Chapter 28

Question 1

Bacteria

Answer 1

microscopic living organisms, usually one-celled, that can be found everywhere. They can be dangerous, such as when they cause infection, or beneficial, as in the process of fermentation (such as in wine) and that of decomposition.

Question 2

Archaea

Answer 2

Any of the unicellular microorganisms that is genetically distinct from bacteria and eukaryotes, and often inhabiting extreme environmental conditions

Question 3

unicellular

Answer 3

also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell. Historically, the simple single celled organisms have sometimes been referred to as monads, specially the unicellular flagellates.

Question 4

prokaryotic

Answer 4

do not have an organized nucleus. Their DNA is kind of floating around the cell. It’s clumped up, but not inside of a nucleus. If you want to learn about cells with a nucleus, look for information on eukaryotes. And, once again, a prokaryote is a single cell or organisms that does NOT have organized nuclei.

Question 5

Microbe

Answer 5

Any of the microorganisms, especially those causing diseases or infections. Supplement. The term microbe was coined to refer collectively to the microscopic organisms, including bacteria, fungi, protozoa, and viruses.

Question 6

microbiology

Answer 6

biology of microscopic organisms, or life too small to be seen with the naked eye. Microbiology covers several disciplines, including virology (study of viruses), bacteriology (study of bacteria), mycology (study of fungi), and parasitology (study of parasites)

Question 7

universal tree

Answer 7

metaphor used to describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin’s On the Origin of Species

Question 8

tree of life

Answer 8

metaphor which expresses the idea that all life is related by common descent. Charles Darwin was the first to use this metaphor in modern biology. It had been used many times before for other purposes. The evolutionary tree shows the relationships among various biological groups.

Question 9

Monophyletic group

Answer 9

taxon (group of organisms) which forms a clade, meaning that it consists of an ancestral species and all its descendants. The term is synonymous with the uncommon term holophyly.

Question 10

kingdom

Answer 10

a taxonomic category of the highest rank, grouping together all forms of life having certain fundamental characteristics in common: in the five-kingdom classification scheme adopted by many biologists,

Question 11

phylum

Answer 11

taxonomic rank below kingdom and above class. Traditionally, in botany the term division was used instead of “phylum”, although from 1993 the International Code of Nomenclature for algae, fungi, and plants accepted the designation “phylum”.

Question 12

germ theory of disease

Answer 12

states that some diseases are caused by microorganisms. These small organisms, too small to see without magnification, invade humans, animals, and other living hosts. Their growth and reproduction within their hosts can cause a disease.

Question 13

pathogen

Answer 13

infectious agent is a biological agent that causes disease or illness to its host. The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant. However, pathogens can infect unicellular organisms from all of the biological kingdoms.

Question 14

Koch’s postulates

Answer 14

The bacteria must be present in every case of the disease. The bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

Question 15

antibiotic

Answer 15

molecules that kill, or stop the growth of, microorganisms, including both bacteria and fungi. Antibiotics that kill bacteria are called “bactericidal” Antibiotics that stop the growth of bacteria are called “bacteriostatic”

Question 16

bioremediation

Answer 16

se of biological agents, such as bacteria, fungi, or green plants, to remove or neutralize contaminants, as in polluted soil or water. Bacteria and fungi generally work by breaking down contaminants such as petroleum into less harmful substances.

Question 17

anoxic

Answer 17

areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen and are a more severe condition of hypoxia. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than .5 milligrams per litre.

Question 18

enrichment culture

Answer 18

medium with specific and known qualities that favors the growth of a particular microorganism. The enrichment culture’s environment will support the growth of a selected microorganism, while inhibiting the growth of others. … Enrichment cultures are often used for soil and fecal samples.

Question 19

direct sequencing

Answer 19

the process of determining the precise order of nucleotides within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases—adenine, guanine, cytosine, and thymine—in a strand of DNA.

Question 20

Gram-Positive bacteria

Answer 20

bacteria retain the color of the crystal violet stain in the Gram stain. This is characteristic of bacteria that have a cell wall composed of a thick layer of a particular substance (called peptidologlycan).

Question 21

Gram- Negative bacteria

Answer 21

The Gram stain is one of a large number of techniques used to characterize bacteria. In particular, a bacterial species is usually either Gram-positive (purple when stained) or Gram-negative (pink when stained). … The chemicals in the stain react with these molecules in the cell wall and result in the purple color.

Question 22

Nitrate pollution

Answer 22

Water contamination caused by the presence of excessive amounts of nitrates washed out from inorganic fertilizers (the ones most commonly sold and used). These compounds cause eutrophication and are suspected in instances of blood poisoning in infants and stomach cancer in older persons.

Question 23

Dead zone

Answer 23

are hypoxic (low-oxygen) areas in the world’s oceans and large lakes, caused by “excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water.