= pre-nucleus),Some eukaryotes (= true nucleus)
Microorganisms include…
Examples of prokaryotes (pre-nucleus)
Bacteria
Archaea
Microorganisms include…
Examples of Some eukaryotes (= true nucleus)
Protozoa Most Algae Some Fungi Helminths (parasitic worms) -Adult forms are macroscopic, but infective forms are microscopic Viruses
Microbiology/microorganisms DO NOT include…
Insects
macroscopic fungi (mushrooms) and algae (e.g. kelp)
Individual cells of macroscopic organisms
Microbiology also includes the study of
viruses
Viruses
non-cellular, non-living biological entities
All known organisms can be infected by
≥1 type of virus
Viruses are…
Protein-coated genetic elements (DNA or RNA)
Parasitic; dependent on their infected host
Connected with the evolution of microbes and humans
Smaller than cellular microbes (~20-200 nm)
Some aspects of microbes
make them easy to study…
-Many can reproduce rapidly
(often ~20 min to 2 hrs/generation)
-Can be quickly grown in large populations in the laboratory
-Great ways to observe and study evolution!
Others aspects make them difficult objects of study!
- Can’t be seen directly
- Microscopes and other indirect means are used to study them
- Most microbes have yet to be grown in the lab…
Prokaryotes include Bacteria and Archaea and have been on the planet for about
3.5 billion years
Eukaryotic organisms arose about
- 8 billion years ago
- eventually formed multicellular animals
Most of the history of life on Earth is
microbial!
Oxygenic photosynthesis:
: Light-fueled conversion of carbon dioxide to organic material that does produce oxygen.
Cyanobacteria
Evolved in bacteria ~2.5 billion years ago
Photosynthesis
is the major source of oxygen on Earth
Oxygenic photosynthesis:
Lead to the use of oxygen for aerobic respiration
Photosynthetic microbes account for
> 50% of the Earth’s photosynthesis
Microbes are major forces that
that drive the structure and content of the soil, water, and atmosphere: Biogeochemical cycles
Produce gases such as CO2, N2O, and CH4 that regulate the
temperature of the earth
The enormous community of microbes in soil and sediments influence
weathering, mineral extraction, and soil formation
Bacteria and fungi live in close associations with plants that
help them obtain nutrients and protect them against disease
Production and preservation of various foods:
like
E.g. Cheese, bread, alcohol, yogurt, sauerkraut, kimchee
Production of chemicals and antibiotics
Bioremediation:
Naturally occurring or artificially introduced microbes to restore stability or clean up toxic pollutants
Many applications of microorganisms and their products in
in genetic engineering and biotechnology
Human microbiome:
set of microbes that are present on a typical human
human Microbes outnumber
our own cells by >10-fold!
Recent studies indicate the human microbiome
may be involved in human health in very complex ways
Most microorganisms that associate with humans
cause no harm
Pathogens:
microbes that cause disease
The World Health Organization (WHO) estimates that there are
are 10 billion new infections caused every year by microbes
Infectious diseases are among the most common cause of
death in the U.S. and worldwide: death toll is ~13 million people/year worldwide
In the 1660s Robert Hooke studied?? why is her famous?
studied household objects, plants, and trees using a simple magnifying glass
In the late 1600’s Antonie van Leeuwenhoek, a Dutch linen merchant, manufactured
simple microscopes to see threads in fabrics
Also observed “wee animalcules” scraped from his and others’ teeth
Constructed over 250 small microscopes that could magnify up to 300x
Antonie van Leeuwenhoek was the first to?
First person to observe bacteria by looking at standing rainwater samples
Microbes disease, 4/10 top causes of death are microbioal which 10?
respiratory infections, HIV/AIDS, Diarrheal diseases, tuberculosis
What is spontaneous generation?
The belief that invisible vital forces present in matter led to the creation of life
abiogenesis
the now discredited theory that living organisms can arise spontaneously from inanimate matter; spontaneous generation
biogenesis
saying that living things only arise from others of their same kind, proven because of the discovery of microbes
Louis Pasteur was played an important role in microbioloy because?
- Studied the roles of microbes in fermentation of alcoholic beverages
- He disapproved abiogensis
Pasteur’s Swan Neck Flask Experiment
Ask ??’s Slide 37
Ferdinand Cohn:
discovery of endospores and sterilization
Oliver Wendell Holmes and Ignaz Semmelweis
the importance of aseptic techniques and hand washing by physicians attending patients
Joseph Lister:
Used aseptic techniques in surgery
Robert Koch:
developed a series of postulates that verified Pasteur’s germ theory of disease and established a link between a microbe and the disease it caused (Chap. 11)
What laid the foundation for the field of microbiology??
pure culture, the recognition that microorganisms exist and the ability to grow them in
Who is responsible for the Discovery of antibiotics
1928, Alexander Flemming:
Allowed for better control of microbial infections
More recent rise of antibiotic resistance has spurred searches for new antibiotics from environmental microbes
Discovery of restriction enzymes (1970’s) made what impact??
