Microbiology and Spontaneous Generation Quiz
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Questions and Answers

Which historical figure is noted for discovering single-celled microorganisms?

  • Joseph Lister
  • Antonie van Leeuwenhoek (correct)
  • Robert Koch
  • Louis Pasteur

The theory of spontaneous generation was widely accepted even after microorganisms were discovered.

True (A)

What ancient idea explains the belief that living things come from non-living matter?

spontaneous generation

The spontaneous production of living entities from soiled clothes and wheat grains refers to a __________ recipe.

<p>17th-century</p> Signup and view all the answers

What was used to explain food spoilage according to historical beliefs?

<p>Vital forces (A)</p> Signup and view all the answers

The 17th-century belief in spontaneous generation is still widely accepted in modern science.

<p>False (B)</p> Signup and view all the answers

In what duration did the spontaneous production of maggots occur according to the historical belief?

<p>Days</p> Signup and view all the answers

Which of the following bacterial species is known for forming endospores?

<p>Bacillus anthracis (A)</p> Signup and view all the answers

Endospores are sensitive to extreme environmental conditions.

<p>False (B)</p> Signup and view all the answers

What are endospores primarily formed in response to?

<p>Harsh environmental conditions such as lack of nutrients.</p> Signup and view all the answers

Endospores are extremely resilient to __________ temperatures.

<p>boiling</p> Signup and view all the answers

Match the following terms with their descriptions:

<p>Endospores = Resilient structures formed by bacteria under stress Vegetative cells = Active and metabolically active bacterial forms Bacillus anthracis = A bacterium that can form endospores Clostridium tetani = Another bacterium known for endospore formation</p> Signup and view all the answers

What is the heat-resistant form of bacteria discovered by Ferdinand Cohn?

<p>Endospore (A)</p> Signup and view all the answers

Microorganisms can be classified only into unicellular organisms.

<p>False (B)</p> Signup and view all the answers

Name one eukaryotic microorganism mentioned in the content.

<p>Saccharomyces cerevisiae</p> Signup and view all the answers

Escherichia coli is classified as a __________.

<p>prokaryote</p> Signup and view all the answers

What temperature was maintained for the hay infusion on Day 2?

<p>37°C (C)</p> Signup and view all the answers

Bacteria can be observed with the naked eye.

<p>False (B)</p> Signup and view all the answers

What could primarily cause food spoilage?

<p>Microorganisms</p> Signup and view all the answers

What was the main conclusion of John Tyndall's 1877 experiment concerning hay infusion?

<p>Microorganisms exist in two forms, one sensitive to heat and one resistant to boiling. (C)</p> Signup and view all the answers

The presence of microbial growth in hay infusion is indicated by the infusion remaining clear.

<p>False (B)</p> Signup and view all the answers

What experimental technique did Tyndall develop to eliminate heat-resistant microbes?

<p>Tyndallisation</p> Signup and view all the answers

Microorganisms that are sensitive to heat will be killed by boiling, while those that are _______ can survive.

<p>heat-resistant</p> Signup and view all the answers

Match the following observations of hay infusion with their implications:

<p>Clear infusion = Absence of microbial growth Cloudy infusion = Presence of microbial growth Tyndallisation = Elimination of heat-resistant microbes</p> Signup and view all the answers

Which component was essential for microbial growth in Tyndall's hay infusion experiment?

<p>Hay (D)</p> Signup and view all the answers

Pasteur fully supported the concept of spontaneous generation.

<p>False (B)</p> Signup and view all the answers

What type of environment was used to create the hay infusion?

<p>Water collected from a pond, lake, stream, or puddle</p> Signup and view all the answers

What is the primary method of reproduction for bacteria?

<p>Binary fission (A)</p> Signup and view all the answers

Boiling a hay infusion will always eliminate all bacterial growth.

<p>False (B)</p> Signup and view all the answers

What is the result of boiling a hay infusion that contains endospores?

<p>The hay infusion turns cloudy.</p> Signup and view all the answers

Bacteria are commonly found in hay infusions due to their natural habitat in the _____ .

<p>soil</p> Signup and view all the answers

Match the following observations to their respective hay infusions:

<p>Hay infusion without endospores = Remains clear Hay infusion with endospores = Turns cloudy</p> Signup and view all the answers

What role does sugar in hay play for bacteria?

<p>Acts as a nutrient source (C)</p> Signup and view all the answers

John Tyndall's experiment demonstrated that boiled hay infusion remains clear when endospores are present.

<p>False (B)</p> Signup and view all the answers

In Tyndall's experiment, what was the duration of boiling the hay infusion?

<p>1 hour</p> Signup and view all the answers

In Tyndall's experiment, the hay infusion that contains _____ will show the presence of microbial growth after boiling.

<p>endospores</p> Signup and view all the answers

Why do hay infusions provide an excellent medium for bacterial growth?

<p>They contain nutrients (D)</p> Signup and view all the answers

What is the primary role of the exosporium in endospores?

