Microbiology Chapter 1

First of some synthetic drugs

Quinine from tree bark was long used to treat malaria. Sulfonamides were synthesized.

Viroids

Simpler than viruses. Require host cell for replication. Consist of single short piece of RNA. No protective protein coat. Cause plant diseases. Some scientists speculate they. -may cause diseases in humans No evidence yet.

Prokaryote

Single-celled organism consisting of a prokaryotic cell; members of the domains Bacteria and Archaea are prokaryotes.

Describe Bacteria

Single-celled prokaryotes Prokaryote = "prenucleus" No membrane-bound nucleus No other membrane-bound organelles DNA in nucleoid Most have specific shapes (rod, spherical, spiral) Rigid cell wall contains peptidoglycan (unique to bacteria) Multiply via binary fission Many move using flagella

Why is a logarithmic scale necessary when comparing sizes of members of the microbial world?

Small size and broad size range of some members of the microbial world have required the use of measurements not commonly used in everyday life. Designating the sizes of prokaryotes and viruses.

Two types of cells?

Staphylococcus aureus and Escherichia coli. The first word (capitalized) is the genus, the second the specific epithet. After first use they may be abbreviated.

A microbiologist obtained two pure biological samples: one of a virus, and the other of a viroid. Unfortunately, the labels had been lost. The microbiologist felt she could distinguish the two by analyzing for the presence or absence of a single molecule. What molecule would she search for and why?

The presence of DNA. Because Viruses contain DNA and RNA, while Viroids only contain RNA.

Molecular Biology

The study of how DNA directs protein synthesis.

Why can viruses be so much smaller than cells and still replicate?

They live off and replicate on the source of their "host cell".

Biotechnology

Use of microbes to produce foods and chemicals, is centuries old.

Re-emerging diseases

Vaccination can become victim of own success. Lack of firsthand knowledge of dangers of diseases can lead people to fear vaccines more than the diseases. Diseases such as measles, mumps, whooping cough nearly eradicated from U.S. but could re-emerge with declining vaccination rates.

How does a viroid differ from a virus?

Viroid consists of RNA only, has no protein coat, simpler than viruses, infect plants. Viruses Consist of RNA or DNA, have a protein coat, infect all living things.

Why might the gauze masks not protect against the influenza virus?

Viruses are usually small enough to get through and transmitted through direct contact.

Name three non-living groups in the microbial world and describe their major properties.

Viruses described as obligate intracellular agents, consisting of either DNA or RNA, surrounded by a protein coat. Viroids are obligate intracellular agents and consisting of only RNA; no protein coat. Prions are abnormal form of a cellular protein, consisting of only protein; no DNA or RNA.

Give three reasons why life could not exist without the activities of microorganisms.

We would be depleted of oxygen in 20 years (microorganisms aid to replenish it). Degrading of cellulose. Conversion of nitrogen.

infectious diseases

When a pathogen overcomes the host's resistance, disease results.

Nucleoids are associated with 1. genetic information. 2. prokaryotes. 3. eukaryotes. 4. viruses. 5. prions. a) 1, 2 b) 2, 3 c) 3, 4 d) 4, 5 e) 1, 5

a) 1, 2

The Archaea 1. are microscopic. 2. are commonly found in extreme environments. 3. contain peptidoglycan. 4. contain mitochondria. 5. are most commonly found in the soil. a) 1, 2 b) 2, 3 c) 3, 4 d) 4, 5 e) 1, 5

a) 1, 2

Viruses 1. contain both protein and nucleic acid. 2. infect all domains of life. 3. can grow in the absence of living cells. 4. are generally the same size as prokaryotes. 5. always kill the cells they infect. a) 1, 2 b) 2, 3 c) 3, 4 d) 4, 5 e) 1, 5

a) 1, 2

The prokaryotic members of the microbial world include 1. algae. 2. fungi. 3. prions. 4. bacteria. 5. archaea. a) 1, 2 b) 2, 3 c) 3, 4 d) 4, 5 e) 1, 5

d) 4, 5

Antony van Leeuwenhoek could not have observed a) roundworms. b) Escherichia coli. c) yeasts. d) viruses.

d) viruses.

Benefits of normal microbiota

or normal flora. Prevent diseases by competing with pathogens. Development of immune system response. Aid in digestion.

What are microorganisms?

organisms that are too small to be seen with the unaided eye

Theory of Spontaneous generation:

"Life arises spontaneously from non-living material". Detractors (disprovers) included Francesco Redi, Louis Pasteur, John Tyndall.

Why are prions visible here when normal cellular proteins are not?

...

Why are viruses not microorganisms?

Because they are non-living. In order to be alive, an organism must be composed of one or more cells. Viruses are acellular (not consisting of, divided into, or containing cells) and are rather agents.

Why is the bacterium that causes anthrax such an effective agent of bioterrorism?

Because while they can lie dormant, they can suddenly become deadly with the right conditions. As a spore this makes them very resistant and able to survive and the spores could be carried easily through the air to be inhaled by those near it. Due to its toxicity it is a potent killer. Also invisible to the naked eye.

