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What are the two themes of microbiology

Understanding basic life processes and Applying knowledge to benefit humans


What are microbes good for

Model systems for understanding cellular processes in all organisms


What are the importance of microorganisms

They are the oldest form of life, largest mass of living material on Earth, carry out major processes for biogenochemical cycles, can live practically anywhere, organisms require microbes to survive


What are microorganisms

They are microscopic single cells, some simple multicellular organisms and viruses (but not cellular)


What are two fundamental cell types for microorganisms

Prokaryotes and Eukaryotes


What are prokaryotes

They do not contain a nucleus or membrane-bound organelles


What are eukaryotes

They are usually bigger, more complex, and contain a nucleus and membrane-bound organelles. Most are microorganisms


What are the 3 domains of life

Bacteria, Archaea, and Eukaryotes


What are viruses

Called bacteriophages, they are not cells and have no metabolism of their own, they are obligate parasites of both prokaryotic and eukaryotic cells in all 3 domains of life


In the bacterial cell, what is the Cell Membrane

The barrier that separates the inside of the cell, cytoplasm, from the outside environment


In the bacterial cell, what is the Cell Wall

It is present in most mirobes and confers structural strength and prevents osmotic lysis


In the bacterial cell, what is the nucleoid

It is the region in the bacteria that contains the chromosome (DNA)


In the bacterial cell, what is the flagella

Structure used for motility


What are the 7 characteristics of living systems

1. Metabolism
2. Reproduction
3. Differentiation
4. Communication
5. Movement
6. Evolution
7. Regulation


What is metabolism

Chemical transformation of nutrients and allows grwoth


What is reproduction

Generation of two cells from one


What is differentiation

Synthesis of new substances or structures that modify the cell (only in some microbes, ex. spores)


What is communication

Generation of, and response to, chemical signals (not in all microbes)


What is movement

Via self-propulsion, several forms (only in some microbes)


What is evolution

Genetic changes in cells that are transferred to offspring


What is regulation

The ability to turn processes on and off. Regulate the activities of enzymes, gene expression, metabolism, movement.


What are the 2 fundamental functions of cells

Cells as catalysts and as coding devices


What do cells do as catalysts

They carry out chemical reactions with enzymes


What are enzymes

Proteins (or RNA) catalysts that accelerate chemical reactions and can be regulated


What do cells do as coding devices

Cells store and process information that is passed on to offspring (genetics) during reproduction through DNA, evolution


What is transcription

DNA copied to RNA


What is translation

RNA codes for amino acids in protein. Proteins are critical for all aspects of cell structure and metabolism


What is a population

A group of the same species of organisms


What is a community

A group of different species (different populations interacting)


What is a habitat

The environment in which a microbial population lives


What is an ecosystem

Refers to all the living organisms plus abiotic physical and chemical constituents of their envonrment


What controls the diversity and abundance of microbes

The resources (nutrients) and the environmental conditions (temp, pH, oxygen)


What can the microbial communities do to the environment

The activities of microbial communities can affect the chemical and physical properties of their habitats (ex. removal of nutrients and the excretion of waste products (oxygen in the atmosphere))


Which bacteria caused the earth to rust over 2 billion years ago and form an oxygen atmosphere



What is LUCA

Last Universal Common Ancestor: ancestral cell from which all extant cells/organisms descended


What are the basic components of life

dsDNA genomes, ribosomes, tRNA, genetic code, etc


How old is the Earth

4.6 billion years old


When did the first cells appear

Between 3.8-3.9 billion years ago


The Earth was anoxic until how long ago?

The atmosphere was anoxic (no oxygen) until 2 billion years ago. Before that, metabolisms were exclusively anaerobic until evolution of oxygen-producting phototrophs


How long was life exclusively microbial

Until about 1 billion year ago


Where are microbes found

Microbes are found in almost every environment and most microbial cells are found in oceanic and terrestrial SUBSURFACE'S, so not easily seen. You have 10x more microbe cells in and on you than human cells


What is the impact of microorgansisms on humans

They are both beneficial and harmful to humans


How has control of iinfectious diseases changed during the last century

The control of infectious diseases during the last century has greatly improved, the top 10 killers list no longer has a majority of microbial diseases


What are some positive impacts of microorganisms on agriculture

Nitrogen-fixing bacteria, cellulose degrading microbes in the rumen (cows), and regeneration of nutrients in soil and water


What are some negative impacts of microorganisms on agriculture

Diseases in plants and animals


What do nitrogen fixing bacteria do

Converts N2 gas into NH3 ammonia


What does rumen do

Grass -> Cellulose -> Glucose -> Microbial Fermentation -> Fatty Acids or CO2 and CH4 waste products


What are some positive impacts of microorganisms on food?

