BIOL2421: Module1.Ch01 - The Microbial World

Describe two ways in which Pasteur removed microorganisms from the substances he worked with.

"Pasterization" 1. Used swan-necked Pasteur flask to prevent reintroduction of microorganisms (particulate matter) 2. Extensive heating to sterilize

What are four properties exhibited by all living organisms? (hint: book discusses three, the fourth is added in pink)

1. Metabolism - Genetic (Replication, Transcription, Translation) and Catalytic (Catabolism, Anabolism) 2. Growth 3. Evolution 4. Responsiveness - the ability to react to the surrounding environment and alter cellular behavior.

Describe the experimental procedure that would satisfy all four of Koch's postulates.

1. Observe blood/tissue under the microscope. 2. Streak agar plate with sample from either a diseased or a healthy animal. 3. Inoculate healthy animal with cells of suspected pathogen. 4. Remove blood/tissue sample and observe by microscopy (use of pure culture)

Define Koch's postulates:

1. The suspected pathogen must be present in all cases of 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

What are three structures found in all forms of cellular life? (hint: don't include cytoplasm, even though all cells have it, it's not technically a structure)

1. cytoplasmic (cell) membrane 2. ribosomes 3. chromosomes/DNA

Why are rRNAs excellent candidates for observing phylogenetic relationships?

1. universally distributed 2. functionally constant 3. highly conserved (that is, slowly changing) 4. of adequate length to provide a deep view of evolutionary relationships ribosomal RNA (rRNA) molecules and the genes that encode them could be used to infer evolutionary relationships between organisms. Ribosomal RNAs are components of ribosomes, the structures that synthesize new proteins in the process of translation

Critical Thinking: Pasteur was lucky with his experiment. Why do you think that is? In other words, what could have gone wrong that would have made it look as if spontaneous generation were true?

?

You identify a new living organism that needs to be classified into one of the three domains of life. The organism has a cell wall, a cell membrane, and a nucleoid region. Based on this information, which of the three domains could you choose? A) Bacteria or Archaea B) Bacteria, Archaea, or Eukarya C) Bacteria only D) Eukarya only E) Archaea only

A) Bacteria or Archaea

Who showed that viruses were filterable agents that were smaller than bacteria? A) Beijerinck B) Koch C) Pasteur D) Winogradsky

A) Beijerinck

Consider the following two statements: I) Ecosystems are influenced by microbial activities. II) Microbial ecosystems remain constant over time. A) Only statement I is correct. B) Only statement II is correct. C) Both statements I and II are correct. D) Neither statement I nor II is correct.

A) Only statement I is correct.

Which of the following characteristics was found in the earliest cellular organisms? A) anaerobic metabolism B) multicellularity C) membrane-bound nucleus D) photosynthesis

A) anaerobic metabolism

What kinds of cells do NOT have a cell wall? A) animal cells B) algal cells C) fungal cells D) bacterial cells

A) animal cells

Control of infectious diseases currently is the result of all of the following EXCEPT __________. A) eradication of hundreds of pathogens B) increased understanding of disease processes C) improved sanitary and public health practices D) the use of antimicrobial agents

A) eradication of hundreds of pathogens

Two types of light microscopy that do not use stains but are able to increase the contrast of samples being viewed are __________. A) phase contrast and dark-field microscopy B) atomic force and confocal laser scanning microscopy C) fluorescence and dark-field microscopy D) phase contrast and differential interference contrast microscopy

A) phase contrast and dark-field microscopy

Louis Pasteur developed vaccines for all of the following diseases EXCEPT __________. A) smallpox B) anthrax C) fowl cholera D) rabies

A) smallpox

An example of a differential stain is __________. A) the Gram stain B) flagella stain C) staining nucleic acids D) spore stain

A) the Gram stain

Who was the first person to visualize bacteria under a microscope?

