Microbiology Chapter 1 Flashcards
What are Microorganisms?
Organisms too small to be seen with the naked eye.
What are Microbes?
Acellular members of the microbial world.
Microorganisms have existed on earth for approximately how long?
3.5 billion years
What has evolved from ancestral bacteria?
Plants, animals, and modern microorganisms.
What year was the science of microbiology founded?
1674
Who is credited with the discovery of microbes? How did he describe his discovery?
Robert Hooke. Described ‘microscopical mushroom’ (common bread mold) in 1665.
Who was first to observe a single celled microbe? What other observation did he make?
Antoni van Leeuwenhoek (1632-1723). Made observation that heat killed microbes.
What is Spontaneous Generation?
Belief that life arises spontaneously from non-living material.
Who first disproved Spontaneous Generation? What was his experiment?
Francesco Redi. Demonstrated worms on rotting meat came from eggs of flies landing on meat (1668).
Many who still believed in spontaneous generation believed heating destroyed “________” necessary for spontaneous generation.
Vital Force
In 1749, ___________ demonstrated boiled broths still produced microorganisms.
John Needham
Who contradicted Needham’s results? What did he change?
Father Spallanzani. Boiled broths longer, sealed flasks by melting necks. Broths remained sterile unless neck cracked.
Who demonstrated that air is filled with microorganisms? How did he do it?
French chemist Louis Pasteur. Filtered air through cotton plug, many trapped microorganisms looked identical to those found in broths.
What is biogenesis?
Describes the production of living things from other living things.
What experiment ended the concept of spontaneous generation forever?
Pasteur’s “swan-neck flasks.” Boiled broths remained sterile despite opening to air, microorganisms from air settled in the bends of flasks.
The _________ describes the process of science.
Scientific Method
When testing a hypothesis, you include a _______ to help rule out alternative explanations.
Control
What is a Scientific Theory?
An explanation supported by a large amount of evidence.
What is the normal microbiota?
Population of microorganisms that is carried by the human body.
How does the normal microbiota play an essential role in human health?
Prevent disease by competing with disease-causing microbes. Aid in digestion. Promote development of immune system (May decrease allergies, asthma). May affect brain chemistry and body weight.
Normal microbiota is ______ to the number of cells in our body.
Equal
What is the Human Microbiome Project? When was it started?
DNA sequencing studies to characterize microbial communities that inhabit the human body. 2007.
What are the two definitions of Microbiome?
Total genetic content of the microbial community.
The microbial community itself.
Less than ______ of microbes can be cultured; others are characterized by DNA sequencing.
1%
Why do some consider the human body a superorganism?
Our own cells interact with our normal microbiota to form a single cooperative unit.
How many of the total cells in our body are bacteria?
0.03%
What is the National Microbiome Institute (NMI)?
Started in 2016. Expands scope of microbiome research.
What are functions of microorganisms in the environment?
Recycling of nutrients. Oxygen production through photosynthesis. Nitrogen fixation. Decomposers of material (Cellulose).
How are microorganisms involved in food production?
Baking bread using yeast. Fermentation of grains to produce beer. Fermentation of milk into cheese, butter, and yogurt.
How are microorganisms involved in biodegradation?
Degrade environmental pollutants. Lessen damage from oil spills.
What is Bioremediation?
Use of microorganisms to hasten the decay of pollutants.
What are some commercially valuable products that are synthesized by bacteria?
Antibiotics, Ethanol, Hydrogen gas and certain oils, Amino acids, Insect toxins, Cellulose, and Hydrobutyric acid (Disposable diapers and plastic).
What is Biotechnology?
Use of microbiological and biochemical techniques to solve practical problems.
What some genetic engineering applications of bacteria?
Production of medications by certain microorganisms, such as insulin for treatment of diabetes. Production of plants with desirable qualities.
Why are microbes used as research tools?
Model organisms have same fundamental metabolic and genetic properties as higher life forms.
Bacteria can’t grow without what? How do we measure this?
Water. Water Activity, ranging from 0 to 1.
What components have reduced incidence of infection diseases?
Modern sanitation, vaccination, and antibiotic treatment.
What are three diseases that have been almost eliminated by these new preventative measures?
