microbiology quiz 1- origins

number of bacteria on a human at any given moment

> 100,000,000,000,000 (one hundred trillion)

first term used to describe microorganisms

animalcules

who coined the term “animalcules” and was the first to see them

Leeuwenhoek (1670’s)

what did Leeuwenhoek use to see the microorganisms

single lens microscope

What was the book “Micrographia”

a microscopic description of things using a compound microscope

who wrote the book “Micrographia”

Robert Hooke

Who coined the term “microorganisms”

Louis Pasteur

how old are microbes

said to be the oldest forms of life- almost as old as the earth (4 billion yrs dated from stromatolites)

what are stromatolites

layered rock formations formed by microbes that trap sediment.

what is LUCA

stands for the last universal common ancestor, LUCA was a prehistoric microbe

theory of spontaneous generation

belief that life spontaneously generated, like with divine intervention (anomalous)

when was the theory of spontaneous generation popular

200 BC to mid 19th century AD

what did Pasteur do for the theory of spontaneous generation

he debated it during his research on food spoilage

food spoilage theory

Pasteur said microorganisms were responsible for food spoilage. Proved with swan neck since microbes could not enter flask after getting stuck with divot after sterilization.

what is biogenesis

the concept that life requires descent, organisms come from pre existing organisms

what is LUCA hypothesized to have originated from

an acellular and nonliving first universal common ancestor (FUCA) - Progenote

what was the stanley miller experiment

made organic molecules from inorganic molecules in vitro experimentally using electrical sparks, gases, water, and a heat source.

what gases were in the primitive atmosphere

water, methane, ammonia, hydrogen, and carbon monoxide.

what does the virus first hypothesis say about the FUCA

says viruses were the FUCA

what did pasteur say about infectious disease causation

that microbes held a role in it

was taxonomy in the 19th century organized

no, it was completely disorganized since morphology was used exclusively

what did Carl Woese do

redefined the tree of life based on DNA sequences.

how were the 3 domains of life resolved by carl woese

by comparing rRNA sequences since they are conserved but different enough between species to place into domains.

wha are the only non microbes in the tree of life

animals and plants

Traits shared by all domains of life:

double stranded dna, rna polymerase, protein domains, cytosol

prokaryotes:

• unicellular

• less cell volume

• circular dna

eukaryotes:

• organelles and endomembrane system for compartmentalization- solves diffusion

• linear dna

• can be multi or unicellular

5 categories of microbes

1. bacteria (prok)

2. archea (prok)

3. microalgae (euk)

4. microfungi (euk)

5. protist (euk)

how many species of microbes

1 trillion, less than 0.001% identified. Bacteria is most diverse.

What implication can be made regarding infectious disease based on the results of Pasteur’s swan-neck flask experiment?

The presence and actions of microbes cause infections

Carl Woese sequenced which macromolecule to establish the domain structure of his tree of life?

DNA