microorganisms and microbiology

Question 1

microorganisms

Answer 1

organisms too small to be clearly seen by the unaided eye

Question 2

prokaryotic cells

Answer 2

bacteria and archaea
their contents are not divided into compartments by membranes - open

Question 3

eukaryotic cells

Answer 3

plants, animals, fungi
have a nucleus and other membrane-bound organelles that separate some cellular materials and processes from others

Question 4

three domain system for microorganisms

Answer 4

bacteria
archaea
eukarya

Question 5

bacteria

Answer 5

• usually single-celled
• most have cell wall with peptidoglycan
• most lack a membrane-bound nucleus
• live in extreme environments (including our bodies)
• both disease causing and non-disease causing exist

Question 6

archaea

Answer 6

• distinguished from bacteria by unique rRNA sequences
• have unique membrane lipids
• many live in extreme environments
• some have unusual metabolic characteristics
• do not directly cause disease in humans

Question 7

two classifications of eukarya

Answer 7

protists
fungi

Question 8

protists

Answer 8

• unicellular, but generally larger than bacteria and archaea
• protozoa - animal like metabolism
• algae - photosynthetic

Question 9

fungi

Answer 9

• unicellular or multicellular

Question 10

viruses

Answer 10

acellular entities that must invade a host cell to multiply

Question 11

viroids

Answer 11

infectious agents composed only of ribonucleic acid

Question 12

satellites

Answer 12

composed of a nucleic acid enclosed in a protein shell
must coinfect a host cell with a virus, called a helper virus, to complete their life cycle

Question 13

prions

Answer 13

infectious agents composed only of protein, responsible for causing neurological diseases such as scrapie and mad cow disease

Question 14

ribozymes

Answer 14

catalytic RNA molecules
RNA molecules that form peptide bonds

Question 15

RNA world

Answer 15

describes the precellular stage in the evolution of life
- must of had lipid membrane formed around RNA

Question 16

evidence of RNA world hypothesis

Answer 16

• most cellular RNA in modern cells exists in and is associated with the ribosome to construct proteins
• rRNA catalyzes peptide bond formation in protein synthesis
• similar structures indicate RNA may be precursor to double stranded DNA
• the energy source of current cells is a ribonucleotide (ATP)
• RNA can regulate gene expression

Question 17

last universal common ancestor

Answer 17

• most recent organism from which all three types of life arose
• archaea and eukarya evolved independently of bacteria

Question 18

taxonomy

Answer 18

science of classifying living things
- classification
- nomenclature
- identification

Question 19

strain

Answer 19

descendants of a single, pure microbial culture
- can be characterized biochemically, morphologically, or pathogenically

Question 20

microbiology

Answer 20

study of microorganisms and the tools used for the study

Question 21

pure culture

Answer 21

aka axenic culture
isolated strain - removed from their normal habitats and grown in isolation

Question 22

francesco stelluti

Answer 22

earliest microscopic observation
bees and weeviles btw 1625 and 1630

Question 23

robert hooke

Answer 23

published drawing of the fungus Mucor in 1665

Question 24

antony van leeuwenhoek

Answer 24

first person to observe microorganisms accurately
1632-1723

Question 25

spontaneous generation

Answer 25

belief that living organisms could develop for nonliving matter - discredited by francesco redi 1626-1697 - showed maggots on decaying meat came from fly eggs

Question 26

john needham

Answer 26

based on observation that boiled hay gives rise to microorganisms - thought life from nonliving material 1713-1781

Question 27

lazzaro spallanzani

Answer 27

proved that they hay itself didn't make microorganisms if in sealed environment 1729-1799

Question 28

louis pasteur

Answer 28

- swan-neck flask experiments discredited spontaneous generation

Question 29

john tyndall

Answer 29

demonstrated that dust carries microorganisms no dust = nutrient broths remained sterile, even if directly exposed to air also provided evidence for the existence of exceptionally heat-resistant forms of bacteria - discredited spontaneous generation 1820-1893

Question 30

ferdinand cohn

Answer 30

showed heat-resistant bacteria could produce endospores - discredited spontaneous generation 1828-1989

Question 31

4 bodily-fluid humors infectious diseases were believed to be due to

Answer 31

blood, phlegm, yellow bile (choler), and black bile (melancholy)

Question 32

scientist who found early evidence for the relationship between microorganisms and disease

Answer 32

- agostine bassi (1773-1856) showed a disease of silkworms was caused by a fungus - M. J. berkeley (1803-1889) demonstrated the potato blight of ireland was casued by a protozoan - heinrich de bary (1831-1888) showed fungi caused crop disease - louis pasteur (1882-1895) demonstrated microorganisms carried out fermentation - joseph lister (1827-1912) provided indirect evidence that microorganisms were the causal agents of disease developed an antiseptic surgery system to prevent microorganisms from entering wounds

Question 33

robert koch

Answer 33

1843-1910 koch's postulates - provides the causal relationship btw a microorganisms and a specific disease - demonstrated that mycobacterium tuberculosis causes tuberculosis

Question 34

limitations of koch's postulates

Answer 34

- some organisms cannot be grown in pure culture bc they rely on host cells - lack animal model - using humans in completing the postulates is unethical - molecular and genetic evidence may replace and overcome these limits

Question 35

steps in koch's postulates

Answer 35

1. the microorganisms must be present in every case of the disease but absent from healthy organisms 2. the suspected microorganism must be isolated and grown in a pure culture 3. the same disease must result when the isolated microorganisms is inoculated into a healthy host 4. the same microorganisms must be isolated again from the diseased host

Question 36

immunological studies

Answer 36

- edward jenner (1749-1823) used vaccination procedure to protect against smallpox - emil von behring (1854-1917) and shibasaburo kitasato (1852-1931) developed antitoxins (antibodies) for diphtheria - elie metchnikoff (1845-1916) discovered first immune system cells - phagocytic cells in blood engulf bacteria