ch 1 humans and the microbial world

microbes

includes acellular (not made of cells) members of the microbial world

which groups are single and multicellular organisms

algae and fungi

unicellular microbes

one cell

multicellular microbes

multiple cells

microorganisms have existed for

approximately 3.5 billion years

plants, animals, modern microorganisms all evolved from..

ancestral bacteria

Antonie van Leeuwonhoek

made simple magnifying glass, studied lake water, observed “animalcules” (tiny animals)

Robert Hooke

also credited with discovery of microbes, described “microscopical mushroom” aka bread mold in 1665

Spontaneous Generation

belief that life arises from non living material

Francesco Redi

performed experiment that challenged spontaneous generation; demonstrated with rotting meat and maggots

Louis Pasteur

provided major evidence that disputed spontaneous generation, demonstrated that air is filled with microorganisms; swan necked flasks to keep broth sterile

Whose work led to the debate over spontaneous generation and led to the theory of biogenesis?

Louis Pasteur

biogenesis

living things are produced other living things

John Tyndall

found that different types of broths required different boiling times to become sterile

Who discovered that some materials contain microorganisms that are heat resistant?

Tyndall

What are the two forms of microbes that Tyndall discovered?

cells easily killed by heat AND cells that are heat resistant

Ferdinand Cohn discovered

endospores

endospores are

heat resistant form of bacteria

The Golden Age of Microbiology

born after spontaneous generation was disproved

Germ Theory of Disease

the idea that microbes cause disease; before germ theory disease was thought to be caused by supernatural, poisonous air, or body imbalance of four humors (blood phlegm, yellow bile, black bile)

normal microbiota

play role in human health: prevent disease by competing e disease causing microbes, aid in digestion,

promote development of immune system (decrease asthma, allergies), may affect brain chemistry and body weight

prokaryotic cells

do NOT contain membrane bound nucleus

Eukaryotic cells

contain membrane bound nucleus

all living things are made of cells and can be classified into what three domains?

1. bacteria (prokaryotes),

2. archaea (prokaryotes),

3. eukarya (eukaryotes)

Latin microbe names are

binomial, first part is genus (capitalized) & second part is species (not capitalized)

members of a species with important MINOR differences may be indicated with….

a strain (ex ; E. coli K12)

bacteria

single celled prokaryotes, peptidoglycan in cell wall (unique to bacteria), flagella, binary fission

shape of bacteria

coccus, bacillus, vibrio, spirillum, spirochete, pleomorphic

coccus

spherical cells

bacillus

rod shaped

vibrio

short curved rod like a comma

spirillum

a RIGID curved spiral rod

spirochete

long spiraled shaped cell flexible cell wall

pleomorphic

vary in shape

cocci that remain as pairs

diplococci

division in one plane forming long chains

chain of cocci, ex streptococcus

cocci in perpendicular and cubical packets

packet (think perfect)

cocci in random several planes, grape like

clusters

archaea

single celled prokaryotes similar in size, shape, and properties to bacteria

main difference between archaea and bacteria

chemical composition, archaea lacks peptidoglycan and the ribosomal RNA sequences are diffeent)

many archaea are extremophiles, meaning

they live in extreme conditions, ex: in salt concentration, temperature

eukarya

single celled or multicellular eukaryotes

types of eukarya

fungi, algae, protozoa, helminths

algae and protozoa are aka

protists

fungi

single celled yeasts to multicellular molds ( spores, mushrooms ) they decompose

algae

diverse group of photosynthetic eukaryotes; can be single celled or multi cellular ;, contain chloroplasts; usually in moist or water environmetns

protozoa

diverse group of single celled eukaryotes ; complex, larger than prokaryotes; no rigid cell wall; most are motile

parasitic helminths

worms that live at the expense ; ex: roundworms, tapeworms, flukes

acellular infectious agents

are non living, require host ; includes viruses, viroids, prions

viruses

nucleic acid packaged in protein coat, infects living cells (aka hosts), OBLIGATE INTRACELLULAR AGENTS, may kill host cell and remain with host and eplicate viral genetic info as host cell multiplies

viroids

consist of only of a single short piece of RNA, OBLIGATE INTRACELLULAR AGENTS, causes plant disease

prions

infectious proteins , misfolded versions of normal cellular proteins found in the brain, cells die leaving spaces in brain (spongiform encephalopathy), resistant to sterilization procedures (heat does NOT kill), ex; mad cow disease

prokaryotic domain includes

bacteria and archaea