Microbiology An Evolving Science Ch. 1

Agar

A polymer of galactose that is used as a gelling agent.

Antibiotic

A molecule that can kill or inhibit the growth of selected microorganisms.

Archaea

One of the three domains of life, consisting of organisms with a last common ancestor not shared with members of Bacteria or Eukarya. Organisms are prokaryotic (lacking nuclei, unlike eukaryotes) and possess ether-linked phospholipid membranes (unlike bac

Archaeon

pl. archaea A prokaryotic organism that is a member of the domain Archaea, distinct from bacteria and eukaryotes.

Aseptic

Free of microbes.

Autoclave

A device that uses pressurized steam to sterilize materials by raising the temperature above the boiling point of water at standard pressure.

Bacteria

One of the three domains of life, consisting of organisms with a last common ancestor not shared with members of Archaea or Eukarya. Organisms are prokaryotic (lacking nuclei, unlike eukaryotes) and possess ester-linked phospholipid membranes (unlike arch

Bacterium

pl. bacteria A prokaryotic organism that is a member of the domain Bacteria.

Biofilm

A community of microbes growing on a solid surface.

Chain of infection

The serial passage of a pathogenic organism from an infected individual to an uninfected individual, thus transmitting disease.

Chemiosmotic theory

A theory stating that the products of oxidative metabolism store their energy in an electrochemical gradient that can drive cell processes such as ATP synthesis.

Chemolithotroph

An organism that oxidizes inorganic compounds to yield energy and reduce carbon dioxide.

Colony

A visible cluster of microbes on a plate, all derived from a single founding microbe.

DNA sequencing

A technique to determine the order of bases in a DNA sample.

Electron microscope

A microscope that obtains high resolution and magnification by focusing electron beams on samples using magnetic lenses.

Endosymbiont

An organism that lives as a symbiont inside another organism.

Enrichment culture

The use of selective growth media to allow only certain microbes to grow.

Eukarya

One of the three domains of life, consisting of organisms with a last common ancestor not shared with members of Archaea or Bacteria. Cells possess nuclei, unlike cells of bacteria and archaea.

Eukaryote

An organism whose cells contain a nucleus. All eukaryotes are members of the domain Eukarya.

Fermentation

Also called fermentative metabolism. The production of ATP via substrate-level phosphorylation, using organic compounds as both electron donors and electron acceptors.

Genome

The complete genetic content of an organism. The sequence of all the nucleotides in a haploid set of chromosomes.

Germ theory of disease

The theory that many diseases are caused by microbes.

Kochs postulates

Four criteria that should be met for a microbe to be designated the causative agent of an infectious disease.

Lithotroph

An organism that oxidizes inorganic compounds to yield energy and reduce carbon dioxide.

Microbe

An organism or virus too small to be seen with the unaided human eye.

Monophyletic

Diverging from a common ancestor.

Nitrogen fixation

The ability of some prokaryotes to reduce inorganic diatomic nitrogen gas (N2) to two molecules of ammonium ion (2 NH4+).

Petri dish

Also called pour plate. A round dish with vertical walls covered by an inverted dish of slightly larger diameter. The smaller dish can be filled with a substrate for growing microbes.

Photosynthesis

The metabolic ability to absorb and convert solar energy into chemical energy for biosynthesis; a precise definition includes CO2 fixation.

Polyphyletic

Having multiple evolutionary origins.

Prokaryote

An organism whose cell or cells lack a nucleus; includes both bacteria and archaea.

Pure culture

A culture containing only a single strain or species of microorganism. A large number of microorganisms all descended from a single individual cell.

Spontaneous generation

The theory, much debated in the nineteenth century, that under current Earth conditions life can arise spontaneously from nonliving matter.

Ultracentrifuge

A machine that exposes samples to high centrifugal forces and can be used to separate subcellular components.

Vaccination

Exposure of an individual to a weakened version of a microbe to provoke immunity and prevent development of disease upon reexposure.

Virus

A non-cellular particle containing a genome that can replicate only inside a cell.

Microbiology

the study of microscopic organisms

What are the different types of microbes?

Cellular-bacteria, algae, protozoan, fungi
Acellular-virus, prion, viroids

What is the unit of measurement for microbes?

micrometer
.001 mm
10^-6 meter

What are Koch's postulates?

1. Suspected agent is only found in sick individual, not a healthy individual.
2. Suspected agent must be able to be isolated from the sick individual and grown in pure form.
3. The suspected agent must be introduced to a healthy individual and produce th

When can we not satisfy Koch's postulates?

-Individuals may carry a pathogen, but not exhibit sickness (carrier).
-There is more than one individual responsible for the disease.
-Lack of an appropriate experimental host.
-Organism itself does not cause disease, but a gene that it carries is respon

What are roles that microbes play that affect human activities?

Medicine-antibiotics, sickness
Food-fermentation
Industry
Environment

What were the original 5 kingdom system based on?

Cell structure and mode of nutrition

What were the original 5 kingdoms?

Monera, protista, fungi, plants, animals

What is the 3 domain system based on?

Phylogenetic analysis of 16 SrRNA

What re the 3 domains?

Eucarya, Bacteria, Archaea

What is the endosymbiotic theory?

Mitochondria and chloroplasts in eukaryotic cells are a result of endosymbiosisfrom prokaryotic cells engulfed by proto-eukaryotes. M and C provide energy, host provides protection.

What are the contributions of Leuwenhoek?

Designed simple microscopes, described microorganisms, scientific process of verification.

What are the contributions of Pasteur?

Showed that providing oxygen does not enable spontaneous generation with swan neck flask, discovered that specific types of microbes yield different products due to the metabolic properties of the organism, developed pastuerization, microbial basis of fer

What are the contributions of Koch?

Koch's postulates, pure culture technique, culture of organisms on agar, germ theory

Pasteurization

partial sterilization of foods at a temperature that destroys harmful microorganisms without major changes in the chemistry of the food

Vaccine

immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies

Antibody

a disease-fighting protein created by the immune system in response to the presence of a specific antigen

Antigen

A protein that, when introduced in the blood, triggers the production of an antibody

Attenuation

dilution or weakening of virulence of a microorganism, reducing or abolishing pathogenicity

Pathogen

a virus or organism that can cause disease

Humoral immunity

immunity against antigens and pathogens in the body fluids.

Cellular immunity

an immune response from the direct action of immune cells

Endosymbiosis

a mutually beneficial relationship in which one organism lives within another

Domain

most inclusive taxonomic group, larger than kingdom; three exist - bacteria, archaea, eukaryota