Chapter 1

Helminths

-A parasitic roundworm or flatworm

Archaea

-Consist of prokaryotic cells; lack peptidoglycan in their cell walls -Include: methanogens, extreme halophiles, and extreme thermophiles

Fungi

-Eukaryotic cells; multicellular -Obtain nutrients by absorbing organic material from their environment

Viruses

-Noncellular entities that are parasites of cells -Consist of a nucleic acid core (DNA or RNA) surrounded by a protein coat. An envelope may surround the coat

People believed all microbial diseases would be controlled by the 21st century. Name one emerging infectious disease. List three reasons why we are identifying new diseases now.

-Tuberculosis 1. New technology keeps being developed that helps identify new diseases 2. People are coming over from other countries and we are experiencing their diseases 3. The diseases are mutating

Protozoa

-Unicellular eukaryotes -Obtain nourishment by absorption or ingestion through specialized structures

Algae

-Unicellular or multicellular eukaryotes that obtain nourishment by photsynthesis -Produce oxygen and carbohydrates that are used by other organisms

Bacteria

-Unicellular organisms; no nucleus, cells are prokaryotic -Basic shapes: bacillus, coccus, spiral -Peptidoglycan cell wall; they divide by binary fission, and they may possess flagella -Can use a wide range of chemical substances for their nutrition

Jenner

Developed vaccine against smallpox

Jacob and Monod

Discovered how DNA controls protein synthesis in a cell

Fleming

Discovered penicillin

Lederberg and Tatum

Discovered that DNA can be transferred from one bacterium to another

Pasteur

Disproved spontaneous generation

Stanley

First to characterize a virus

van Leewenhoek

First to observe bacteria

Hooke

First to observe cells in plant material and name them

How did the idea of spontaneous generation come about?

In the 19th century, many scientists believed that some forms of life could arise spontaneously from nonliving matter. They would see flies coming out of manure and maggots coming our of dead animals and see microorganisms appear in liquids after a day or two.

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

It claimed that living cells can arise only from preexisting living cells, and the germ theory of disease is that microorganisms might cause disease.

Iwanowski

Observed that viruses are fliterable

Some proponents of spontaneous generation believed that air is necessary for life. The 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 placed broth in open-ended long-necked flasks and bent the neck into S-shaped curves. The contents of these flasks were then boiled and cooled. The broth in the flasks did not decay and showed no signs of life, even after months. This unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might contaminate the broth.

Lancefield

Proposed a classification system for streptococci based on antigens in their cell walls

Avery, MacLeod, and McCarty

Proved that DNA is the hereditary material

Koch

Proved that microorganisms can cause disease

Lister

Proved that microorganisms can cause disease

Virchow

Said living cells arise from preexisting cells

Berg

Showed that fragments of human or animal DNA that code for important proteins can be attached to bacterial DNA

Beadle and Tatum

Showed that genes code for enzymes

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?

They could see how dirty they were and when the didn't disinfect their hands after each patient they thought they might be transmitting infections from one patient to another. The both wanted to have a healthier environment for their patients.

Weizmann

Used bacteria to produce acetone

Ehrlich

Used to first synthetic chemotherapeutic agent

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

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

Which of the following is a scientific name? a. Mycobacterium tuberculosis b. Tubercle bacillus

a. Mycobacterium tuberculosis

Which of the following is an example of bioremeditation? 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 e. all of the above

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

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 living organisms. d. Air is necessary for living organisms. e. Microorganisms can be generated from nonliving matter.

b. Living cells can only arise from preexisting cells

Spallanzani's conclusion about spontaneous generation was challenged because Lavoister have just shown that oxygen was the vital component of air. Which of the following statements is true? a. All life requires air. b. Only disease-causing organisms require air. c. Some microbes do not require air. d. Pasteur kept air out of his biogenesis experiments. e. Lavoisier was mistaken.

c. Some microbes do not require air

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

c. decompose organic material and recycle elements

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

c. have the same shape

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.

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

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. the animal has a lowered resistance. c. a microorganism is observed in the animal. d. a microorganism is inoculated into the animal. e. microorganisms can be cultured from the animal.

d. a microorganism is inoculated into the animal.

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

e. all of the above