<p>Protection and adhesion (B)</p> Signup and view all the answers

Boiling for 5 hours is sufficient to kill endospores.

<p>False (B)</p> Signup and view all the answers

What substance is deposited in the endospore that helps remove water and increase resistance to heat?

<p>calcium dipicolinate</p> Signup and view all the answers

The process of _____ eliminates vegetative cells and allows endospores to be killed upon subsequent heat treatment.

<p>Tyndallisation</p> Signup and view all the answers

Match the following components of endospores with their functions:

<p>Cortex = Protection against radiation Spore coat = Chemical resistance Exosporium = Adhesion and virulence Special proteins = DNA protection from chemicals</p> Signup and view all the answers

How long should the heat treatment be repeated during Tyndallisation?

<p>Three times (B)</p> Signup and view all the answers

The incubation period between heat treatments helps endospores to germinate into vegetative cells.

<p>True (A)</p> Signup and view all the answers

What temperature is used for incubation during Tyndallisation?

<p>37°C</p> Signup and view all the answers

Flashcards

Spontaneous Generation

The idea that living things can arise from non-living matter.

Abiogenesis

The process of living things arising from non-living matter. This was the traditional explanation for phenomena like food spoilage.

Redi's Experiment

The 17th-century experiment by Francesco Redi to disprove spontaneous generation. It showed that flies were the source of maggots, not decaying meat.

Spontaneous Mouse Recipe

A 17th-century recipe for spontaneous production of mice. The recipe involved sweaty clothes, wheat grains, and 21 days. This was used to support spontaneous generation.

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Biogenesis

The theory that living things can only originate from other living things.

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Late 1600s

The period in the 17th century marked by the discovery of microorganisms by Antonie van Leeuwenhoek.

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Antonie van Leeuwenhoek

The Dutch scientist who discovered microorganisms in the late 1600s, using his self-made microscope, paving the way for challenging the prevailing view of spontaneous generation.

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Decomposition

The process of living things breaking down and decaying.

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What are microorganisms?

Microorganisms, often called microbes, are organisms that are too small to be seen with the naked eye. Most are unicellular, like bacteria and yeasts, but some are multicellular, like molds.

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What are bacteria?

Bacteria are single-celled prokaryotes, meaning they lack a nucleus. An example is Escherichia coli, commonly found in the gut.

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What are yeasts?

Yeasts are single-celled eukaryotes, meaning they have a nucleus. Saccharomyces cerevisiae, used in baking, is a common example.

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What are molds?

Molds are multicellular eukaryotes, meaning they're made up of many cells. Rhizopus stolonifer, commonly found on bread, is a familiar example.

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What are endospores?

Endospores are highly resistant structures formed by some bacteria. They can survive harsh conditions and are difficult to kill.

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What is an endospore?

A dormant, highly resistant form of a bacteria that forms under harsh conditions.

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Why are endospores resistant?

Endospores are able to withstand very harsh conditions, such as extreme temperatures, radiation, disinfectants, and dehydration.

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When do endospores form?

Endospores form in response to adverse environmental conditions, such as lack of nutrients, to ensure the bacterium's survival.

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What is a vegetative cell?

A vegetative cell is a regular, actively growing bacterial cell.

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What happens to an endospore when conditions improve?

When conditions improve, the endospore can germinate and return to its vegetative state.

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Hay Infusion

A liquid containing organic materials that support the growth of microorganisms, like bacteria and fungi.

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John Tyndall's Experiment (1877)

A scientific experiment designed to test the theory of spontaneous generation. It involves exposing a sterile hay infusion to the air, observing for microbial growth.

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Tyndallisation

A form of heat treatment used to eliminate heat-resistant microbes, especially bacterial endospores.

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Bacterial Endospores

A resistant, dormant form of bacteria that can survive harsh environments, like boiling.

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Boiling Hay Infusion

The process of boiling a hay infusion for a prolonged period, aiming to kill all existing microorganisms.

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Clear Hay Infusion

The state of the hay infusion where no microbial growth is observed, indicating the absence of microorganisms.

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Cloudy Hay Infusion

The state of the hay infusion where microbial growth is evident, indicated by clouding or turbidity.

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Bacteria

Single-celled organisms that reproduce asexually by dividing in two.

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Binary Fission

A method of bacterial reproduction where one cell divides into two identical cells.

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Endospores

Spores are resistant structures produced by some bacteria to survive harsh conditions.

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Food Spoilage

The decay of food due to the growth of microorganisms, like bacteria.

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Infusion

A liquid containing nutrients, often used to grow microorganisms in a laboratory.

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Medium

A substance containing nutrients that support bacterial growth.

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Boiling

The process of killing microorganisms, including bacteria, by heating them.

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Sterility

The state of being free from microorganisms.

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Experiment

A scientific experiment designed to test a hypothesis.

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Observation

The act of carefully observing and noting changes or events.

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When do bacteria form endospores?

Endospores are formed when bacteria experience unfavorable conditions like lack of nutrients or extreme temperatures. They are essentially a dormant survival state.

