Bio150 Chapter 01 - An Invisible World Flashcards
“Microorganisms or microbes”
Very small organisms; many types are too small to see without a microscope, although some parasites and fungi are visible to the naked eye.
Ötzi the Iceman
5300yr old mummy preserved in ice in Alps. Infected with eggs of the parasite Trichuris trichiura. Also found evidence of Borrelia burgdorferi, a bacterium that causes Lyme disease
Trichuris trichiura
Parasite that lays eggs causing abdominal pain and anemia. Ötzi had this.
Borrelia burgdorferi
Bacterium that causes Lyme disease. Ötzi had this.
Fomitopsis betulinus
Fungus that has laxative and antibiotics. Ötzi was carrying this and was thought to be using it to treat his infections.
Cloaca Maxima
A giant sewer system in ancient Rome to help remove waste. Was thought to aide in reducing waterborne epidemics.
Hippocrates
Greek physician (460-370BC) “Father of Western Medicine.” Rejected idea of illnesses caused by supernatural forces. Posited that they were naturally caused.
Thucydides
Greek philosopher (460–395 BC) “Father of Scientific Theory.” Advocated for evidence-based analysis of cause-and-effect. Observed that survivors of the Athenian plague, which killed 1/3 of the population, were unaffected by those who were actively sick. This shows an early understanding of immunology.
Marcus Terentius Varro
Roman writer (116–27 BC) who proposed things we cannot see can cause diseases. “Stay away from neighborhood swamps, they’ll make you sick.”
Antonie van Leeuwenhoek
Dutch (1632–1723) was first to develop lens strong enough to see microbes. Observed ‘animalcules’ which we now know were protists.
Golden Age of Microbiology
Spawned a host of new discoveries between 1857 and 1914
Louis Pasteur
French chemist (1822–1895) , showed that individual microbial strains had unique properties and demonstrated that fermentation is caused by microorganisms. He also invented pasteurization, a process used to kill microorganisms responsible for spoilage, and developed vaccines for the treatment of diseases, including rabies, in animals and humans
Robert Koch
German physician (1843–1910), was the first to demonstrate the connection between a single, isolated microbe and a known human disease. Discovered the bacteria that cause anthrax, cholera, and tuberculosis
Bacillus anthracis
Bacteria that causes anthrax
Vibrio cholera
Bacteria that causes cholera
Mycobacterium tuberculosis
Bacteria that causes tuberculosis
Taxonomy
classification, description, identification, and naming of living organisms
Carolus Linnaeus
Swedish (1701–1778). In 1735 published Systema Naturae, an 11-page booklet in which he proposed the Linnaean taxonomy, a system of categorizing and naming organisms using a standard format so scientists could discuss organisms using consistent terminology
Linnean taxonomy
This divided the natural world into three kingdoms: animal, plant, and mineral (the mineral kingdom was later abandoned). Within the animal and plant kingdoms, he grouped organisms using a hierarchy of increasingly specific levels and sublevels based on their similarities. The names of the levels in Linnaeus’s original taxonomy were kingdom, class, order, family, genus (plural: genera), and species.
Phylogenies
taxonomies that took into account the evolutionary relationships
Today, phylogenic analyses include what comparisons?
genetic, biochemical, and embryological comparisons
Linnaeus’s tree of life contained just two main branches for all living things:
Animal and Plant Kingdoms
Ernst Haeckel
German who proposed another kingdom, Protista, for unicellular organisms. Later proposed a fourth kingdom, Monera, for unicellular organisms whose cells lack nuclei, like bacteria.
Robert Whittaker
American, (1920–1980) who proposed adding another kingdom, Fungi, in his tree of life. Whittaker’s tree also contained a level of categorization above the kingdom level, the empire or superkingdom level to distinguish between organisms that have membrane-bound nuclei in their cells (eukaryotes) and those that do not (prokaryotes)
Empire Prokaryota contained:
Only Kingdom Monera.
Empire Eukaryota contained:
The other four kingdoms: Fungi, Protista, Plantae, and Animalia.
Viruses are not found in any of these trees because?
They are not made up of cells and thus it is difficult to determine where they would fit into a tree of life.
Modern taxonomy relies heavily on?
Comparing the DNA, RNA, or proteins from different organisms. The more similar the nucleic acids and proteins are between two organisms, the more closely related they are considered to be.
Carl Woese discovered what?