Smallpox, Plague Deaths, and Polio
What are three infectious diseases in non-human populations?
Irish Potato Famine in 1800s, English Foot-and-Mouth disease in 2001, “Wheat Blast” in 2016
What is an Emerging Infectious Disease?
A disease that has become more common in the last 35 years.
What are some causes of Emerging Infectious Diseases?
Disease agents evolve, become resistant to antibiotics. Mobile populations carry pathogens around the globe.
_______ may be caused by pathogens, including ________ and ________.
Chronic diseases; Stomach ulcers and cervical cancer.
Who discovered Penicillin?
Scottish physician Alexander Fleming (1881-1955).
What are the two basic cell structures?
Prokaryotic and Eukaryotic
All living things can be classified into one of three domains:
Bacteria (Prokaryotes), Archea (Prokaryotes), and Eukarya (Eukaryotes).
What are the two methods for scientifically naming microbes?
Name often reflects characteristic of organism or honors scientist who worked with it.
Are bacteria single celled or multi-cellular?
Single-celled
What are two ways that archaea and bacteria are different chemically? What about the environment differences?
Cell walls lack peptidoglycan, ribosomal RNA sequences different. While some are found in moderate environments, archaea are extremophiles (found in high temperature, high salt concentrations, etc.)
T/F: Some bacteria are photosynthetic.
True
What are the four types of eukaryotes that are studied by microbiologists?
Fungi, Algae, Protozoa, and Helminths (Worms)
Out of the four groups of eukaryotes, 3 use organic material for energy and 1 uses sunlight. Which one uses sunlight?
Algae
What is the common macroscopic reproductive structure characteristic of some fungi?
Mushroom
How do fungi take in nutrients?
Secrete enzymes onto organic materials, and then take in the released nutrients.
How do fungi spread?
Filamentous molds spread by release of microscopic spores (conidia).
Are fungi single celled or multicellular?
Diverse group ranging from single-celled to multicellular molds.
Are algae single celled or multicellular?
Both.
What gives algae its characteristic green color?
Chloroplasts that contain chlorophyll.
In what environment are algae typically found?
Usually live near surface of water or in moist habitat.
What are two characteristics of algae that are distinct from prokaryotes?
Rigid cell walls and flagella.
Are protozoa single celled or multicellular?
Single celled
Are protozoa larger than prokaryotes?
Yes, protozoa are larger.
How do protozoa obtain energy?
Ingesting organic compounds.
Do protozoa have a cell wall?
No
T/F: Most protozoa are motile.
True
What are three examples of helminths?
Roundworms, tapeworms, and flukes.
If helminths can be seen with the naked eye, why are they still considered microorganisms?
Adults can be seen with the naked eye, but their eggs and larvae are still microscopic.
What are the three groups of acellular infections agents?
Viruses, viroids, and prions.
Are viruses, prions, and viroids considered living or non-living? Why?
Non-living. They are not composed of cells (acellular).
Once a host cell is infected by a virus, what are the two outcomes?
May kill the host cell. May remain within the host cell and replicate viral genetic information as host cell multiplies.
How do viruses multiply?
Multiply using host cell machinery and nutrients. Inactive outside of host.
Describe the structural makeup of viruses.
Nucleic acid packaged in protein coat. Contain either DNA or RNA.
T/F: Viruses can only infect some forms of life.
False, all forms of life can be infected by different types.
Unique to viroids, viroids can cause a disease in what species?
Can cause plant disease
What two groups are both obligate intracellular agents?
Viruses and viroids
What do viroids structurally consist of?
Consist of only a single short piece of RNA.
What is the main difference between the genetic makeup of viruses vs. viroids?
Viruses consist of both DNA or RNA, while viroids consist of only RNA.
There is no evidence that viroids cause disease in what group?
Humans
Structurally speaking, what are prions?
Infectious proteins (Misfolded versions of normal cellular proteins found in the brain.)
How are prions “contagious”?
Misfolded version in contact with normal version causes it to also misfold.
An abundance of abnormal proteins form what structure? This causes what in the brain?
Fibrils. Cells die leaving spaces in brain (mad cow disease).
Out of viruses, viroids, and prions: which is most difficult to get rid of and why?
Prions. Due to their protein structure, they are resistant to usual sterilization procedures.
