MCB2010 CH. 1 Humans and the Microbial World

When considering the human body and its microbial inhabitants, we could be best described as ___.

A planet composed of various ecosystems, with an important part of these ecosystems being a population of interacting microbes

Members of which domains can be infected by viruses?

Archaea, Eukarya, Bacteria

The domains ___ and ___ are made up of prokaryotes.

Bacteria, Archaea

Using microorganisms to degrade toxic chemical spills is an example of ___.

Biodegradation

___ is the process by which microbes carry out the decomposition of harmful chemicals.

Bioremediation

The use of microorganisms to solve practical problems is the definition of ___.

Biotechnology

Which of the following are produced metabolically by microorganisms?

Cellulose Antibiotics Ethanol as a biofuel

Which of the following are manufactured by microbial fermentation?

Cheese Beer Yogurt

The "Old Friends" hypothesis suggests that ___.

Early exposure to certain microorganisms helps protect individuals from allergies, asthma, and some other diseases

An infectious disease that has become more common in the past 35 years is referred to as an ___ infectious disease (EID).

Emerging

For the name Streptococcus pyogenes, the first part (Streptococcus) indicates the ___ and gives information about the shape of the organism.

Genus

Which is true regarding scientific names?

Genus names are commonly abbreviated Scientific names are italicized or underlined

The principle that microorganisms cause certain diseases is called ___ Theory of Disease.

Germ

The term ___ refers to a multicellular parasite such as a roundworm or tapeworm.

Helminth

Prions are ___.

Infectious protein

Which of the following infectious diseases killed more people in 1918-1919 than dies in World Wars I an II combined?

Influenza

Describe a viroid

It consists of a single short piece of RNA It can infect plants

Describe the cultivation of microorganisms in the laboratory:

Less than 1% if microorganisms can be cultivated

Which defines spontaneous generation?

Life arose from non-living matter

Why do microorganisms serve as important models for studying of higher organisms?

Microorganisms have the same fundamental metabolic and genetic properties as other organisms

In research, bacteria often serves as ___, meaning that they are studied as a means to better understand processes fundamental to higher life forms.

Model organisms

Compared to the range of types of plants and animals, microbes as a group are ___.

More diverse

In general, disease-causing organisms are referred to as which of the following?

Pathogens

Infectious diseases can reemerge as a result of ___.

Pathogens becoming resistant to antimicrobial medications Parents refusing to vaccinate their children

Which if the following diseases killed one-third of the population of Europe in the 14th century?

Plague

Which is a paralysis-inducing disease that has been nearly eliminated due to vaccination?

Polio

Which of the following cannot reproduce independently?

Prions Viroids

Like plants, some microorganisms ___.

Produce oxygen and are photosynthetic

Eukaryotic organisms can be ______.

Single-celled Multi-celled

Algae are ___.

Single-celled, photosynthetic eukaryotes Multicellular, photosynthetic eukaryotes

Prions are misfolded proteins that cause ___.

The normal version of the protein to also misfold

Consider the Human Microbiome Project begun in 2007. The term "microbiome" has which two overlapping meanings?

The total genetic content of a microbial community The microbial community itself

Solid, repeatable, extensive amounts of scientific evidence can lead to which of the following?

Theory

Some scientists were skeptical of Pasteur's results because they ___.

They could not reproduce his results

Which of the following describes how fungi gain energy?

They degrade organic materials with enzymes

Because they are often caused by a Helicobacter pylori infection, most stomach ulcers are treatable with ___.

Antibiotics

Unlike the other organisms, most ___ have cell walls that contain peptidoglycan.

Bacteria

Which microorganisms lack a membrane-bound nucleus?

Bacteria Archaea

Which diseases are due to organisms "jumping" from a natural animal host to using humans as a host?

Emerging

Which cell type is usually larger in size?

Eukaryotic

Organisms that populate the human body and which protect it from disease are termed ___.

Normal microbiota

Which of the following is/are true regarding viruses?

Outside of host cells, viruses are inactive Viruses can only multiply within host cells

All of the following are factors that account for the emergence of new diseases in developed countries EXCEPT ___.