Antoni van Leeuwenhoek (1632-1723)

Who was the scientist that discovered endospores? A) Koch B) Cohn C) Hooke D) Pasteur

B) Cohn

Which types of organisms are the most important for the maintenance of life on Earth? A) plants B) microorganisms C) animals D) humans

B) microorganisms

What type of glassware was used to settle the controversy surrounding spontaneous generation? A) Erlenmeyer flask B) swan-necked flask C) side-armed flask D) volumetric flask

B) swan-necked flask

What is chemolithotrophy? A) the incorporation of cellular carbon from CO2 B) the oxidation of inorganic compounds linked to energy conservation within a cell C) the utilization of light energy as a mechanism of energy conservation within a cell D) the oxidation of organic compounds linked to energy conservation within a cell

B) the oxidation of inorganic compounds linked to energy conservation within a cell

Which domains of life are prokaryotic? Provide examples.

Bacteria and Archaea ex) E. coli, streptococcus bacterium, amoeba, paramecium

In what size range is the diameter of a typical prokaryotic cell? A) 0.5 to 2 nm B) 0.5 to 2 cm C) 0.5 to 2 μm D) 0.5 to 2 mm

C) 0.5 to 2 μm

Koch's postulates __________. A) can identify all cases of all infectious diseases in all organisms B) can be applied to mixed (not pure) cultures of microorganisms C) are used to link cause and effect in an infectious disease D) can be used to identify pathogens that can not be grown in a laboratory

C) are used to link cause and effect in an infectious disease

In microscopy, what is the limiting factor in our ability to see microorganisms clearly? A) transmission B) ability to stain C) resolution D) magnification

C) resolution

A colony on a Petri plate arises from a single cell. How many cells does a typical bacterial colony contain? A) 10^1 B) 10^3 C) 10^5 D) 10^7

D) 10^7

Which of the following cellular properties is NOT found in all cells? A) growth B) evolution C) metabolism D) differentiation

D) differentiation

What is the method that uses selective culture media and incubation conditions to isolate specific microorganisms from natural samples? A) streaking B) anaerobic culture C) dilution culture D) enrichment culture

D) enrichment culture

Staining of microbial samples before microscopy is used to __________. A) increase lens aperture B) increase size C) increase magnification D) increase sample contrast for better visibility

D) increase sample contrast for better visibility

Briefly describe the history of life on earth and discuss the impact microorganisms had on the evolution of life.

Earth is about 4.6 billion years old. First microbial cells appeared between 3.8 and 4.3 billion years ago. Earth's atmosphere was anoxic (O2 was absent), and only nitrogen (N2), carbon dioxide (CO2), and a few other gases were present until ~2.6 billion years ago. Only microorganisms capable of anaerobic metabolisms (that is, metabolisms that do not require O2) could survive under these conditions.

Which domains of life are eukaryotic? Provide examples.

Eukarya ex) plants, animals, algae, protozoa, fungi

What is the difference between eukaryotic and prokaryotic genomes?

Eukaryotic DNA: Linear chromosomes within a nucleus Much larger DNA (up to billions of base pairs) Prokaryotic DNA: Generally a single circular chromosome that aggregates to for the nucleoid region May also contain plasmids (extrachromosomal DNA) Small, compact (0.5-10 million base pairs)

What did he discover about fermentation?

Fermentation is a biologically (not just chemically) mediated process

What is a gene? How does it relate to an organism's genome?

Gene: The basic biological unit of heredity. A DNA segment that contributes to phenotype/function. Genes are passed from parents to offspring and contain the information needed to specify traits. Genome is the entire set of genetic instructions found in a cell. An organism's genome consists of all of its genetic material, including all genes and all of the DNA that's in the spaces between the genes.

What is the difference between prokaryotes and eukaryotes?

Prokaryote vs eukaryote: key differences Prokaryotes: Nucleus: Absent Membrane-bound organelles: Absent Cell structure: Unicellular Cell size: Smaller (0.1-5 μm) Complexity: Simpler DNA Form: Circular Examples: Bacteria and Archaea Eukaryotes: Nucleus: Present Membrane-bound organelles: Present Cell structure: Mostly multicellular; some unicellular Cell size: Larger (10-100 μm) Complexity: More complex DNA Form Linear Examples: Plants, animals, algae, protozoa (protists) fungi

Who was the first person to visualize a microorganism under a microscope?

