MCL Lectures 1-2

What is the simple definition of a microbe?

A living organism that requires a microscope to be seen and contains a genome to reproduce. Can be uni or multicellular.

Name 3 exceptions to the simple definition of a microbe.

Supersize microbes, microbial communities, viruses

What is a metagenome?

The collection of sequences taken directly from the environment

How did Florence Nightingale contribute to the study of microbiology?

Founded medical statistics and invented polar area chart, which showed what causes soldiers were dying from

How did Robert Hooke contribute to the study of microbiology?

Built the first compound microscope and observes small eukaryotes

How did van Leeuwenhoek contribute to the study of microbiology?

Was the first to observe single celled organisms and discovers bacteria

What is spontaneous generation? Name 3 people that disproved this theory.

The theory that living creatures could arise without parents. Redi, Spallanzani, Pasteur

Name 3 discoveries that disproved the theory of spontaneous generation.

• maggots in decaying meat were the offspring of flies

• a sealed flask of meat broth sterilized by boiling failed to grow microbes

• Pasteur’s swan neck flask experiment

Describe Louis Pasteur’s swan neck flask experiment.

Put a sterilized growth medium in a flask with a S shaped opening that stopped dust and microbes from entering. Nothing grew in the medium.

What is the germ theory of disease?

Many diseases are caused by microbes

How did Robert Koch contribute to the study of microbiology?

Developed Koch’s postulates, a set of criteria to determine if a microbe causes a disease.

Demonstrated chain of infection in anthrax.

How did Angelina and Robert Hesse contribute to the study of microbiology?

Developed solid medium for growing microbes using agar

How did Julius Petri contribute to the study of microbiology?

developed the Petri dish, a double dish container to grow microbes in

Name the Koch Postulates in order.

1. Microbe is always present in diseased host, but absent in healthy

2. Microbe is grown in pure culture with no other microbes present

3. Introduce pure microbe into healthy host—> Individual becomes sick

4. Same microbe re-isolated from now-sick individual

How did Lady Mary Montagu contribute to the study of microbiology?

Introduced the practice of smallpox inoculation to Europe

How did Edward Jenner contribute to the study of microbiology?

Developed the first “vaccine“ for smallpox using cowpox lesion pus

Louis Pasteur developed the first vaccines for which diseases? What were they made of?

Fowl cholera+ rabies. Weakened/attenuated strains of the disease.

How did Ignaz Semmelweis contribute to the study of microbiology?

Ordered doctors to wash their hands with chlorine, an antiseptic agent

How did Alexander Fleming contribute to the study of microbiology?

Discovered that Penicillium mold generated a substance that kills bacteria

What was the first commercial antibiotic?

Penicillin

How was tobacco mosaic disease determined to be a virus and not a bacteria.

It could pass through filters that retained bacteria

What is the Winogradsky column?

A column containing different environments to support different microbes. Has ports on the side to sample from each layer.

Name three developments Sergei Winogradsky was responsible for?

Lithotrophs, enrichment cultures, Winogradsky column

What are endosymbionts?

microbes livings symbiotically inside a larger organism

Describe the endosymbiosis theory.

Mitochondria and chloroplasts were once bacteria that were eaten by a larger species and ended up living inside.

Why was the endosymbiosis theory highly controversial?

It implied a polyphyletic ancestry of living species, instead of the long-held assumption that species evolve only by divergence from a common ancestor (monophyletic ancestry)

How are archaea similar and different from prokaryotes?

Similar size and shape. Different membranes, archaeal ribosomes are similar to eukaryotic ribosomes

True or false: The 16s rRNA gene sequence is found in all organisms except for archaea.

False: archaea contain it too

Function of Electron microscopy:

Allows us to observe cell components, like organelles or membranes(sample must be dead).

Function of ultracentrifuge:

Separates cell components

Function of fluorescence microscopy:

Uses light and fluorescent dyes to image live cells