Chapter 1 Study Questions

 

 

How did the idea of spontaneous generation come about?

More than 100 years ago, people commonly believed that toads, snakes, and mice were born of moist soil.

 

Some proponents of spontaneous generation believed that air is necessary for life.  They thought that Spallanzani did not really disprove spontaneous generation because he hermetically sealed his flasks to keep air out.  How did Pasteur’s experiments address the air question without allowing the microbes in the air to ruin his experiment?

Pasteur boiled broth in flasks with S-shaped necks so that air was able to access the broth but microbes in the air would not.

 

Briefly state the role played by microorganism in each of the following:

Biological control of pests-microbial insect control used instead of chemical insect control help the environment by not upsetting the ecological balance

Recycling of elements-microorganisms convert chemical elements into forms which are useful to other organisms

Normal microbiota-natural flora within our bodies which benefit us-kept in check my mucous membranes, stomach acid, white blood cells, interferons, cilia, and skin.

Sewage treatment-bacteria convert harmful liquid and organic materials including microbes into by-products such as CO2, nitrates, phosphates, sulfates, ammonia, hydrogen sulfide, and methane.

Human insulin production-recombinant (hybrid) DNA is inserted into bacteria then used to make large quantities

Vaccine production-cultures of avirulent microorganisms are used for preventive inoculation

 

Into which field of microbiology would the following scientists fit?

            Studies biodegradation of toxic wastes-Microbial ecology

            Studies the causative agent of Hantavirus pulmonary syndrome-Virology

            Studies the production of human proteins by bacteria-Microbial genetics

Studies the symptoms of AIDS-Immunology

Studies the production of toxin by E. coli- Microbial physiology

Studies the life cycle of Cryptosporidium-Microbial biology

Develops gene therapy for a disease-Biotechnology

Studies the fungus Candida albicans-Mycology

 

Match the following people to their contribution toward the advancement of microbiology.

Avery, MacLeod, and McCarty-(l) Proved that DNA is the hereditary material

Beadle and Tatum-(d) Discovered how DNA controls protein synthesis in a cell

Berg-(p) Spliced animal DNA to bacterial DNA

Dubos-(b) Discovered antibiotics produced by bacteria

Ehrlich-® Proposed first synthetic chemotherapeutic agent

Fleming-(d) Discovered penicillin

Hooke-(j) First to observe cells in plant material and name them

Iwanowski-(k) Observed that viruses are filterable

Jacob and Monod-© Discovered how DNA controls protein synthesis in a cell

Jenner-(a) Developed vaccine against smallpox

Koch-(m) Proved that microorganisms can cause disease

Lancefield-(s) Proposed a classification system for streptococci based on antigens in their cell walls

Lederberg and Tatum-(e) Discovered that DNA can be transferred from one bacterium to another

Lister-(h) First to use disinfectants in surgical procedures

Pasteur-(f) Disproved spontaneous generation

Stanley-(g) First to characterize a virus

Van Leeuwenhoek-(i) First to observe bacteria

Virchow-(n) Said living cells arise from preexisting cells

Weizmann-(q) Used bacteria to produce acetone

 

The genus name of a bacterium is “erwinia” and the specific epithet is “carotovora.”  Write the scientific name of this organism correctly. Using this name as an example, explain how scientific names are chosen.

Erwinia carotovora [Genus epithet (family)]

 

Match the following microorganism to their descriptions.

            Archaea-         Prokaryote without peptidoglycan cell wall

            Algae-             Cell wall made of cellulose; photosynthetic

            Bacteria-        Cell wall made of peptidoglycan

            Fungi-             Cell wall made of chitin

            Helminths-      Multicellular animals

            Protozoa-        Complex cell structure lacking a cell wall

Viruses-          Not composed of cells

 

 

 

Which of the following is a scientific name?

a. Mycobacterium tuberculosis

b. Tubercle bacillus

 

Which of the following is not a characteristic of bacteria?

a. are prokaryotic

b. have peptidoglycan cell walls

c. have the same shape

d. grow by binary fission

e. have the ability to move

 

Which of the following is the most important element of Koch’s germ theory of disease?  The animal shows disease symptoms when

a. the animal has been in contact with a sick animal.

b. a microorganism is observed in the animal.

c. a microorganism is inoculated into the animal.

d. microorganism can be cultured from the animal.

 

Recombinant DNA is

a. DNA in bacteria.

b. the study of how genes work.

c. the DNA resulting when genes of two different organisms are mixed.

d. the use of bacteria in the production of foods.

e. The production of proteins by genes.