If Pasteur's swan-necked flasks had contained endospores, what results would have been observed?

Boiling would not have sterilized the broth in the first place, so the broth would not have stayed sterile for years when the flask was left upright.

The American Society for Microbiology is preparing a "Microbe-Free" banquet to emphasize the importance of microorganisms in the diet. What foods could not be on the menu?

Bread, milk, alcohol, cheese.

Bioremediation

Category of Biodegradation. Using microorganisms to hasten decay of pollutants. In example, Bacteria degrade organic matter in sewage. Bacteria degrade or detoxify pollutants such as oil and mercury.

Eukaryotic Cell

Cell type characterized by a membrane-bound nucleus.

Prokaryotic Cell

Cell type characterized by the lack of a membrane-bound nucleus.

Emerging diseases

Changing lifestyles increase opportunities to spread. Evolution of infectious agents previously unable to infect humans (e.g., HIV/AIDS, SARS). Pathogens can become resistant to antimicrobial medications (e.g., tuberculosis, malaria) Increased travel and immigration. Changes in population. Weakened immune systems (e.g., elderly, HIV/AIDS) Chronic diseases may be caused by bacteria.

Recombinant DNA

DNA made from two different sources. For example, Paul Berg inserted animal DNA into bacterial DNA, and the bacteria produced an animal protein.

Briefly describe some benefits of microbes in our lives.

Decompose organic waste. Produce industrial chemicals such as ethanol and acetone. Produce fermented foods such as vinegar, cheese, and bread. Produce products used in manufacturing (e.g., cellulase) and treatment (e.g., insulin). Are producers in the ecosystem by photosynthesis.

Erlich and "magic bullet"

Developed a synthetic arsenic drug, salvarsan, to treat syphilis. Could destroy a pathogen without harming the host.

Fleming and penicillin

Discovered the first antibiotic, observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus. Penicillin was tested clinically and mass produced.

Fungi

Diverse group. Molds and mushrooms. Single-celled (e.g., yeasts). Energy from degradation of organic materials. Chitin cell walls. Use organic chemicals for energy. Primarily live on land.

Protozoa

Diverse group. Single-celled. Complex, larger than prokaryotes. Most ingest organic compounds. No rigid cell wall. Most motile.

How do protozoa differ from both fungi and algae?

Do not have a rigid cell wall

Name some reasons for EID's

Emerging diseases, Re-emerging diseases

John Tyndall

English physicist. Proved Pasteur correct. Sterilizing broths required different times. Concluded that some microorganisms could exist in two forms: a cell that is readily killed by boiling, and one that is heat resistant. Realized hay infusions contained heat-resistant microbes.

In the designation Escherichia coli B, what is the genus? What is the species? What is the strain?

Escherichia is the genus. Coli is the species. B is the strain.

Describe the Domain Eucarya

Eukaryotes = "true nucleus" Membrane-bound nucleus and other organelles More complex than prokaryotes

Human parasitic worms

Eukaryotes. Multicellular animals. Parasitic flatworms and roundworms are called helminths. Microscopic stages in life cycles.

What type of cells make up molds and mushrooms?

Eukaryotic

fibrils

Fibril is a fine fiber, such as a myofibril or neurofibril. Neurofilaments are about 10 nanometers in diameter

Who was Robert Hooke?

First to observe a microorganism. Also credited with discovery (next to Antony Van Leeunwenhoek). Described 'microscopical mushroom' (common bread mold) in 1665. Coined term "cell". Published Micrographia, a book describing observations made with microscopes and telescopes. First person to visualize cells and fungi.

Who was Antony Van Leeunwenhoek?

First to observe bacteria. Drapery merchant. Made simple magnifying glass. Studied lake water. Observed 'animalcules'!

List five beneficial applications of bacteria.

Food production, bioremediation, antibiotics, amino acids used in dietary supplements, ethanol as a substitute for gasoline.

Ferdinand Cohn

German botanist. Discovered endospores.

Name one location where you could isolate members of the Archaea.

Hot springs. Great salt lake or dead sea.

Why might so many of the "new" diseases first appear or be identified in the United States and Western European countries?

I would say they are more developed. (documented) We have access to more.

Golden Age of Microbiology

Most pathogenic bacteria identified. Work on viruses began. Understanding that microscopic agents could cause disease led to control efforts. Huge improvements in past century in human health. Antibiotics to treat infectious diseases. Vaccines to prevent diseases.

Linnaeus and binomial nomenclature

Naming and classifying organisms. Each organism has two names: genus and specific epithet.

EID's or Emerging Infectious Diseases

New diseases and diseases increasing in incidence.

Viruses

Nucleic acid packaged in protein coat. Variety of shapes. Infect living cells, termed hosts. Multiply using host machinery, nutrients. Inactive outside of hosts: obligate intracellular parasites. All forms of life can be infected by different types.

Eukaryote

Organism composed of one or more eukaryotic cells; members of the domain Eucarya are eukaryotes.

Fermentation

Pasteur showed that microbes are responsible for fermentation. Is the conversion of sugar to alcohol to make beer and wine.

