Week 7: Introduction To Microbiology

Question 1

What is the theory of spontaneous generation?

Answer 1

The theory states that living organisms could arise from non-living matter.

This theory was disproved by Louis Pasteur.

Question 2

Who disproved the theory of spontaneous generation?

Answer 2

Louis Pasteur.

Pasteur’s experiments provided critical evidence against this theory.

Question 3

What experimental method did Pasteur use to demonstrate his findings?

Answer 3

Swan-neck flasks.

These flasks allowed air to enter while preventing contamination from microbes.

Question 4

What conclusion did Pasteur reach regarding air and spontaneous generation?

Answer 4

Air alone is not sufficient to allow for spontaneous generation.

The potential for spontaneous generation might be destroyed by heating.

Question 5

What is the germ theory of disease?

Answer 5

The theory states that diseases are caused by microorganisms.

This marked a significant advancement in understanding disease causation.

Question 6

Who developed postulates to prove the germ theory of disease?

Answer 6

Robert Koch.

Koch’s postulates provide a framework for linking specific microorganisms to specific diseases.

Question 7

Fill in the blank: The theory of _______ states that living organisms could arise from non-living matter.

Answer 7

spontaneous generation.

Question 8

True or False: Louis Pasteur’s experiments supported the theory of spontaneous generation.

Answer 8

False.

Pasteur’s experiments disproved the theory.

Question 9

List the contributions of Robert Koch to microbiology.

Answer 9

• Developed the germ theory of disease
• Created postulates to prove specific microorganisms cause specific diseases.

Question 10

What are Koch’s postulates?

Answer 10

1. The suspected pathogenic organism should be present in all cases of the disease and absent from healthy animals.
2. The suspected pathogenic organism should be grown to pure culture.
3. The pure culture should cause the disease when inoculated into a healthy animal.
4. The organism should be isolated from the inoculated, diseased animal and identified as being identical to the original organism.

Koch’s postulates are a set of criteria established to link specific pathogens to specific diseases.

Question 11

Fill in the blank: The suspected pathogenic organism should be present in all cases of the disease and _______ from healthy animals.

Answer 11

absent

This criterion ensures that the organism is specifically associated with the disease.

Question 12

What is the second postulate of Koch’s postulates?

Answer 12

The suspected pathogenic organism should be grown to pure culture.

This step is essential for ensuring that the organism being studied is not mixed with other microorganisms.

Question 13

What should happen when the pure culture is inoculated into a healthy animal according to Koch’s postulates?

Answer 13

It should cause the disease.

This demonstrates that the organism is capable of causing the disease when introduced to a susceptible host.

Question 14

What is the final step of Koch’s postulates?

Answer 14

The organism should be isolated from the inoculated, diseased animal and identified as being identical to the original organism.

This confirms that the same organism is responsible for the disease in both the original and the inoculated hosts.

Question 15

Who is considered the father of microbiology?

Answer 15

Antonie van Leeuwenhoek

He is known for his pioneering work in observing microorganisms.

Question 16

What instrument did Antonie van Leeuwenhoek use to make observations of microorganisms?

Answer 16

A simple microscope

His use of simple microscopes allowed for detailed observations.

Question 17

What has Antonie van Leeuwenhoek’s observations contributed to?

Answer 17

Our understanding of bacterial morphology

His detailed observations helped establish foundational knowledge in microbiology.

Question 18

What is a key difference between eukaryotic and prokaryotic cells?

Answer 18

Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells lack a nucleus

This distinction is fundamental in cell biology.

Question 19

What is the evolutionary history of bacteria?

Answer 19

Bacteria have a long evolutionary history and are among the oldest life forms on earth

This highlights the significance of bacteria in the history of life.

Question 20

What is the purpose of the Ziehl-Neelsen Stain?

Answer 20

Differentiates acid-fast bacteria from other bacteria

Acid-fast bacteria include organisms like Mycobacterium tuberculosis.

Question 21

What are the steps involved in the Ziehl-Neelsen Stain?

Answer 21

1. Stain with carbol fuchsin
2. Rinse
3. Treat with acid
4. Counterstain with methylene blue

Question 22

What is the result of the Ziehl-Neelsen Stain for acid-fast bacteria?

Answer 22

Retain red stain due to waxy lipids in cell wall; others stain blue

Question 23

What is the purpose of Gram Staining?

Answer 23

Differentiates bacteria based on cell wall structure

Question 24

What are the two types of bacteria identified by Gram Staining?

Answer 24

• Gram-positive (stain purple)
• Gram-negative (stain pink)

Question 25

What is the importance of Gram Staining?

Answer 25

Provides clues to bacterial identity and treatment options

Question 26

What are Koch's Postulates?

Answer 26

Established foundation for applied medical microbiology and immunology

Question 27

What is the purpose of Koch's Postulates?

Answer 27

To identify the specific causative agent for a disease

Question 28

Who proved that bacteria can cause disease?

Answer 28

Robert Koch ## Footnote Koch is a key figure in microbiology and is known for his postulates.

Question 29

What purification procedures did Koch develop?

