microbio chapter 1

Question 1

Antoni Van Leeuwenhoek

Answer 1

• first to understand microscopic/microorganisms
• began using simple microscopes
• examined water and saw fungi, algae, and bacteria, called them “animalcules”
  -animalcules were called microorganisms by the end of the 19th century

Question 2

Carolus Linnaeus

Answer 2

• developed taxonomic system
• six categories

Question 3

What are the six categories of Carolus Linnaeus’s taxonomic system

Answer 3

1. fungi 2. protozoa 3. algae 4. bacteria 5. archaea 6. small multicellular animals

Question 4

Fungi, protozoa, algae

Answer 4

eukaryotic but microorganisms

Question 5

Bacteria and Archaea

Answer 5

prokaryotic cells and microorganisms

Question 6

Archaea

Answer 6

-more closely related to eukaryotes but look like bacteria
-normally live in harsh environments

Question 7

Fungi characteristics

Answer 7

• eukaryotic, contain a nucleus
• have cell walls and obtain food from other organisms
• composed of molds: multicellular, grow as long filaments that intertwine
  - reproduce sexually and asexually
• composed of yeasts: unicellular, oval or round
  - repoduce asexually though budding, some produce sexual spores

Question 8

Protozoa characteristics

Answer 8

• single-celled eukaryotes
• similar to animals in nutritional needs, cell structure
  -live freely in water or animal hosts
• most asexual, some sexual

Question 9

How are protozoa categorized

Answer 9

• by their locomotion
• pseudopodia: cell extensions that flow in direction of travel
• cilia: numerous, short, protrusions that propel through regular beating
  -flagella: fewer than cilia, but longer and more whiplike

Question 10

Algae characteristics

Answer 10

• uni or multicellular photosynthetic organisms
• categorized on basis of pigmentation, storage products, and cell wall composition
• large algae= seaweed and kelp (derive agar)
  -unicellular algae are common in freshwater, streams, lakes, pones, oceans
• serve as major food for aquatic/marine animals

Question 11

Bacteria and Archaea characteristics

Answer 11

• unicellular and lack nucleus
• much smaller than eukaryotes (= mitochondria size)
• asexual reproduction
• bacteria cell walls are composed of peptidoglycan
• archaea cell walls lack peptidoglycan
• live in almost every habitat that contains enough moisture (pairs, clusters, single, chains)
• 1 single bacteria cells can contain 100s of viruses

Question 12

What is the difference between the cell walls of bacteria and archaea

Answer 12

Bacteria cell walls are composed of peptidoglycan and archaea cell walls are not

Question 13

During the Golden age of microbio, what four questions did scientists want to answer?

Answer 13

1. Is spontaneous generation of microbial life possible
2. What causes fermentation?
3. What causes disease?
4. How can we prevent infection and disease?

Question 14

Aristotle

Answer 14

• proposed spontaneous generation

Question 15

What is spontaneous generation?

Answer 15

The idea that living things can arise from nonliving/inanimate matter (350BC)

Question 16

Francisco Redi

Answer 16

• late 1600s
• demonstrated that when decaying meat was isolated from fleas, no maggots developed
• as a result, scientists began to doubt Aristotle (used science to change ideas over a long period of time)
• dependent variable: maggots or no maggots
• independent variable: uncovered, covered, or gauzed covered jar

Question 17

Needham

Answer 17

• expanded on Redi’s experiment but included bacteria after Leeuwenhoek’s discovery of them
• believed microbes did arise spontaneously
• boiled beef gravy and placed in jars (covered and uncovered)
• covered jar still appeared cloudy
• led to ‘proof’ of spontaneous generation
• later found out that he did not boil beef gravy long enough to kill all life

Question 18

Spallanzani

Answer 18

• concluded that Needham did not boil beef gravy long enough
• did the same experiment but increased boiling time and sealed jar tightly
• no life was evident in either jar; spontaneous generation was debunked
• critics argued that too tightly sealed of a jar did not allow air flow for life
  critics argued that prolonged heating destroyed “life force”

Question 19

What was the main difference between Needham’s and Spallanzani’s experiments?

Answer 19

Spallanzani boiled the beef gravy for a longer time, and tightly sealed the covered jar

Question 20

What were the critics of Spallanzani’s experiment?

Answer 20

• prolonged heating destroyed life force
• too tight of a seal did not allow enough air flow

Question 21

Louis Pasteur

Answer 21

-debunked spontaneous generation
- used swan-neck flasks to allow air flow into beef gravy
- boiled beef gravy long enough to kill all bacteria
- no dust in gravy showed no life but dust in gravy appeared cloudy
- concluded that microbes arise from microbes in the air/dust

Question 22

Why were the swan-necked flasks critical in Pasteur’s experiment?

Answer 22

it allowed for airflow into the beef gravy but prevented dust from settling into it

Question 23

Scientific method

Answer 23

observation, hypothesis, experiments, observed results, accept or reject hypothesis

Question 24

What causes disease?

Answer 24

-prior to 1800s attributed to evil spirits, astrology, imbalances, foul vapors
- Pasteur’s discovery that microbes led to spoiling wine led to hypothesis that they are also responsible for disease
- many people still did not believe germs caused disease

Question 25

Koch’s Postulate

Answer 25

-dominated etiology (disease causation)
1. suspected causative agent must be found in EVERY case of the disease and be absent from healthy hosts; agent must also be able to be isolated and grown out of host
2. when agent is introduced to healthy host, the host must get the disease
3. same agent must be found in the diseased experimental host

Question 26

Gram Staining

Answer 26

-purple = gram positive
- pink = gram negative

Question 27

How can we prevent infection and disease?

Answer 27

• semmelwells and handwashing
• Lister’s antiseptic technique
• Nightingdale and nursing; stressed cleanliness/hygiene into nursing practice
• snow and infection control/epidemiology
• jenners vaccine/immunology

Question 28

Earth/history timeline events

Answer 28

-3.5B yrs: first microbe discovered
- 1.3B yrs: first nucleated cell (believed that 2 microbes engulfed each other)
- because microbes were discovered, most lifeforms are dependent of them to survive
-ex. intestines and decomposition of death

Question 29

Relevant events timeline

Answer 29

• 350BC: Aristotle and spontaneous generation
• 180: small pox, fall of roman empire
• 1350: bubonic plague (inflammation of lymph nodes); human catapults to infect enemies
• 1600s: small pox w first suspected biological warfare
• 1670s: Leeuwenhoek and Redi
• 1750: Needham and Spallanzani
• 1820: cholera
• 1850-1880: nightingdale, lister, Pasteur, Kochs postulate
• 1918: Spanish flu