Robert Hooke (1635-1703) Fruiting structures of molds Book Micrographia (1665)

Describe the experimental set up Pasteur used to disprove spontaneous generation.

The unique swan-neck feature of the flasks used in Pasteur's experiment allowed air to enter the flask but prevented the entry of bacterial and fungal spores. Pasteur's experiment consisted of two parts. In the first part, the broth in the flask was boiled to sterilize it. When this broth was cooled, it remained free of contamination. In the second part of the experiment, the flask was boiled and then the neck was broken off. The broth in this flask became contaminated.

Organelle

a bilayer-membrane-enclosed structure such as the mitochondrion, found in eukaryotic cells

Evolution

a change over time in gene sequence and frequency within a population of organisms, resulting in descent with modification

Culture

a collection of microbial cells grown using a nutrient medium

Pure culture

a culture containing a single kind of microorganism

Briefly describe the characteristics of Bacteria

a domain of life consisting of microorganisms that have prokaryotic cell structure and are distinct from Archaea Prokaryotes Single-celled microorganisms with no nuclei Cell wall made of peptidoglycan Sensitivity to antibiotics First amino acid during protein synthesis: Formylmethionine No histones No organelles Ribosomes 70S

Briefly describe the characteristics of Archaea:

a domain of life consisting of microorganisms that have prokaryotic cell structure and are distinct from Bacteria Ptokaryotes single-celled microorganisms with no nuclei Cell wall does not contain peptidoglycan No sensitivity to antibiotics First amino acid during protein synthesis: Methionine Histones No organelles Ribosomes 70S

Briefly describe the characteristics of Eukarya:

a domain of life consisting of organisms that have eukaryotic cell structure; includes algae, protists, fungi, slime molds, plants, and animals Eukaryotes All organisms whose cells have nuclei to enclose their DNA apart from the rest of the cell Cell wall in plants and fungi, composed of polysaccharides No sensitivity to antibiotics First amino acid during protein synthesis: Methionine Histones Organelles Ribosomes 80S

Colony

a macroscopically visible population of cells growing on solid medium, arising from a single cell

Nucleus

a membrane-enclosed structure in eukaryotic cells that contains the cell's DNA genome

Enrichment culture technique

a method for isolating specific microorganisms from nature using specific culture media and incubation conditions

Macromolecules

a polymer of monomeric units, for example, proteins, nucleic acids, polysaccharides, and lipids

Enzyme

a protein (or in some cases an RNA) catalyst that functions to speed up chemical reactions

Cell wall

a rigid layer present outside the cytoplasmic membrane; it confers structural strength on the cell

Cytoplasmic membrane

a semipermeable barrier that separates the cell interior (cytoplasm) from the environment

Ribosomes

a structure composed of RNAs and proteins upon which new proteins are made

[QuizShow] ________ first described bacterial cells in a 1684 manuscript by referring to them as "wee animalcules." a. Antoni van Leeuwenhoek b. Carl Woese c. Louis Pasteur d. Robert Hooke

a. Antoni van Leeuwenhoek

[QuizShow] Griffith's transformation in Streptococcus pneumoniae led to the discovery of a. DNA as the molecular basis of heredity. b. mRNA as the template for protein synthesis. c. polysaccharides as the major component of capsules. d. Archaea as the third domain of life.

a. DNA as the molecular basis of heredity.