Microbial transformations (fermentations) yield: dairy products (cheese, yogurt, buttermilk), and other food products (sauerkraut, pickles, leavened breads, beer, and wine)


What are some negative impacts of microorganisms on food?

Food spoilage by microorganisms. Requires special preservation of foods (drying, salting, canning, refrigeration, and freezing)


What is industrial microbiology

Production of organic compounds, antibiotics, fermentation products (acids and alcohols)


How are microbes used for biofuels

Sugars, methane, ethanol, and hydrogen are used in biofuel production


How are microbes for cleaning up pollutants

Bioremediation - some bacteria can eat or degrade compounds that are toxic to humans or that damage the environment


How are the genetic resources of microorgansisms used

The exploitation of natural microbes for production of antibiotics, enzymes, and various chemicals such as ethanol. Genetic engineering of microbes to generate products of value to humans such as insulin and many other drugs and biochemicals


Who was Robert Hooke

The first to describe microbes


Who was Antoni van Leeuwenhoek

The first to describe bacteria


Who was Ferdinand Cohn

Founded the field of bacterial classification and discovered bacterial endospores


Who was Louis Pasteur

Discovered that living organisms discriminate between organic optical isomers, a property of biological enzymes, that alcoholic fermentation was a biologically mediated process, disproved the theory of spontaneous generation, and developed vaccines for anthrax, fowl cholera, and rabies


What is spontaneous generation

The hypothesis that living organisms can originate from nonliving matter


What experiment did Pasteur perform to disprove spontaneous generation

He poured a nonsterile liquid broth into a flash, bent the neck of the flask so nothing would be able to enter, and sterilized the broth by heating it. Over time the liquid remained completely sterile and dust and microorganisms got stuck in the bend in the neck. In the control experiment, he tipped the flask to the side which allowed microorganisms to enter through the bend at the neck, and after a short period of time the liquid was no longer pure.


Who was Robert Koch

Demonstrated the link between microbes and infectious diseases, developed Koch's postulates, and developed techniques for solid media and obtaining pure cultures of microbes


What is a pure culture

A colony containing one one type of bacteria


What are Koch's postulates

1. The suspected pathogen must be present in all cases of the disease and absent from healthy animals
2. The suspected pathogen must be grown in pure culture
3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal
4. The suspected pathogen must be reisolated and shown to be the same as the original


Whoa is Martinus Beijernick

Developed the enrichment culture technique


What is the enrichment culture technique

Most environments contain too many different microbes to easily study. They can be isolated from natural samples in a highly selective fashion by manipulating nutrient and incubation conditions.
Ex. Nitrogen-fixing bacteria are isolated on medium lacking nitrogen compounds


Who is Sergei Winogradsky

The concept of chemolithotrophy, demonstrated that specific bacteria are linked to specific biogeochemical transformations


What is chemolithotrophy

Use of minerals as a source of "food" energy


What are the two directions of microbiology nowadays

Applied and Basic


What is microbial systematics

The science of grouping and classifying microorganisms, understanding diversity


What is microbial physiology

Study of nutrients, metabolism, growth, and products


What is cell biology/cytology

Study of cellular structure


What is microbial biochemistry

Study of microbial enzymes and chemical reactions


What is bacterial genetics

Study of heredity, variation, and evolution. Provided the foundation of Molecular Biology, gene expression


What is virulology

Study of viruses


What is molecular biology

Study of basic mechanisms of microbe life processes. Biotechnology


What is biotechnology

Manipulation of genes and cellular genomes. DNA from one organism can be inserted into a bacterium and the proteins encoded by that DNA harvested for use.