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What is the role of the exosporium?

The outermost layer of some endospores, acting as a shield, ensuring adhesion, and contributing to the spore's ability to cause disease.

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What role do the cortex and spore coat play in endospore survival?

They provide a thick barrier against radiation and chemicals, protecting the internal structures of the spore.

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How does calcium dipicolinate aid in endospore resilience?

Calcium dipicolinate is a compound stored within endospores, contributing to dehydration and resistance to high temperatures.

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How are endospores' DNA protected from chemicals?

Special proteins within the endospore core directly safeguards the DNA from damaging chemicals.

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What is Tyndallisation?

Tyndallisation is a method for sterilisation using repeated cycles of heating and incubation. It aims to kill both vegetative cells and endospores by allowing endospores to germinate into vulnerable cells between heating cycles.

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Why is Tyndallisation more effective than simple boiling for sterilizing endospores?

Boiling for 5 hours is insufficient to eliminate all endospores due to their exceptional heat resistance. Tyndallisation, with its repeated heating and incubation cycles, is more effective in achieving complete sterilization.

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Study Notes

Microbiology Lesson 1: Spontaneity

  • The module chair is Won Choong Yun
  • The last update date is September 23, 2024
  • The course is A221 Microbiology
  • The lesson is Lesson 1

Interactive Seminar Schedule

  • 8:30am - 9:45am: Module story and ice breaker
  • 9:45am - 10:30am: Break
  • 10:30am - 12:00pm: Lecture Part I and Worksheet Activity Part I
  • 12:00pm - 1:30pm: Lunch break
  • 1:30pm - 3:00pm: Lecture Part II and Worksheet Activity Part II
  • 3:00pm - 3:30pm: PQ and discussion
  • 3:30pm: Class ends

Lecture Part I

  •  Discussion of spontaneous generation (abiogenesis): The historical belief that life arose from non-living matter.
  •  17th-century recipes for spontaneously producing mice and maggots.

17th Century Recipe for Mice

  • Materials: Sweaty, soiled clothes; wheat grains
  • Process: Place the materials together.
  • Result: Mice appeared after 21 days.

17th Century Recipe for Maggots

  • Materials: Meat
  • Process: Leave the meat exposed to the air.
  • Result: Maggots appeared after several days.

Spontaneous Generation vs. Biogenesis

  • Abiogenesis: Living things arise from non-living things.
  • Biogenesis: Living things arise from living things.

Francesco Redi's 1668 Experiment

  • Experimental Setup: Jars with meat, sealed, covered with gauze
  • Observations: Open jar had maggots, sealed jar had no maggots, gauze-covered jar had maggots only on the gauze
  • Conclusion: Maggots did not spontaneously generate; they developed from fly eggs.

John Needham's 1745 Experiment

  • Experimental Setup: Broth boiled briefly and sealed
  • Observations: Broth became cloudy (microbial growth)
  • Conclusion: Microbes formed spontaneously

Louis Pasteur's 1859 Experiment

  • Experimental Setup: Broth in open flasks, cotton-plugged flasks, S-shaped flasks
  • Observations: Open flask grew microbes; cotton-plugged flask did not grow microbes; S-shaped flask did not grow microbes.
  • Conclusion: Microbes did not spontaneously generate in the sealed flasks; airborne microbes were the source of contamination

John Tyndall's 1877 Experiment

  • Experimental Setup: Hay infusion (boiled for 1 hour and allowed to cool).
  • Observations: Hay infusion that did not contain endospores did not produce microorganisms and the infusion that did have endospores produce organisms
  • Conclusion: Some microorganisms survive boiling and need more than one round of boiling to kill them completely. 

Discovery of Bacterial Endospores

  • Ferdinand Cohn found endospores - heat-resistant forms of bacteria.
  • Tyndallisation is a technique to eliminate heat-resistant microbes via repeated rounds of heating to kill vegetative forms and allow the endospores to germinate into vegetative forms , thus increasing the killing rate.

Microbiology of Food Spoilage

  • Microorganisms—especially bacteria, yeasts, and molds—are the primary cause of food spoilage.
  • Different shapes: Cocci, bacilli, vibrio, spirilla

How Bacteria are Classified

  • The three-domain system (Bacteria, Archaea, Eukarya) classifies living organisms based on rRNA nucleotide sequences.

How Microorganisms are Named

  • Binomial nomenclature is used (Genus species).
  • Scientific names are italicized when typed and underlined when written

Bacterial Cell Structure and Function

  • Prokaryotic, meaning they lack a nucleus
  • Various sizes (typically 1-10 µm)

Bacterial Reproduction

  • Binary fission

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A221 Microbiology Lecture Notes - AY 2024 Sem 2 - PDF

Description

Test your knowledge on the history and concepts of microbiology, including the discovery of microorganisms and the theory of spontaneous generation. This quiz covers key historical beliefs about living organisms and their environments, particularly focusing on endospores and food spoilage. Dive into the fascinating world of microorganisms and their historical significance.

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