[QuizShow] True or False: In the early 1900s, a United States resident was most likely to die from infectious disease, whereas today nonmicrobial systemic diseases are the leading cause of death. a. TRUE b. FALSE

a. TRUE

[QuizShow] True or False: Pasteur discovered that Aspergillus exclusively acts on only one of the two isomeric forms of tartrate, showing that organisms can discriminate between optical isomers. a. TRUE b. FALSE

a. TRUE

[QuizShow] True or False: Prior to research performed by Pasteur, the production of alcohol was thought to be a purely chemical process and not catalyzed by microorganisms. a. TRUE b. FALSE

a. TRUE

[QuizShow] What does the first of Koch's postulates state? a. The disease-causing organism must always be present in animals suffering from the disease but not in healthy animals. b. The isolated organism must cause the disease when inoculated into healthy, susceptible animals. c. The organism must be cultivated in a pure culture away from the animal body. d. The organism must be isolated from the newly infected animals and cultured again in the laboratory, after which it should be seen to be the same as the original organism.

a. The disease-causing organism must always be present in animals suffering from the disease but not in healthy animals.

[QuizShow] Which group is NOT a domain in the tree of life? a. Viruses b. Bacteria c. Archaea d. Eukarya

a. Viruses

Metabolism

all biochemical reactions in a cell

Plasmid

an extrachromosomal genetic element that is not essential for growth

Microorganism

an organism that is too small to be seen by the unaided human eye

Genome

an organism's full complement of genes

For which diseases did Koch discover the causative agent?

anthrax, fowl cholera, and rabies

[QuizShow] Which individual compared rRNA sequences to generate the tree of life, establishing the three-domain system? a. Frederick Griffith b. Carl Woese c. Robert Hooke d. Robert Koch

b. Carl Woese

[QuizShow] Which taxonomic group of microorganisms is primarily responsible for the oxygenation of Earth? a. anaerobic bacteria b. cyanobacteria c. filamentous algae d. purple phototrophic bacteria

b. cyanobacteria

[QuizShow] Which of the following is NOT a property/process of all living cells? a. transcription b. differentiation c. evolution d. metabolism

b. differentiation

[QuizShow] The majority of phyla from domain Bacteria were discovered by a. sequencing isolates cultivated in laboratory media. b. sequencing DNA extracted directly from environmental samples. c. using enrichment media. d. transmission electron microscopy.

b. sequencing DNA extracted directly from environmental samples.

Are microorganisms unicellular, multicellular, or both?

both

[QuizShow] Which of the following is NOT a reason rRNA genes are able to be used to infer evolutionary relationships by phylogenetic analysis? a. It is present in all cells. b. It has the same function in all cells. c. It is highly variable in sequence, quickly changing. d. It is of sufficient length to be significant.

c. It is highly variable in sequence, quickly changing.

[QuizShow] In fulfilling ________, guinea pigs were used as a model animal to conclusively show that Mycobacterium tuberculosis was the bacterial pathogen that caused tuberculosis. a. disease theory b. spontaneous generation c. Koch's postulates d. pathogen differentiation

c. Koch's postulates

[QuizShow] Who developed the culturing technique to enrich for a certain population of microbial cells from a complex community based on a particular metabolic phenotype of interest? a. Frederick Griffith b. Joseph Lister c. Martinus Beijerinck d. Sergei Winogradsky

c. Martinus Beijerinck

[QuizShow] A rumen is the location where active microbial populations ________ ________, the main component of plant cell walls, into usable nutrient sources for the animal. a. ferment peptidoglycan b. respire peptidoglycan c. ferment cellulose d. respire cellulose

c. ferment cellulose

[QuizShow] Robert Koch was a trained ________ who initially developed a lot of his germ theory of disease by studying bacteremia of ________. a. chemist / Bacillus anthracis b. chemist / Mycobacterium tuberculosis c. physician / Bacillus anthracis d. physician / Mycobacterium tuberculosis

c. physician / Bacillus anthracis

[QuizShow] What was Pasteur's purpose in using a swan-necked flask rather than a traditional Erlenmeyer flask for his experiments on spontaneous generation? a. to prevent air from entering b. to be able to boil and sterilize the liquid medium c. to prevent large debris and microbes from entering d. all of the above

c. to prevent large debris and microbes from entering

[QuizShow] Which of the following circumstances is/are of concern in an attempt to fulfill Koch's postulates? a. Infected animals do not show the same symptoms as infected humans. b. The suspected pathogen is present in healthy humans. c. An axenic (or "pure") culture cannot be obtained. d. All of the above are of concern.

d. All of the above are of concern.