 

Which of the following statements is the best definition of biogenesis?

a. Nonliving matter gives rise to living organisms.

b. Living cells can only arise from preexisting cells.

c. A vital force is necessary for life.

d. Air is necessary for living organisms.

e. Microorganisms can be generated from nonliving matter.

 

Which of the following is a beneficial activity of microorganisms?

a. Some microorganisms are used as food for humans.

b. Some microorganisms use carbon dioxide.

c. Some microorganisms provide nitrogen for plant growth.

d. Some microorganisms are used in sewage treatment processes

e. all of the above

 

It has been said that bacteria are essential for the existence of life on Earth.  Which of the following would be the essential function performed by bacteria?

a. control insect populations

b. directly provide food for humans

c. decompose organic material and recycle elements

d. cause disease

e. produce human growth hormones such as insulin

 

Which of the following is an example of bioremediation?

a. application of oil-degrading bacteria to an oil spill

b. application of bacteria to a crop to prevent frost damage

c. fixation of gaseous nitrogen into usable nitrogen

d. production by bacteria of a human protein such as interferon

 

Spallanzani’s conclusion about spontaneous generation was challenged because Lavoisier had just shown that oxygen was the vital component of air.  Which of the following statements is true?

All life requires air.

Only disease-causing organisms require air.

Some microbes do not require air.

Pasteur kept air out of his biogenesis experiments.

Lavoisier was mistaken.

 

Which of the following statements about E. coli is not true?

a. E. coli was the first disease causing bacterium identified by Koch.

b. E. coli is part of the normal microbiota of humans.

c. E. coli is beneficial in human intestines.

d. A disease-causing strain of E. coli causes bloody diarrhea.

e. none of the above

 

 

Critical Thinking

 

How did the theory of biogenesis led the way for the germ theory of disease?

Koch would then be able to hypothesize what may be causing a disease (a living organism) enabling him to conjecture what he should observe in a sick host.

 

Even though the germ theory of disease was not demonstrated until 1876, why did Semmelweis (1840) and Lister (1867) argue for the use of aseptic techniques?

Though the theory was not completely known, Semmelweis and Lister observed healthier or more positive results from their patients with their new procedures.

 

Find at least three supermarket products made by microorganisms. (Hint: The label will state the scientific name of the organism or include the word culture, fermented, or brewed.)

Yogurt, beer, cheese.

 

People believed all microbial disease would be controlled during the twentieth century. List three reasons why we are identifying new diseases now.

Microorganisms are ubiquitous; it would take a great effort to catalogue all the species.

Microorganisms mutate into different strains; thus new diseases are created.

With the leaps of technology, people may now engineer new strains.

 

 

Clinical Applications

 

The prevalence of arthritis in the United States is 1 in 100.000 children.  However, 1 in 10 children in Lyme, Connecticut, developed arthritis between June and September in 1973.  Allen Steere, a rheumatologist at Yale University, investigated the cases in Lyme and found that 25% if the patients remembered having a skin rash during their arthritic episode and that the disease was treatable with penicillin.  Steere concluded that this was a new infectious disease and did not have an environmental, genetic, or immunologic cause.

What was the factor that caused Steere to reach his conclusion?

Penecillin is an antibiotic; if it was used successfully for treatment, then a microorganism was responsible for the symptoms.

What is the disease?

Lyme Disease

Why was the disease more prevalent between June and September?

With the warmer summer climate in the New England region and lack of school, children would play outside.  The pathogen Borrelia burgdorferi is carried by ticks located outside where children play.

 

In 1864, Lister observed that patients recovered completely from simple fractures, but compound fractures had “disastrous consequences.”  He knew that the application of phenol (carbolic acid) to fields in the town of Carlisle prevented cattle disease.  In 1864, Lister treated compound fractures with phenol, and his patients recovered without complications.  How was Lister influenced by Pasteur’s work?  Why was Koch’s work still needed?

Pasteur’s work gave evidence that air itself was not responsible for such phenomena as rotting food and abnormal growths.  Inspired by this, Lister took it one step further in that what was responsible could be contained or destroyed.  Theorizing that phenol stifled such a cause that resulted in cattle disease, Lister applied this to patients with compound fractures.  Although Lister was able to come up with procedures to increase healthy recoveries of such patients, Koch’s work was still necessary to actually identify microorganisms which caused disease.