Chapter 1 &2 W1 Flashcards
what is a bacterium/bacteria?
A prokaryotic organism that is a member of the domain
Bacteria, distinct from archaea and eukaryotes.
-cells that lack a nucleus
what is antibiotics?
a chemical that kills or slows the growth of bacterial pathogens
must of the oxygen we breathe is released by ___?
cyanobacteria and algae
what is a microbe?
a living organism that requires a microscope to be seen- cannot be seen by the human naked eye
-ranges in size from millimetres (mm) down to 0.2 micrometer (um) and verses can sometimes be tenfolds smaller
what is a cell?
a cell is the smallest unit of life composed of a membrane-enclosed compartment of water solution containing molecules that carry out metabolism
what is a pathogen?
A bacterial, viral, fungal, protozoan, or helminthic agent of disease; among health professionals, pathogens typically are limited to bacteria, viruses, and fungi
- the causative agent of disease. often referred to as “germs”
- remain the cause of human morality
what is a genome?
- the total DNA content of an organism
- viral genomes can be RNA or DNA
what are prokaryotes?
- has no true “nucleus” or nuclear membrane
- prokaryotes include bacteria and archaea
what is a eukaryotic?
a microbial cell with a nucleus
- includes fungi, protozoa, and algae
- parasitic protozoa and fungi may infect humans
what is an algae?
A microbial eukaryote that contains chloroplasts and conducts photosynthesis
-overgrowth of algae causes “algal blooms” that poison fish
what is a protozoa?
a motile heterotrophs (consuming organic food), usually single-celled that is not fungus
what is fungi/fungus?
heterotrophic organisms that are usually nonmotile and grow by absorbing nutrients from their surroundings. fungi may grow as single cells (yeast) or as filaments (bread mold) or they may for complex structures such as mushrooms.
some fungi cause infections, esp w/ people w/ depressed immune system
what is a parasite?
Any bacterium, virus, fungus, protozoan (protist), or helminth that colonizes and harms its host; the term commonly refers to protozoa and to invertebrates.
what is a virus?
a noncellular microbe
-contains genetic material (DNA and RNA) that takes over the metabolism of a cell to generate more virus particles
what is archaea?
nonbacterial cells that lack a nucleus (prokaryotes)
-does not cause disease
what is spontaneous generation?
the theory that living microbes can arise spontaneously w/out parental organisms
what did Lazzaro Spallanzani do?
showed us that microbes arise from preexisting microbes and demonstrated that heat sterilization can prevent microbial growth
what did Rober Hooke and Antonio van Leeuwenhoek do?
were the first to record observations of microbes through simple microscopes
what did Louis Pasteur do?
discovered the microbial basis of fermentation. he showed that supplying oxygen dose not enable spontaneous generation
what did John Tyndall do?
showed us that repeated cycles of heat are necessary to eliminate spores formed by certain kinds of bacteria
what is the germ theory of disease?
holds that specific diseases are caused by specific kinds of microbes
what is chain of infection?
-factors that affect the spread of disease, which includes the organisms, reservoir, mode of transmission, and host
what is a pure culture?
a culture grown from a single “parental” cell
what are colonies?
-a visible cluster of microbes on a plate, all derived from a single founding microbe.
what is a petri dish?
-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
what are the 4 Koch’s postulates consist of?
- the microbe is found in all cases of the disease but is absent from healthy individuals
- the microbe is isolated from the disease host and grown in pure cultures
- when the microbe is introduced into a healthy susceptible host, the same disease occurs
- the same strain of microbe is obtained from the newly diseased host
what is an antiseptic agent?
a chemical that kills microbes on living tissues
who established the practice of vaccines?
Edward Jenner- inoculation of cowpox to prevent smallpox
what is pathogenicity?
the ability of the organism to cause disease
what is colonization?
-refers to the ability of the microbe to stay attached to the body surface and replicate.
disease occurs when?
pt develops symptoms
what is acute infection?
Symptoms develop and resolve rapidly.
-The common cold, strep throat etc.
what is chronic infection?
- involves symptoms that develop gradually and resolve slowly.
- tuberculosis for example
what is a primary pathogen?
- likely to cause disease after infection in a healthy host.
- Rapidly reproduce/increase in number
- Moderate to high virulence (severity increases)
what is opportunistic pathogens?
-are less likely to cause disease in a healthy host.
Low virulence
what dose virulence mean?
describes the level of harm caused by a pathogen following infection
-virulence can be measured by lethal dose 50% (LD50) or infectious dose (LD50)
what is invasion?
the entry of a pathogen into a living cell, where it then lives
what is invasiveness?
the ability of a bacterial pathogen to spread rapidly through tissues
what is host range?
refers to the animals a pathogen can infect and produce disease in.
-some organisms can infect only one type of host to produce disease
what is a narrow host range?
Salmonella enterica serovar Typhi infects humans only.