Answer 29

Purification procedures for microorganisms on solid media ## Footnote This was essential for isolating pure cultures of bacteria.

Question 30

Which bacterium causes tuberculosis?

Answer 30

Mycobacterium tuberculosis ## Footnote Koch's research was pivotal in linking this bacterium to tuberculosis.

Question 31

What staining procedure did Koch develop for Mycobacterium tuberculosis?

Answer 31

A staining procedure specifically for Mycobacterium tuberculosis ## Footnote This was crucial for identifying the bacterium in clinical samples.

Question 32

What characterizes Gram-positive bacteria?

Answer 32

Thick layer of peptidoglycan, stain purple ## Footnote Gram-positive bacteria retain the crystal violet stain used in Gram staining.

Question 33

What characterizes Gram-negative bacteria?

Answer 33

Thinner layer of peptidoglycan, stain pink ## Footnote Gram-negative bacteria do not retain the crystal violet and are counterstained pink.

Question 34

What is the Gram staining technique?

Answer 34

Uses crystal violet, iodine solution, ethanol, and safranin ## Footnote This technique differentiates between Gram-positive and Gram-negative bacteria.

Question 35

What type of cell wall does Mycobacterium tuberculosis have?

Answer 35

Thick, waxy, and hydrophobic ## Footnote This unique structure contributes to its resistance to certain antibiotics.

Question 36

How does Mycobacterium tuberculosis appear in Gram staining?

Answer 36

Stains purple, appears Gram-positive ## Footnote Despite its unusual cell wall, it retains the purple color in the Gram stain.

Question 37

What are methods used for bacterial identification?

Answer 37

Selective growth media, specialized tests (Enterotube), immuno-tests, PCR and sequencing ## Footnote These methods help in accurately identifying and differentiating bacteria in clinical samples.

Question 38

What is the goal of bacterial identification?

Answer 38

To accurately identify and differentiate bacteria in clinical samples ## Footnote This is crucial for effective diagnosis and treatment.

Question 39

How many bacteria do humans harbor compared to their own cells?

Answer 39

Humans harbor 10x more bacteria than cells ## Footnote This highlights the extensive microbial presence in the human body.

Question 40

How does the genetic diversity of bacteria compare to humans?

Answer 40

Bacteria have 100x more genes than human genes ## Footnote This indicates a vast genetic diversity and adaptability among bacteria.

Question 41

What percentage of bacteria in our bodies are considered harmless or beneficial?

Answer 41

95% harmless/beneficial ## Footnote This suggests that the majority of bacteria contribute positively to human health.

Question 42

What historical context is provided regarding fungi?

Answer 42

Fungi were known, and mycologists studied spoilage of crops. Unicellular pathogenic fungi were discovered later. ## Footnote This highlights the early understanding of fungi in agriculture and their later recognition as pathogens.

Question 43

What was the sequence of discovery for bacteria and viruses?

Answer 43

Bacteria were identified in plants, then animals, and finally humans. Viruses were discovered later. ## Footnote This sequence illustrates the progressive understanding of microbial life.

Question 44

What do Koch's Postulates validate?

Answer 44

They remain valid for proving that a specific fungus or virus causes a disease. ## Footnote Koch's Postulates are a set of criteria for establishing a causative relationship between a microbe and a disease.

Question 45

What is Saccharomyces cerevisiae commonly known as?

Answer 45

Baker's yeast. ## Footnote This organism is widely used in research due to its significance in fermentation and cellular studies.

Question 46

Why is Saccharomyces cerevisiae considered a model organism?

Answer 46

Due to its easy manipulation and understanding of cellular metabolism. ## Footnote Model organisms are crucial for biological research as they allow scientists to understand complex life processes.

Question 47

What advantages does Saccharomyces cerevisiae provide for research?

Answer 47

Provides accessible research tools for investigating life processes, with similar features across all cells (e.g., bacteria, yeast). ## Footnote These similarities make it easier to extrapolate findings to other organisms.

Question 48

What impact has Saccharomyces cerevisiae had on scientific fields?

Answer 48

Has led to enormous advances in genetics, biochemistry, and understanding of cellular metabolism. ## Footnote The use of this yeast in research has significantly contributed to multiple scientific breakthroughs.

Question 49

What is the first step in identifying the cause of an infection?

Answer 49

Simple observation isn't enough

Question 50

Which areas of the body are typically sterile?

Answer 50

Spinal fluid, blood, joint fluid, pleural fluid, middle ear, and urine

Question 51

What is a challenge when collecting samples from sterile sites?

Answer 51

Samples can be easily contaminated upon exiting the body

Question 52

What technique is used to separate bacteria on agar plates?

Answer 52

Streaking technique

Question 53

At what temperature should bacteria be incubated to grow overnight?

Answer 53

37°C

Question 54

What is the first of Koch's Postulates?

Answer 54

Isolate the organism

Question 55

What is the second of Koch's Postulates?

Answer 55

Grow a pure culture

Question 56

What is the third of Koch's Postulates?

Answer 56

Inject into a healthy animal

Question 57

What is the fourth of Koch's Postulates?

Answer 57

Re-isolate the same bacteria from the sick animal