[QuizShow] Which of the following is true regarding the diversity of life? a. Domain Archaea does not contain any disease-causing organisms. b. Bacteria can vary greatly in size and range up to 700 μm in length. c. Microbial Eukarya may have first arisen two billion years ago, well before fungi, plants, or animals. d. All of the above are true.

d. All of the above are true.

[QuizShow] _______ published the first known sketches of molds in the book Micrographia in 1665, making it the first documented description of microorganisms. a. Antoni van Leeuwenhoek b. Robert Koch c. Louis Pasteur d. Robert Hooke

d. Robert Hooke

[QuizShow] Who was the first to reveal how certain bacteria can obtain energy from inorganic compounds (such as nitrogen- and sulfur-containing compounds) rather than organic substrates? a. Antoni van Leeuwenhoek b. Frederick Griffith c. Martinus Beijerinck d. Sergei Winogradsky

d. Sergei Winogradsky

[QuizShow] Koch used ________ to culture bacterial cells in his laboratory. a. agar b. gelatin c. potatoes d. agar, gelatin, and potatoes

d. agar, gelatin, and potatoes

[QuizShow] Which of the following is NOT an example of how microorganisms are beneficial? a. fermentation of dairy products b. production of ethyl alcohol for biofuel c. cycling of nutrients like nitrogen and phosphorus d. biofilm formation in fuel tanks, pipes, and drains

d. biofilm formation in fuel tanks, pipes, and drains

[QuizShow] An expert in ________ would be the best person to consult about cleaning soil contaminated with carcinogenic compounds, while the production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________. a. industrial microbiology / phylogeny b. phylogeny / bioremediation c. biotechnology / industrial microbiology d. bioremediation / biotechnology

d. bioremediation / biotechnology

[QuizShow] Which pathogen did Pasteur help treat by developing a vaccine against it? a. Escherichia coli b. influenza virus c. Mycobacterium tuberculosis d. rabies virus

d. rabies virus

[QuizShow] What principal accomplishment of Pasteur's work was essential to refute the spontaneous generation theory? a. bacterial isolation techniques b. developing nutrient agar plates for culturing microorganisms c. development of the light microscope d. sterilization

d. sterilization

Sterile

free of all living organisms (cells) and viruses

Eukaryotic

having a membrane-enclosed nucleus and various other membrane-enclosed organelles; cells of Eukarya

Growth

in microbiology, an increase in cell number with time

Medium

in microbiology, the liquid or solid a nutrient mixture(s) used to grow microorganisms

Intercellular communication

interactions between cells using chemical signals

Prokaryotic

lacking a membrane-enclosed nucleus and other organelles; cells of Bacteria or Archaea

Differentiation

modification of cellular components to form a new structure, such as a spore

What did Pasteur argue was the actual cause of putrefaction?

particulate matter (dust including microorganisms)

What type of cells have cell walls?

prokaryotic cells and eukaryotic plant cells

Resolution

the ability to distinguish two objects as distinct and separate when viewed under the microscope

Contrast

the ability to resolve a cell or structure from its surroundings

Nucleoid

the aggregated mass of DNA that makes up the chromosome(s) of prokaryotic cells

Cytoplasm

the fluid portion of a cell, enclosed by the cytoplasmic membrane

Describe the concept of spontaneous generation

the hypothesis that living organisms can originate from nonliving matter

Aseptic technique

the manipulation of sterile instruments or culture media in such a way as to maintain sterility

Motility

the movement of cells by some form of self-propulsion

Magnification

the optical enlargement of an image

DNA replication

the process by which information from DNA is copied into a new strands of DNA

Transcription

the synthesis of an RNA molecule complementary to one of the two strands of double-stranded DNA molecule

Translation

the synthesis of protein by a ribosome using the genetic information in a messenger RNA as a template

Horizontal gene transfer

the transfer of genes between cells through a process uncoupled from reproduction

Ribosomal RNA (rRNA)

the types of RNA found in ribosome