Proteins that cleave DNA at specific sequences
Most are isolated from bacteria
Greatly advanced molecular biology, biotechnology
Invention of polymerase chain reaction (1980’s) discovery allowed/enhanced??
- Allowed for amplification of specific regions of DNA
- Enhanced by an enzyme from thermophilic microbes
Advances in DNA sequencing (2000’s - today) made what improvements?
DNA sequencing has become much cheaper over the last 15 years
This has allowed a much greater understanding of the evolution and potential functions of microbes, as well as other organisms
A Scientific name is a combination of?
the genus (generic) and species (specific) names
What does Nomenclature mean?
The assignment of scientific names to various taxonomic categories and to individual organisms
Categories (highest to lowest) for Classification?
Domain
Kingdom (not used for prokaryotes)
Phylum
Class
Order
Family
Genus
Species
Strain (for Bacteria and Archaea) or subspecies
Taxonomy essentially combines the two:
a formal system for organizing, classifying, naming, and identifying living things
The Universal Web of Life started of as two kingdoms started by?
Darwin and Haeckel, plants and animals
standard 5 kingdom system by Robert Whittaker includes what groups?
Animals Plants Fungi Protists Monera
This classical 5 kingdom system
was based mostly on what?
morphological or
chemical characteristics
What is Monera??
(Bacteria and Archaea) are relatively morphologically simple and were therefore thought not to be very diverse -No distinction was made between Bacteria and Archaea SLIDE 44
The Woese-Fox System:
Named after Carl Woese and George Fox
What was the The Woese-Fox System based off of? (2 Key points)
Based on analysis of gene (DNA) sequences, not e.g. morphology
- Conserved small subunit ribosomal RNA sequences (SSU rRNA)
- Evolution (sequence changes) in this and other conserved
The Woese-Fox System allowed the analysis of
Analysis of these sequences revealed that some “monera”, formed a group distinct from Bacteria: the Archaea
The Woese-Fox System: an entirely new system was proposed based on domains brought what three groups in the Woese-Fox 3 Domain tree of life
Bacteria
Archaea
Eukarya
The Woese-Fox System of Taxonomy (what does it say about bacteria and archaea and eukaryotes?
Bacteria and Archaea are both prokaryotes, but they are as different from each other as either of them are from us (humans) or other Eukaryotes!
The textbook mostly ignores Archaea…why?
• Why are helminths (complex, multicellular animals) covered under microbiology?
Helminths (parasitic worms)
• Adult forms are macroscopic, but infective forms
are microscopic
Electron microscopy is generally required to visualize what type of microbe? Which types can generally be visualized by light microscopy?
Images taken using electron microscopy
(with false coloring), size nm, viruses
Light: red blood cells
Which types of microbes were first to appear?
Cyanobacteria
Approximately when did Cyanobacteria first appear, and what impact did their evolution have on Earth’s atmosphere?
~2.5 billion years ago,
Lead to the use of oxygen for aerobic respiration
Oxygenic photosynthesis: Light-fueled conversion of carbon
dioxide to organic material that does produce oxygen.
Photosynthetic microbes account for
>50% of the Earth’s photosynthesis
• What are some examples of ways in which humans make use of microbes and their products or activities?
-Microbes are major forces that drive the structure and content of
the soil, water, and atmosphere: Biogeochemical cycles
-Bioremediation: Naturally occurring or
artificially introduced microbes to restore
stability or clean up toxic pollutants
-Production and preservation of various foods:
- E.g. Cheese, bread, alcohol, yogurt, sauerkraut, kimchee
• Production of chemicals and antibiotics
• What is the human microbiome? How does the number of total microbial cells present in the human microbiome compare to the total number of human cells in the body?
set of microbes that are present on a typical human Microbes outnumber our own cells by >10- fold! -ten trillion cells in the whole body
• Do most microbes associated with humans (or plants) cause disease? Be able to interpret Table 1.1 in the textbook regarding the comparison of the number of deaths caused by microbes (infectious diseases) vs. other causes.
most cause NO harm
4/10 causes of death are microbial (repiratory infections, HIV/AIDS, Diarrheal diesease, Tuberculosis
• What is the germ theory of disease? How did the ability to grow microorganisms in pure culture contribute to the germ theory of disease?
germ theory of disease and established a link between a microbe and the disease
it caused
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