What appeared to be a “living record” of the evolution of organisms. He and his collaborator George Fox created a genetics-based tree of life based on similarities and differences they observed in the gene sequences coding for small subunit ribosomal RNA (rRNA) of different organisms. In the process, they discovered that a certain type of bacteria, called archaebacteria (now known simply as archaea), were significantly different from other bacteria and eukaryotes in terms of their small subunit rRNA gene sequences.
Archaebacteria is also known as?
Archaea
To accommodate this difference in gene sequences coding for rRNA, what was created?
A tree with three Domains above the level of Kingdom: Archaea, Bacteria, and Eukarya
Analysis of small subunit rRNA gene sequences suggests archaea, bacteria, and eukaryotes all evolved from a common ancestral cell type. The tree is skewed to show a closer evolutionary relationship between?
Archaea and Eukarya than they have to Bacteria.
Horizontal gene transfer
When a gene of one species is absorbed into another organism’s genome. This is especially common in microorganisms and can make it difficult to determine how organisms are evolutionarily related. Consequently, some scientists now think in terms of “webs of life” rather than “trees of life.”
Binomial nomenclature
A two-word naming system for identifying organisms by genus and specific epithet
Bergey’s Manual
Standard references for identifying and classifying different prokaryotes. Without easily observable macroscopic features like feathers, feet, or fur, scientists must capture, grow, and devise ways to study their biochemical properties to differentiate and classify microbes. Because so many bacteria look identical, methods based on nonvisual characteristics must be used to identify them
Within one species of microorganism, there can be several subtypes called
Strains. While different strains may be nearly identical genetically, they can have very different attributes. Think “E. coli”
An object must measure about how many micrometers (μm) to be visible without a microscope
100 micrometers (μm)
Typical animal cell measures roughly how many μm across
10 micrometers (μm )
Bacterial cells are typically about how many μm
1 micrometer (μm)
Viruses can be 10 times smaller than bacteria
10 times smaller than bacteria, 0.1micrometers (μm), or 100nanometers (nm)
Acellular
Not composed of cells
Microorganisms are found in each of the three domains of life:
Archaea, Bacteria, and Eukarya
Microbes within the domains Bacteria and Archaea are all?
Prokaryotes (their cells lack a nucleus)
Microbes in the domain Eukarya are?
Eukaryotes (their cells have a nucleus
Bacteria are prokaryotic because?
Their genetic material (DNA) is not housed within a true nucleus.
Most bacteria have cell walls that
Contain peptidoglycan.
Bacteria are often described in terms
Of their general shape.
Common bacterial shapes include
spherical (coccus), rod- shaped (bacillus), or curved (spirillum, spirochete, or vibrio)
“coccus”
Spherical
“bacillus”
Rod-shape
“spirillum, spirochete, or vibrio”
Curved
Some bacteria are photosynthetic, such as
Oxygenic cyanobacteria, anoxygenic green sulfur, and green nonsulfur bacteria.
Bacteria have a wide range of _____ capabilities and can grow in a variety of ______, using different combinations of ______
Metabolic capabilities, variety, nutrients
Archaea are
Unicellular prokaryotic organisms. Different evolutionary histories than bacteria, as well as significant differences in genetics, metabolic pathways, and the composition of their cell walls and membranes. Their cell walls do not contain peptidoglycan, but are often composed of a similar substance called pseudopeptidoglycan
Some archaea live in the ______ , but none have been shown to be ______.
Human body, human pathogens
The domain Eukarya contains
All eukaryotes, including uni- or multicellular eukaryotes such as protists, fungi, plants, and animals.
The major defining characteristic of eukaryotes is
Their cells contain a nucleus.
Protists are
An informal grouping of eukaryotes that are not plants, animals, or fungi. Algae and protozoa are examples of protists.
What is singular for Algae?
Alga
What is plural for Algs?
Algae
Algae are
Protists that can be either unicellular or multicellular and vary widely in size, appearance, and habitat. Their cells are surrounded by cell walls made of cellulose, a type of carbohydrate. They are photosynthetic organisms that extract energy from the sun and release oxygen and carbohydrates into their environment
Algae cells walls are made of?
surrounded by cell walls made of cellulose
What is cellulose?
A type of carbohydrate found in algae cell walls
Is Algae photosynthetic?
Algae are photosynthetic organisms that extract energy from the sun and release oxygen and carbohydrates into their environment
What is Agar?
A gel derived from algae, can be mixed with various nutrients and used to grow microorganisms in a Petri dish.