State three reasons why there is a resurgence of infectious diseases today.

People bringing old diseases from places where they still exist. Fear of vaccination or uneducated about how important it is. Increasing numbers of elderly who have weakened immune systems pick up disease.

Distinguishing features of: Algae

Plant or Protist Diverse group Single-celled or multicellular Photosynthetic Primarily live in water Rigid cell walls -Cellulose cell walls -Cell walls, flagella distinct from those of prokaryotes

Photosynthetic

Produce molecular oxygen and organic compounds. Contain chloroplasts withchlorophyll or other pigments.

Name the prokaryotic groups in the microbial world.

Bacteria and Archaea.

What are the three domains?

Bacteria, Archaea, Eucarya.

Steps to Kochs postulates

1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. 2. The microorganism must be isolated from a diseased organism and grown in pure culture. 3. The cultured microorganism should cause disease when introduced into a healthy organism. 4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

How might you distinguish a prokaryotic cell from a eukaryotic cell?

A prokaryotic cell does not contain a membrane-bound nucleus nor any other intracellular lipid-bound organelles, and there genetic information stored in DNA is found in the region nucleoid. A eukaryotic cell contain a membrane-bound nucleus and other organelles.

What general features of algae distinguish them from other eukaryotic microorganisms?

Algae have organelles called chloroplasts that contain chlorophylla.

Joseph Lister

Applying Pasteur's work showing that microbes are in the air, can spoil food, and cause animal diseases, used a chemical disinfectant to prevent surgical wound infections.

The members of which two domains cannot be distinguished microscopically?

Archaea and bacteria

Prions

Infectious proteins: misfolded versions of normal cellular proteins found in brain. Misfolded version forces normal version to misfold. -Abnormal proteins bind to form fibrils. -Cells unable to function. Cause several neurodegenerative diseases in humans, animals. Resistant to standard sterilization procedures.

Accomplishments of Francesco Redi

Italian biologist and physician. Demonstrated worms on rotting meat came from eggs of flies landing on meat. Took another 200 years to convincingly disprove spontaneous generation of microorganisms. One reason: conflicting results between laboratories.

What does Aseptic mean?

Knowledge of microorganisms led to this. Techniques to prevent contamination in medicine and in microbiology laboratories.

Describe Archaea

Like Bacteria, are prokaryotic. Similar shapes, sizes, etc. to Bacteria. Pleomorphic - meaning they can alter shape to conditions. Multiply via binary fission. unlike bacteria, lack peptidoglycan. Ribosomal RNA sequences different. Many are extremophiles. High salt concentration, temperature, pressure, pH.

Biogenesis:

Living things come from living things. Pasteur's S-shaped flask kept microbes out but let air in. Boiled infusions remained sterile despite opening to air. Ended arguments that unheated air or broths contained "vital force" necessary for spontaneous generation.

If you were asked to nominate one of the individuals mentioned in this chapter for the Nobel Prize, who would it be? Make a statement supporting your choice.

Louis Pasteur. He disproved spontaneous generation. Came up with some of the greatest test methods for proving the existence of microorganisms and there role in places. What he did led to the start of the "golden age of microbiology".

Normal Microbiota

Microbes normally present in and on the human body are

What organisms are in the domain Eucarya?

Microbial members include fungi, algae, protozoa. Algae and protozoa also termed protists Some multicellular parasites including helminths (roundworms, tapeworms) considered as well.

Contribution of Ignaz Semmelweis

advocated hand washing to prevent transmission of puerperal fever from one OB patient to another. Gave his life to prove this.

Pasteurization

application of a high heat for a short time.

Which disease was once thought to be due to stress but is now known to be caused by a bacterium? a) smallpox b) peptic ulcers c) AIDS d) plague e) influenza

b) peptic ulcers

Prokaryotes typically do not have a) cell walls. b) flagella. c) a nuclear membrane. d) specific shapes. e) genetic information.

c) a nuclear membrane.

The property of endospores that led to confusion in the experiments on spontaneous generation is their? a) small size. b) ability to pass through cork stoppers. c) heat resistance. d) presence in all infusions. e) presence on cotton plugs.

c) heat resistance.

The "Golden Age of Microbiology" was the time when a) microorganisms were first used to make bread. b) microorganisms were first used to make cheese. c) most pathogenic bacteria were identified. d) a vaccine against influenza was developed. e) antibiotics became available.

c) most pathogenic bacteria were identified.

obligate intracellular parasites

cannot reproduce outside their host cell.

Microorganisms play a role in a) disease. b) biodegradation. c) cheese production. d) nitrogen recycling. e) all of the above.

e) all of the above.

endospores

heat-resistant form of bacteria.

Nucleic acid

include DNA and RNA, are made from monomers known as nucleotides.

Jenner and Vaccination

inoculated a person with cowpox virus, who was then protected from smallpox. Vaccination is derived from vacca, for cow. The protection is called immunity.

Robert Koch and Koch's postulates

proved that a bacterium (Bacillus anthracis) causes anthrax and provided the experimental steps, "Koch's postulates", to prove that a specific microbe causes a specific disease.Introduces pure culture techniques.