Ch 1: History Flashcards
What is microbiology?
Microbiology is the science that studies microorganisms
What are microorganisms?
Microorganisms are living things that (usually) are too small to be seen with the naked eye
What techniques does microbiology utilize?
Aseptic technique
Pure culture technique
Microscopic observation of whole organisms
A microbiologist usually first isolates a specific microorganism from a population and then cultures it
What are normal flora?
These are the harmless microorganisms found on every part of your body that normally comes in contact with outside world (deep lungs and stomach are exceptions)
Name four ways that microbes contribute to ecology
Microbes are produces—they provide energy to ecosystems, especially aquatic ecosystems
Microbes are fixers—they make nutrients available from nitrogenous compounds
Microbes are decomposers—they free up nutrients from no longer living sources
Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments
Infectious diseases are caused by what?
Microbes
How many deaths per year are caused by microbes?
200,000 per year
In 1918 20 million died from influenza
Describe spontaneous generation belief including time period
During this period (1600’s) there was a common belief that new organisms arose spontaneously from certain substances.
First proposed by Aristotle, this view persisted well into the 1800’s.
Describe the scientific method
- Observation leads to question
- Question generates hypothesis
- Hypothesis is tested through experimentation
- Results prove or disprove hypothesis
- Accepted hypothesis leads to theory/law
- Reject or modify hypothesis
What is cell theory?
All life is made of cells and all cells come from pre-existing cells
What is germ theory of disease?
States that microorganisms can invade other organisms and cause disease
What is evolutionary theory?
The idea that genetic information changes over time
What did Robert Hooke discover?
Looking in his microscope at cork, Hooke described “little boxes” or “cells”
Why was Hooke’s discovery important (1665)?
This was the beginning of Cell Theory which states all living things are composed of cells
What did Antoni van Leeuwenhoek discover (1673)?
First to observe live microorganisms in pond water
Called his discoveries “animalcules“
More animalcules in his own mouth than all people in Netherlands
What Leeuwenhoek observed are now recognized to be bacteria + protozoa
What did Francesco Redi show? What was his evidence and was the “problem” with his experiment?
Redi placed meat in jars: some sealed, some unsealed.
He showed maggots did not “arise from” decaying meat. (before microscopic observations of Leeuwenhoek)
EVIDENCE - No maggots grew on meat which was sealed in jars – they did appear on the meat in open jars
Problems with this…
Opponents claimed that AIR contained some ‘vital force’ that was necessary for life
What did John Needham try to show?
1745 - John Needham (England) boiled meat broths and poured them into covered containers;
microbes still grew after heated nutrient fluids were poured into covered containers - Needham said this was spontaneous
WHY did bacteria still grow?
It was left out and contaminated before it was covered (poor technique)
What did Lazzaro Spallanzani propose (1765)? What did Needham counter with? What was the contridiction?
(Italy)
Spallanzani proposed that microorganisms came from air getting into Needham’s samples
He found none in broth after heating in sealed containers that were not exposed to the air
Needham countered by saying:
A ‘vital force’ needed for spontaneous generation was killed by the heating and could not enter the sealed flask
Needham also used covered containers…
What was Rudolf Virchow’s contribution (1858)?
First major challenge to Spontaneous Generation
(Germany)
‘All life can arise only from preexisting, living cells’
later refined into modern Cell Theory by Schleiden & Schwann
Virchow also discovered gaps between the myelin
