Microbiology, Exam 1: Ch 1

Louis Pasteur

"Father of modern microbiology" demonstrated air is filled with microorganisms Swan-neck flask & boiling broth experiment. Ended arguments that unheated air or broths contained "vital force" necessary for spontaneous generation

Influenza

1918-1919 killed 20 and 40 million people Killed more Americans than died in WWI, WWII, Korean, Vietnam, and Iraq wars combined

Like plants, some microorganisms 1. Convert N2 into an organic form 2. Produce oxygen (O2) 3. Are photosynthetic

2 and 3

How many microbes does a person shed in one hour?

37 million microbes/hour

If while investigating spontaneous generation, Pasteur had his laboratory located in a stable A. The results would, most likely, have supported the idea of spontaneous generation. B. The results would, most likely, have not supported the idea of spontaneous generation. C. This would have had no effect on his results. D. This would have shown his love of horses.

A.

Normal Microbiota or Normal Flora or Microbiome

All surfaces of large living microorganisms that are populated by microorganisms

The Golden Age of Microbiology

Beginning with Pasteur's work, discoveries included the relationship between microbes and disease, immunity, fermentation, and antimicrobial drugs

John Needham

Boiled nutrient broth briefly and then poured it into cork-sealed flasks & microbial growth resulted (1745)

Lazzaro Spallanzani

Boiled nutrient solutions for longer periods and melted flask mouth & no microbial growth resulted (1765)

Which does not describe protozoa correctly? A. Single-celled prokaryotes B. Ingest inorganic materials as main food source C. Most are motile D. Found in terrestrial and aquatic habitats

C and D

Decomposers of materials

Cellulose degraded in the environment and in the digestive tracts of ruminants

Emerging Infectious Diseases

Changing lifestyles increase opportunities to spread Changes in population structures Horizontal gene transfers, mutations of infectious agents previously unable to infect humans Increased movement Ecological changes

Viruses

Consist of either DNA or RNA, surrounded by a protein coat. Obligate intracellular agents that use the machinery and nutrients of host cells to replicate

Viroids

Consist only of RNA no protein coat. Obligate intracellular agents that use the machinery and nutrients of host cells to replicate

Prions (Infectious Proteins)

Consist only of proteins, no DNA or RNA. Misfolded versions of normal cellular proteins that cause the normal versions to misfold

All of the following are factors that account for the emergence of new diseases in developed countries except A. Change in microbial DNA B. Changing lifestyles of humans C. Suburban expansion into rural areas D. Parents don't have their children vaccinated

D.

Pathogen-Host Interactions

Damage tissues Disease symptoms

Biodegradation

Degrade PCBs, DDT, trichloroethylene and others Help clean up oil spills

Which statement best describes bacteria? A. Unicellular, having cell wall of cellulose and a nucleus B. Multicellular, having cell wall of cellulose and no nucleus C. Unicellular, having cell wall of peptidoglycan and a nucleus D. Multicellular, having cell wall of peptidoglycan and no nucleus E. Unicellular, having cell wall of peptidoglycan and no nucleus

E.

John Tyndall

English physicist showed sterilizing broths required different times

Scientific Theory

Explanation supported by a large amount of evidence

Endospores

Form of bacteria extremely resistant to heat

Francesco Redi

Formed experiment that proved worms on rotting meat came from eggs of flies landing on meat (1668)

Microorganisms

Foundation for all life on earth Have existed for ~3.5 billion years Plants, animals, & modern microorganisms all evolved from ancestral bacteria

Eukarya members

Fungi Algae Protozoa Helminths (roundworms, tapeworms)

Ferdinand Cohn

German botanist discovered endospores in same year as John Tyndall's demonstration

Obligate Intracellular Parasites

Inactive outside of hosts infect and reproduce in living cells Multiply using host machinery and materials

Genetic Engineering

Introduction of genes into another organism Disease-resistant plants Production of medications Cure genetic diseases

Scientific Names

Latin Binomial System of Nomenclature: two words Genus is capitalized and species is lowercase Always italicized or underlined

The Scientific Method

Make an observation Develop a testable explanation called a hypothesis Design experiments to test the hypothesis Do the experiment, collect and analyze data Draw a conclusion Communicate methods, results and conclusions Reproduce results

In the 1700s, Lazzaro Spallanzani boiled and sealed flasks of broth and then looked for growth. He found none. Based on the results of his experiments, he concluded that

Microbes in the air could enter open flasks

Germ Theory of Disease

Microorganisms may be the cause of certain diseases

Impact of Microorganisms

Most microbes are beneficial/harmless We cant survive without them. Benefits (nitrogen fixation, oxygen production, degradation of materials) Killed more people than have ever been killed in wars & have even been used as weapons and could be used in bioterrorism attacks

Robert Hooke

Observed 'microscopical mushroom' in 1665

Microorganisms in the Environment

Oxygen production through photosynthesis Nitrogen fixation Recycling of nutrients Decomposers of material

Beneficial effect of human microbiomes

Prevent diseases by competing with pathogens Promote the development of immune system response Help in digestion

Bacteria

Prokaryotic, single-celled organisms with a peptidoglycan cell wall and living on a diverse source of energy

Archaea

Prokaryotic, single-celled organisms without a peptidoglycan cell and living in extreme environments. More like Eukaryotes than Bacteria

Antony Van Leeuwenhoek

Reported 'animalcules' in 1674 & birthed the science of microbiology

Algae

Single or multiple cellular eukaryotes with cellulose cell walls carrying out photosynthesis and producing O2.

Fungi

Single or multiple cellular eukaryotes with chitin cell walls using organic chemical for energy, vegetative mycelia consisting of filamental hyphae

Protozoa

Unicellular eukaryotes with no cell walls Absorb or ingest organic chemicals May be motile via pseudopods, cilia, or flagella

Biotechnology

Use of microbiological and biochemical techniques to solve practical problems

Bioremediation

Using microorganisms to hasten decay of pollutants

Re-emerging (Resurgent) diseases

Vaccination can become victim of own success People fear vaccines more than the diseases Overuse of antibiotics Increased resistance to antimicrobials

Parasitic Helminths

Worms that live at the expense of a host Adult stage can usually be seen without magnification Eggs and larvae are microscopic Include roundworms, tapeworms,and flukes

Microbes in food production

Yeast used to bake bread Fermentation of grains to produce beer & of milk to make yogurt, cheese, buttermilk

Plague

~1/3 of population of Europe died between 1346-1350 Today, fewer than 100 die worldwide Control of rodent population harboring bacterium Antibiotics available

Smallpox

~10 million deaths over 4,000 years Devastating on unexposed populations Worldwide eradication attempts eliminated disease No reported cases since 1977

Challenges in the United States each year

~750 million infections ~200,000 deaths Cost in tens of billions of dollars