Chapter 28 Flashcards
Bacteria
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.
Archaea
Any of the unicellular microorganisms that is genetically distinct from bacteria and eukaryotes, and often inhabiting extreme environmental conditions
unicellular
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.
prokaryotic
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.
Microbe
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.
microbiology
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)
universal tree
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
tree of life
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.
Monophyletic group
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.
kingdom
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,
phylum
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”.
germ theory of disease
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.
pathogen
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.
Koch’s postulates
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.
antibiotic
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”
bioremediation
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.
anoxic
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.
enrichment culture
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.
direct sequencing
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.
Gram-Positive bacteria
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).
Gram- Negative bacteria
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.
Nitrate pollution
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.
Dead zone
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.