Protozoa
Protists that make up the backbone of many food webs by providing nutrients for other organisms. Very diverse. Some photosynthetic, some free-living, some parasitic. Most harmless but some pathogens to animals and humans. Move in three ways.
How do protozoas move?
Help from hair-like structures called cilia or whip-like structures called flagella. Others extend part of their cell membrane and cytoplasm to propel themselves forward. These cytoplasmic extensions are called pseudopods (“false feet”).
Cilia
Hair-like structures which help protozoas move?
Flagella
Whip-like structures which help protozoas move?
Pseudopods
Cytoplasmic extensions or “false feet” that help protozoas propel forward by extending part of their cell membrane and cytoplasm.
Fungi
Eukaryotes. Some are multicellular such as mushrooms, which resemble plants, but they are actually quite different. Not photosynthetic, and their cell walls are usually made out of chitin rather than cellulose.
Yeast
Eukaryotes. Unicellular fungi. More than 1000 known species. Found in many different environments, from the deep sea to the human navel. Good and bad forms (Beer, wine, yeast infections, thrush)
What are fungi cell walls made of?
Chitin rather than cellulose
Molds
Eukaryotes. Multicellular fungi. Long filaments that form visible colonies. Critical to decompositions. Can cause allergies or produce disease-causing metabolites called mycotoxins.
Mycotoxins
Disease causing metabolites produced by mold.
Helminth
Multicellular parasitic worms. Not technically microorganisms, as most are large enough to see without a microscope. However, these worms fall within the field of microbiology because diseases caused by them involve microscopic eggs and larvae.
Dracunculus medinensis
A helminth, also known as a “guinea worm.” Causes dizziness, vomiting, diarrhea, and painful ulcers on the legs and feet when the worm works its way out of the skin. Can be removed by rolling it around a matchstick.
What organism causes guinae worm disease?
Dracunculus medinensis. Mostly eradictated thanks to water sanitation in 80’s. About 126 cases in 2014.
Viruses
Acellular microorganisms, which means they are not composed of cells. Consists of proteins and genetic material, either DNA or RNA, but never both. that are inert outside of a host organism. However, by incorporating themselves into a host cell, are able to co-opt the host’s cellular mechanisms to multiply and infect other hosts. Can infect all types of cells.
Size: 10 times smaller than bacteria, 0.1micrometers (μm), or 100nanometers (nm)
Creutzfeldt-Jakob disease (CJD) and what causes it?
A type of transmissible spongiform encephalopathy (TSE). Caused by prions which are extremely small, about one-tenth the size of a typical virus. They contain no genetic material and are composed solely of a type of abnormal protein. It is 85% spontaneous with 90% of patients dead within a year. Diagnosed with brain autopsy.
Who was Otzi?
“The Iceman.” A 5,300yr old mummy found frozen in alps. Infected with eggs of the paraside Trichuris trichiura and Borrelia burgdorferi (Lyme disease). May have been treating self with Fomitopsis betulinus fungus.
Who was Hippocrates?
“Father of Western medicine.” Greek physician. Dismissed idea that disease was caused by supernatural forces.
Who was Thucydides?
“Father of scientific history” because he advocated for evidence based analysis. Observed concept of immunity during Athenian plague which killed 1/3 of the population.
Who was Varro?
One of first people to propose the concept that things we cannot see can cause disease.
Who was Leeuwenhoek?
“Father of microbiology.” First to develop a lens powerful enough to view microbes. Was able to observe bacteria and protists.
Who was Pasteur?
Showed that individual microbial strains had unique properties. Demonstrated that fermentation caused by microorganisms. Invented pasteurization. Developed vaccines.
Who was Koch?
First to demonstrate the connection between a single, isolated microbe, and a known human disease. Discovered anthrax (Bacillus anthracis), cholera (Vibrio cholera), and tuberculosis (Mycobacterium tuberculosis).
Who was Linneaus?
Early taxonomist who published the 14-page “Systema Naturae” which proposed a format for categorizing and naming organisms so scientists could all talk.
Who was Haeckel?
Proposed Kingdoms Protista and Monera.
Who was Whittaker?
Proposed 5th Kingdom of Fungi.
Who was Bergey?
A group of scientists who made the Bergey’s Manuals to standardize the identification/classification of different prokaryotes.
Who was Woes?
Discovered what appeared to be a “living record” of the evolution of organisms. Created a genetics-based tree of life based on gene sequences coding for small subunit ribosomal RNA.
Who was Fox?
Collaborated with Woes to create genetics-based tree of life based on gene sequences coding for small subunit ribosomal RNA.