Parents don't have their children vaccinated. This is a reason for resurgence of old diseases.

Algae and protozoa are also referred to as ____, a diverse group that falls within the domain Eukarya.

Protists

Lazzaro Spallanzani's experiments in the 1700s showed that flasks of broths had been boiled for long periods of time and sealed ___.

Remained sterile

When scientist share their work in scientific journals, they are communicating the ___.

Results, conclusions, and methods

Although archaea and bacteria differ in a number of important characteristics, it was ultimately significant differences in their ___ that provided the basis for separating the two groups of prokaryotes into different domains.

Ribosomal RNA sequences

Without microorganisms, substances required for human life such as O2 and organic nitrogen would ___.

Run out

The species names of Escherichia coli and Escherichia vulneris reflect the ___.

Site where the organism may be found

Describe characteristics of bacteria:

Some obtain energy from sources not used by animals or plants Some obtain energy from food similar to what humans eat Some obtain energy from sunlight Shapes include rod, spherical, and spiral They multiply by binary fission

The Golden Age of Microbiology occurred soon after ___.

Spontaneous generation was disproved, and led to a time when the field of microbiology blossomed

The term staphylococci is an informal name for species of the genus ___.

Staphylococcus

If cattle, sheep, and deer had a microbe-free digestive tract, they would ___.

Starve

What is the only shared feature of all microbes?

Small size

Which of the following can be infected by viruses?

Bacteria Plants Protists Fungi Animals

Which type of microorganisms have cells that lack membrane-bound organelles?

Bacteria Archaea

John Tyndall's experiments in 1800s showed that live microorganisms remained in some broths even after they had been boiled for 5 hours. This observation can be explained by the presence of a heat-resistant form of bacteria called an ___.

Endospore

John Needham's experiments showed that microorganisms grew in broths that had been boiled and sealed with a cork. Later experiments showed that wither the cork did not properly keep out microbes, or the growth was due to ___.

Endospores that survived the boiling temperatures

Characteristics of archaea that are similar to bacteria include their ___.

Energy sources used Shapes Method of multiplication Prokaryotic cell structure

___ is the domain of organisms whose cells have a nucleus and various organelles.

Eukarya

Fungi, algae, protozoa, and helminths are all ___.

Eukaryotes

Archaea are commonly found in which roles or environments?

Hot Springs Oceans Soils Extremely salty water such as the Great Salt Lake and Dead Sea

The microscopic filaments of molds are called

Hyphae

Describe the characteristics of protozoa:

Most are motile Can be found in terrestrial and aquatic habits Ingest organic material as their main food source

To indicate slight differences, members of the same species may be given ___ designations.

Strain

Where are algae most likely to be found?

Surface of oceans, lakes, and streams Moist terrestrial habitats

Unlike newspaper or blog articles, communications about scientific discoveries in respected scientific journals include ___.

1. Information about the methods used in the experiment (Scientific journals use a review process in which experts in the field read the communication, and then suggest ways to improve the experiment.) 2. A pre-publication review process (Newspaper and blog articles often report conclusions, but without the detailed information that allows readers to determine the validity of the conclusions) 3. detailed information that led to the conclusions (Scientific journals include detailed methods, so that other scientists can attempt to replicate the experiment)

The scientific process involves a series of steps. Rank the four steps of this process in order.

1. Make an observation about something and ask a question about the situation 2. Develop an explanation and then devise an experiment to test this explanation 3. Collect data from the experiment 4. Draw a conclusion

True or False: Travelers and immigrants can contribute to disease emergence.

True

True or False: We could not survive without microorganisms, but they can also be harmful.

True

Unlike the term microorganism, the word microbe also includes ___.

Viruses (Not microorganisms)

Why were Louis Pasteur's experiments with swan-necked flasks so important in helping disprove the theory of spontaneous generation?

They ended arguments that a "vital force" was necessary for spontaneous generation, while preventing contamination from microbes in the air

A scientific experiment includes a component that rules out alternative explanations of the results by showing that the only feature that varied in the experiment was the characteristic being tested. The component that does this is called a ___.

Control